Community transmission is widespread, given that many new cases are not among known contacts under follow up. Almost half of daily new confirmed cases are detected as deaths, reflecting late case detection due to the outbreak’s vast geographical spread, compounded by insufficient human resources to conduct surveillance activities, lack of community trust, insufficient bed capacities and insecurity due to the ongoing complex humanitarian crisis. Safe and dignified burial also remains challenging: some community members continue to express concerns about the procedure, and human resource capacity is currently insufficient to meet the demand for prompt safe and dignified burials.

Alert System Performance and Trends: Democratic Republic of the Congo

Following the identification of the outbreak in May 2026, the Ministry of Health of the Democratic Republic of the Congo adapted the recommended Ebola virus disease case definitions to guide the detection of new BVD cases. As a crucial part of surveillance, alert management systems were put in place at health zone level, including toll-free numbers for reporting of alerts from both the community and health facilities. All alerts received are documented and investigated by an investigation team; if the alert is determined to meet the outbreak case definition for suspected cases, the alert is then validated. The validated alerts are classified as suspected cases or deaths, and, if alive, isolated in a designated isolation facility while awaiting laboratory testing; or, if deceased, buried in a safe and dignified burial way after a swab is collected for testing.

Between the official outbreak declaration on 15 May 2026, and the end of epidemiological week 30 (26 July 2026), over 55 000 total alerts were recorded across the five affected provinces. Mirroring the increase in confirmed cases, alert volumes have increased steadily since the beginning of the outbreak, peaking with a daily total of 1937 alerts recorded across four provinces (977 alerts in North Kivu, 866 alerts in Ituri, 49 alerts in Tshopo, and 45 alerts in Haut-Uele) on 24 July 2026 (Figure 2).

Figure 2. Trends in Daily Total Alerts in DRC by Province

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Trends in Daily Total Alerts in DRC by Province.

The two provinces with the highest case burden (Ituri and North Kivu) accounted for the majority of alerts, though with different epidemiological profiles: Ituri reported 2901 confirmed cases from over 20 000 alerts (approximately one confirmed case per seven alerts), compared to only 314 confirmed cases from approximately 33 000 alerts in North Kivu (approximately one confirmed case per 105 alerts). In general, a large number of alerts for each subsequently confirmed case demonstrates the high sensitivity expected of a well-functioning alert system. The relatively lower number of alerts per confirmed case in Ituri signals that the outbreak continues to outpace the capacity to adequately respond to it. Another key indicator of surveillance system responsiveness is the percentage of alerts investigated within 24 hours. This figure has averaged approximately 83.5% nationally over the reporting period, with variation by province and over time. North Kivu has maintained comparatively high and stable investigation rates throughout the outbreak, averaging almost 95% of alerts investigated within 24 hours. Similarly, Sud-Kivu has a high average investigation rate of almost 83%, though it has recorded a notably smaller volume of both alerts and confirmed cases (602 alerts and three confirmed cases) than other provinces. Ituri, the province with the highest burden of confirmed cases, has maintained a lower average investigation rate of about 66%. A noticeable drop was observed during epi week 27 (29 June to 5 July), coinciding with a surge in alert volume, suggesting strain on investigation capacity during periods of peak transmission (Figure 3). Ongoing strikes across the wider region, affecting Ituri province throughout the month of July, have likely also contributed to the lower investigation rate.

Figure 3. Weekly Alerts and Investigation Rate (North Kivu and Ituri).

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Weekly Alerts and Investigation Rate (North Kivu and Ituri).

Another useful indicator for assessing alert system functionality is the proportion of validated alerts in which the individual was still alive versus already deceased at the time of alert validation. Over the past three complete epidemiological weeks (weeks 28-30), approximately 69% of alerts validated were alive and 31% were deceased at the time of validation. When broken down by province, there is substantial variance: in Sud Kivu, 100% of alerts were alive at the time of validation, albeit based on a small sample of only 43 alerts. Tshopo also had a high rate of alerts alive at time of validation, at 88.5%. In contrast, Haut Uele had the low percentage of alerts alive of all provinces during this period, at 55.8%. Amongst the two highest-burden provinces, Ituri had 72.1% of validated alerts alive and 27.9% deceased at the time of validation. In North Kivu, in contrast, only 59.5% were alive and 40.5% were deceased. (Figure 4) This is not a recent trend; rather, North Kivu has observed a low percentage of alerts alive at point of validation throughout the outbreak (overall average of 61.3% alive and 38.7% deceased at time of validation). This finding is notable because North Kivu has simultaneously reported the highest total number of alerts, the highest average 24-hour investigation rate, yet one of the lowest percentage of alerts alive at time of alert validation of any province. The reasons for the high proportion of deceased alerts in North Kivu are currently under investigation.

Figure 4. Recent Trends in Daily Validated Alerts by Province.

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Recent Trends in Daily Validated Alerts by Province.

Of the over 55 000 alerts received since the beginning of the outbreak, approximately 23.5% (around 12,900) were validated as suspected cases. Of these suspected cases, 3262 were subsequently confirmed through laboratory testing; confirmed cases represent about 6% of all alerts and 25% of suspected cases.

Figure 5. Alerts, Suspected Cases, Confirmed Cases in DRC.

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Alerts, Suspected Cases, Confirmed Cases in DRC.

As aforementioned,the percentage of alerts that are ultimately validated and therefore considered suspected cases varies between provinces, ranging from approximately 45% in Tshopo and 43% in Ituri to almost 11% in North Kivu. The pipeline from total alerts to suspected cases to confirmed cases is illustrated at the national level in Figure 5 and at the provincial level in Figure 6.

Figure 6. Alerts, Suspected Cases, Confirmed Cases in DRC by Province Level.

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Alerts, Suspected Cases, Confirmed Cases in DRC by Province Level.

Improving the Alert System

To end the BVD outbreak in the Democratic Republic of the Congo, it will eventually be necessary to identify every single infectious case before they have the opportunity to transmit the infection further. The foundation of this timely identification is a robust alert management system: timely and comprehensive alert notification and investigation must be present in all affected areas, as well as areas receiving travelers from affected areas, and covering both the community and health facilities. Important enablers of robust alert management include sufficient and well-trained human resources, logistical and financial support for the alert system, community trust, timely laboratory support, and sufficient clinical management and safe and dignified burials capacity to properly manage persons identified through the alert system.

The vaccine position papers are developed by the WHO SAGE Secretariat with input from WHO staff at the headquarters and regional levels. The vaccine position papers summarize essential background information on diseases and vaccines and conclude with the current WHO position on the use of vaccines worldwide. The position papers are reviewed by a large group of external subject-matter experts and end-users before finalization. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) and the evidence-to-decision tables are published alongside the position papers. The methods followed by SAGE³ and the processes⁴ for preparation of vaccine position papers are described on the WHO website.

This position paper is concerned with vaccines and vaccination against COVID-19 and supersedes previous interim guidance issued by WHO on this subject. Since the WHO declaration of the COVID-19 Public Health Emergency of International Concern (PHEIC) in early 2020,⁵ WHO has issued a comprehensive set of strategic and guidance documents to support countries in planning, implementing, monitoring, optimizing and assessing the impact of COVID-19 vaccination. These included the WHO SAGE values framework for the allocation and prioritization of COVID-19 vaccination;⁶ successive roadmaps to prioritize vaccine use in response to evolving evidence, vaccine supply and epidemiological context;⁷ vaccine product-specific and platform interim recommendations for the WHO Emergency Use Listing (EUL) and WHO prequalified COVID-19 vaccines;⁸ COVID-19 vaccine delivery guidance, resources and tools;⁹ and an overarching global COVID-19 vaccination strategy.¹⁰,¹¹

In May 2023, WHO announced that COVID-19 no longer constituted a PHEIC due to decreasing trends in COVID-19 deaths and COVID-19-related hospitalizations and intensive care unit (ICU) admissions, and the high levels of population immunity to SARS-CoV-2.¹² In December 2025, WHO published the Strategic plan for coronavirus disease threat management for the period 2025-2030,¹³ which builds on and supersedes previous WHO strategic preparedness and response plans and provides the global framework for the sustained and integrated management of COVID-19 and other coronavirus diseases. Recommendations in this position paper are provided in the context of Omicron and its sub-lineages being the predominant circulating SARS-CoV-2 variant of concern with high population-level immunity to SARS-CoV-2 and the availability of mRNA and protein subunit COVID-19 vaccines. The recommendations in this position paper will remain valid for new variant-adapted COVID-19 vaccines. They will be revised should new SARS-CoV-2 variants of concern arise, if there are significant changes in COVID-19 epidemiology, or if new evidence indicates that vaccine performance warrants modification of the policy recommendations.

Background

Epidemiology

SARS‑CoV‑2 is a highly transmissible coronavirus first reported to WHO in December 2019. Through mutation and recombination, the virus has evolved from the original (ancestral) strain into a variant of concern including Alpha, Beta, Gamma, Delta and Omicron, which differ in transmissibility, immune escape and/or disease severity. The virus spreads mainly through infectious respiratory particles transmitted at close range and in poorly ventilated indoor environments, with transmission occurring from both asymptomatic and symptomatic individuals.¹⁴

Between 2020 and the end of 2025, over 778 million confirmed cases and more than 7 million COVID-19 deaths worldwide have been reported to WHO, although the true death toll is likely to be higher due to under-reporting and differences in how countries record and report COVID-19 fatalities.¹⁵

Seroprevalence estimates suggested that global population immunity against SARS-CoV-2 had reached approximately 90% by April 2022.¹⁶ While this widespread immunity from prior SARS-CoV-2 infection and COVID-19 vaccination has substantially reduced disease severity, hospitalizations and deaths, SARS-CoV-2 continues to evolve, with Omicron sub-lineages predominating globally since 2022.

Global surveillance remains limited by reduced genomic sequencing and reporting, especially in low‑ and middle‑income countries, although wastewater and sentinel systems indicate ongoing widespread circulation alongside seasonal influenza and respiratory syncytial virus (RSV). No clearly established or predictable seasonal transmission pattern has yet emerged for SARS-CoV-2.¹⁷

By mid-May 2026, the number of monthly global confirmed COVID-19 deaths reported to WHO had declined to approximately 380 and ICU admissions had decreased compared with previous years.¹³ However, these figures are likely to be affected by substantial under-reporting. For example, between January and mid-May 2026, the United States of America alone reported 5000 deaths related to COVID-19.¹⁸

Groups at higher risk of severe COVID-19 disease

While anyone can be infected with SARS-CoV-2, certain population groups are at higher risk of severe outcomes. This pattern has persisted across SARS-CoV-2 variants. The risk of severe illness from COVID-19 follows a clear age-related gradient. Older adults remain disproportionately affected by COVID-19, with those aged 65 years and older accounting for almost 90% of all COVID-19 deaths reported to WHO in 2025.¹⁷

During the early phase of the pandemic, COVID-19 caused substantially higher incidence, hospitalization, and mortality than seasonal influenza. By 2024–2025, increasing population immunity has markedly reduced disease severity, and recent limited data suggest that COVID-19 mortality rates among older adults are comparable to – or in some settings higher than – those associated with seasonal influenza. Across COVID-19, RSV and seasonal influenza, the highest mortality rates during the most recent reporting period are consistently observed in, or include, the oldest age groups.¹⁹,²⁰,²¹,²² In addition, adults aged ≥50 years, both post-discharge mortality and the risk of readmission at 90 days after discharge were higher (2022–2025) among patients with COVID-19 compared to those with seasonal influenza or RSV.²³

Chronic conditions have been shown to be present in approximately half of COVID-19 patients²⁴ and are associated with an increased risk of severe outcomes.^37,25 Data from the United States of America shows that since 2023, over 90% of hospitalized patients due to COVID-19 had at least one underlying comorbidity. ²⁶ A retrospective cohort study of approximately 19 000 hospitalized COVID-19 patients aged 15 years and above from six European countries, using severe acute respiratory infection surveillance data collected between January 2024 and December 2025, similarly found that most patients had at least one underlying condition. However, age was the dominant driver of severe outcomes.²⁷

A meta-analysis conducted during the Omicron era indicates that the elevated risk for severe COVID-19 outcomes among individuals with chronic conditions, such as cardiovascular disease, chronic kidney disease, chronic respiratory disease, diabetes mellitus, chronic liver disease, neurological conditions and/or severe obesity, persists. ²⁸ Individuals with multiple comorbidities have a compounded risk for severe COVID-19. ²⁹,³⁰ Cardiovascular disease, chronic kidney disease and cerebrovascular disease showed the strongest associations with mortality (RR >2.0),³¹ while obesity, diabetes and hypertension were consistently linked to increased disease severity (OR ≈ 1.3–2.2).37,38

Adults, adolescents, and children with moderate-to-severe immunocompromising conditions are also at greater risk of severe COVID-19, regardless of age, although risk increases with age.³²

Pregnant women³³ are at increased risk of severe COVID-19 outcomes compared with non-pregnant women of reproductive age. These outcomes include hospitalization, ICU admission, a need for mechanical ventilation, and adverse pregnancy outcomes such as preterm birth. Data gathered by WHO between March 2020 and March 2023 from 165 761 pregnant women identified advanced maternal age and pre-existing comorbidities as risk factors for severe disease, consistent with those risk factors observed in the general population.³⁴ A review of 14 studies conducted when Omicron was circulating (2023–2025) suggests that while Omicron infections during pregnancy carry lower maternal risk than Delta and earlier variants of concern, infection still increases the risk of adverse outcomes compared with pregnancies without SARS-CoV-2 infection.³⁵ Across multiple studies conducted during the Omicron era, SARS-CoV-2 infection during pregnancy was linked to a 64% (95% CI:31–107) increased risk of maternal ICU admission and a 26% (95% CI:14–38) increased risk of preterm birth.²⁷ Among infected pregnant women, vaccination before or during pregnancy was associated with a 36% reduction in the risk of maternal morbidity or mortality compared with no vaccination (95% CI:12–65). Maternal morbidity included pregnancy complications (vaginal bleeding, pregnancy-induced hypertension, pre-eclampsia, eclampsia, and HELLP syndrome), preterm birth, infection requiring antibiotics, ICU admission, referral to higher-level care, or maternal death.³⁶ Vaccination prior to and during pregnancy was associated with lower risk of maternal hospitalization, ICU admission and adverse pregnancy outcomes (preterm birth) in both the Delta and Omicron variant periods.³⁷

Children under 15 years of age represented less than 1% of reported deaths to WHO in 2025, with the majority of paediatric fatalities occurring among those younger than five years.¹⁷ Among children, infants (especially those < 3 months) have the highest COVID-19 hospitalization rates frequently characterized by co-infections. Although the frequency of severe outcomes in children varies between different settings. 19,20,22,³⁸,³⁹

During the first years of the COVID-19 pandemic, infections and deaths in health workers⁴⁰ were high in many countries.⁴¹ Available evidence indicates that infection risk among health workers increasingly reflects levels of community transmission, although elevated exposure risk may persist in some healthcare settings and during periods of intense transmission.⁴² This is especially true in settings with inadequate infection prevention and control measures (such as personal protective equipment). Studies conducted in 2023 and 2024 indicate that SARS-CoV-2 infection was the leading cause of absenteeism of health workers, alongside seasonal influenza and RSV, with implications for the resilience of health systems.⁴³,⁴⁴,⁴⁵

Health workers may also contribute to transmission to populations at increased risk of severe COVID-19, given their frequent close and prolonged contact with these individuals.

Pathogen

SARS-CoV-2 is an enveloped, positive-sense RNA betacoronavirus of which the genome encodes, inter alia, the spike protein which mediates host cell entry and serves as the main target of neutralizing antibodies and current vaccines.⁴⁶ Since early 2022, Omicron and its numerous sub-lineages have predominated globally, sharing features such as high transmissibility driven by immune escape and generally lower intrinsic disease severity. The virus’s ability to infect diverse animal species and cause spillover and spillback events highlights the need for integrated One Health surveillance and risk assessment.⁴⁷

Disease

The incubation period of COVID-19 ranges from 2 to 14 days (typically from 2–4 days for the Omicron variant). Symptoms vary widely from asymptomatic infection to severe disease and include fever, cough, fatigue, shortness of breath, myalgia, sore throat, nasal congestion, anosmia, ageusia, headache and gastrointestinal symptoms. However, the prominence of certain symptoms, such as anosmia/ageusia, has decreased over time.⁴⁸ SARS-CoV-2 can cause endothelial dysfunction, microvascular injury and thromboinflammation, leading to complications in multiple organs. Severe cases may progress to pneumonia, acute respiratory distress syndrome, sepsis, thromboembolic events and multi‑organ failure. Children generally develop milder illness than adults, with fever and cough the most common. Infants may present with nonspecific signs such as feeding difficulties. Multisystem inflammatory syndrome in children⁴⁹ is rare and appears to be decreasing in incidence.⁵⁰

Post-COVID-19 condition (PCC) is characterized by persistence of symptoms ≥3 months after SARS-CoV-2 infection and may even affect individuals with mild initial disease. WHO clinical case definitions are available for PCC in adults⁵¹ and children.⁵² Long COVID-19 (LC) is a less strictly defined but more commonly used description. PCC pathogenesis is incompletely understood but involves diverse molecular and cellular mechanisms which vary between individuals.⁵³ Symptoms are similarly diverse, with the most frequent symptom clusters being shortness of breath, fatigue, and cognitive problems.⁵⁴ Most PCC cases occur following mild acute illness, and females are more frequently affected than males (OR 1.56; 95% CI:1.41–1.73). However, the risk of developing PCC is higher among individuals who experience severe acute disease.⁵⁵ Reinfection with SARS-CoV-2 has been associated with increasing the risk of PCC.⁵⁶

Estimates of the risk and prevalence of PCC vary considerably due to differences in study design, cased definitions used, time period and duration of follow-up. In this context, pooled estimates across large meta-analyses consistently range around 28–36%.⁵⁷,⁵⁸,⁵⁹ Recent evidence suggest the current incidence of PCC is lower than earlier in the pandemic.^54,60 However, continued SARS-CoV-2 transmission globally means that even lower incidence rates may result in a substantial number of PCC cases. Consequently, PCC remains an important and ongoing public health concern. COVID-19 vaccination may reduce the risk of PCC primarily through prevention of severe disease.

Other post-acute sequelae have been described following acute COVID-19 illness. These include cardiovascular and neurological events, and kidney and lung impairments. Subsequent reinfections with SARS-CoV-2 are associated with higher hazards and excess burden of these conditions.⁶¹,⁶²,⁶³

Diagnosis

Diagnosis of SARS-CoV-2 infection relies on detection of viral RNA using reverse transcription polymerase chain reaction (RT-PCR), which remains the gold standard.⁶⁴ Rapid antigen tests offer timely results and are widely used for point-of-care testing although they have lower sensitivity than RT-PCR, especially in asymptomatic individuals or early/late in the infection course.⁶⁵ Serology is useful for retrospective detection of past infection and for population-level surveillance but is not recommended for diagnosis of acute SARS-CoV-2 infection.

Treatment

Treatment of COVID-19 depends on disease severity and is summarized in WHO’s Therapeutics and COVID-19: living guideline.⁶⁶ Non-severe disease usually requires no specific treatment. Antiviral and immune-modulation therapies, including corticosteroids, may be indicated for severe disease, although availability varies depending on the geography and population. Supportive care guidelines which address non-specific therapeutic recommendations are also available.⁶⁷

Given the wide variety of PCC mechanisms, current and future PCC treatments are expected to be tailored to the underlying causes in each person. People experiencing persistent limitations in daily functioning or a protracted course of PCC will require person-centred, comprehensive and multidisciplinary rehabilitation services delivered in collaboration with primary care practitioners and several medical specialties.⁶⁸

Acquired immunity and correlate of protection

Immunity to SARS-CoV-2 is characterized by hybrid immunity resulting from multiple exposures to SARS-CoV-2 infection and/or COVID-19 vaccination.⁶⁹ Neutralizing antibody (nAb) titres are the primary correlate of protection against symptomatic infection and mild disease.⁷⁰ Compared to nAb titres, T-cell and memory B-cell responses demonstrate significantly higher cross-reactivity across drifted Omicron sub-lineages. These cellular responses are pivotal for protecting against severe outcomes, even when nAb titres are diminished against new variants with viral escape mutations.⁷¹

Public health and social measures (PHSM)

In addition to vaccination, COVID-19 prevention and control relies on a range of non-medical PHSM which range from hand hygiene, respiratory etiquette, mask use, physical distancing, ventilation of indoor spaces, testing, active case finding, contact tracing, and isolation or quarantine of infected individuals. To ensure that populations are not unnecessarily exposed to unintended health and socioeconomic consequences of PHSM implementation, the reliance and intensity of PHSM need to be continuously reviewed and adjusted based on the availability of medical countermeasures, population immunity, health system capacity and public acceptance. The reliance on PHSM relative to medical countermeasures, was particularly important in the absence of widespread immunity⁷¹, prior to COVID-19 vaccine availability, and during surges associated with new variants. PHSM have also had collateral benefits in reducing the transmission of other respiratory pathogens.⁷²

COVID-19 vaccines

During the PHEIC, WHO recommended 13 ancestral strain COVID-19 vaccines across four platforms: inactivated, mRNA, protein subunit, and viral-vector. As manufacturers transitioned from EUL to full WHO prequalification, only mRNA and protein subunit COVID-19 vaccines platforms have been updated to Omicron-adapted formulations (XBB.1.5, JN.1, KP.2, LP.8.1).⁷³ Inactivated and viral-vector vaccines are no longer manufactured and were consequently delisted by WHO.⁷⁴

A combination seasonal influenza and COVID-19 mRNA vaccine has been licensed in 2026.⁷⁵

The WHO Technical Advisory Group on COVID-19 Vaccine Composition (TAG-CO-VAC) closely monitors the genetic and antigenic evolution of SARS-CoV-2 variants, immune responses to SARS-CoV-2 infection and COVID-19 vaccination, and the performance of COVID-19 vaccines against circulating variants. On the basis of these evaluations, WHO advises vaccine manufacturers and regulatory authorities twice a year on the implications for future updates to COVID-19 vaccine antigen composition.⁷⁶

During the acute phase of the pandemic, 99% of the countries worldwide deployed COVID-19 vaccines. Since 2020 through to the end of 2025, more than 13 billion COVID-19 vaccine doses have been administered globally. By the end of 2023 approximately 67% of the global population had completed a primary vaccination series and 32% of the global population received at least one booster dose of a COVID-19 vaccine.¹⁵

Demand for the COVID-19 vaccine has been falling rapidly since its peak in 2021 (11.3 billion doses). Indicatively, the number of COVID-19 vaccine doses purchased globally dropped from approximately 700 million in 2024 to approximately 200 million in 2025, a 3.5-fold decline. At the same time, the number of suppliers declined from 24 to 16 over the same period. Volumes are currently largely driven by high-income countries following a sharp decline in demand in low‑ and middle‑income countries in 2025. At the product level, mRNA platforms dominated the market, accounting for more than 90% of the global volumes in 2025.⁷⁷

In 2025, 133 of WHO’s 194 Member States reported targeting at least one population group with COVID-19 vaccines. Primary vaccination most commonly was targeted to older adults (65%), followed by older adults with chronic conditions (58%), health and care workers (53%) and pregnant women (48%). COVID-19 booster vaccination showed a similar pattern.⁷⁸ Data from the same year show that COVID-19 vaccine uptake was very low in most settings.⁷⁹

Vaccine administration and storage

Licensed COVID-19 vaccines are administered intramuscularly, usually in the deltoid muscle.⁸⁰ Dosing schedules vary by product, individual age and risk profile.

Evidence from randomized clinical trials, immunogenicity studies, systematic reviews, and post-marketing surveillance supports the coadministration of COVID-19 vaccines with other routinely recommended vaccines (injected in separate sites), particularly seasonal influenza vaccines.⁸¹,⁸²,⁸³ Across studies involving diverse populations, simultaneous administration has demonstrated no clinically meaningful reductions in immune responses or vaccine effectiveness (VE), although some findings indicate small and transient increases in reactogenicity (e.g., injection-site pain, fatigue, myalgia). During pregnancy, evidence on coadministration of COVID-19 vaccines with other vaccines is limited but similarly does not indicate safety concerns or reduced VE when vaccines are administered during the same visit.⁸⁴,⁸⁵,⁸⁶

COVID-19 vaccines are available in multidose vials and prefilled syringe presentations and should be stored according to the manufacturer’s specifications. mRNA vaccines may require cold or ultra-cold chain storage up to -20°C or -80°C, and protein subunit vaccines generally require 2–8°C storage. However, storage requirements for both vaccine types ultimately depend on product-specific stability.

Interchangeability

During the COVID-19 pandemic vaccination response, both homologous (using the same vaccine product for subsequent doses) and heterologous (using different vaccine products for subsequent doses) vaccine schedules were shown to be safe and immunogenic, with no clinically meaningful differences in protection against severe disease.⁸⁷ Randomized controlled trials and systematic reviews showed that heterologous boosting elicited equal or higher nAbs and T-cell responses compared with homologous schedules, while maintaining an acceptable safety profile with no increase in serious adverse events. More recent real-world VE studies from the Omicron era further indicated comparable or improved protection against hospitalization and severe outcomes with heterologous boosting compared to homologous combinations.⁸⁸,⁸⁹

Immunogenicity, efficacy and effectiveness of COVID-19 vaccines

Variant‑adapted vaccines have been shown to elicit, on average, 40% higher nAb responses against variants emerging within one to two years of vaccine release compared with non‑adapted vaccines, with this benefit increasing cumulatively with each adapted booster dose.⁹⁰ Adapted vaccines against more recent variants (JN.1, KP.2 and LP.8.1) resulted in a clear increase of nAbs also against antigenically-drifted variants.⁹¹,⁹²,⁹³ While some recent variants such as BA.3.2.2 showed a particular escape from nAbs, T-cell reactivity generally remains high.^83,94

nAbs generally have a relatively short half-life of approximately 2–3 months, limiting the long-term protection against symptomatic infection, especially against antigenically-drifted variants, for which neutralization titres are initially lower than those observed against earlier variants.^83,95,⁹⁶

In older adults, COVID-19 vaccines elicit lower- and faster-waning nAb titres compared to younger adults, although repeated boosting narrows this gap.⁹⁷,⁹⁸ In people living with HIV, seroconversion rates and CD4 T-cell responses after booster vaccination have been shown to be comparable to those in HIV-uninfected healthy persons with stronger effects in vaccinees with high initial CD4 T-cell counts. CD8 T-cell responses were shown to be reduced in people living with HIV following booster vaccination.⁹⁹ Pregnant women have nAb responses equivalent to those in other healthy adults. nAbs against SARS-CoV2 are passed transplacentally from pregnant mothers to their fetuses, which results in higher maternal antibody titres in babies born to mothers vaccinated during pregnancy.¹⁰⁰,¹⁰¹

Vaccine efficacy from randomized clinical trials was available only for the early COVID-19 period with ancestral-strain COVID-19 vaccines, mainly assessed against the 2020–2021 pre-Omicron period when population immunity was low. Studies showed high efficacy against symptomatic disease.

Real-world evidence on vaccine effectiveness (VE) from millions of vaccinated individuals confirms the ability of vaccines to reduce COVID-19-associated severe disease and death. Effectiveness was highest in the pre-Omicron period (>80% after the primary series) but remained substantial during the Omicron period with clear added benefit from boosters in protection against severe disease and death. The more recent studies from 2024–2025 assess up-to-date or relative VE comparing individuals recently vaccinated with variant-adapted vaccines to those who have not received these vaccines, usually including individuals who have previously received earlier vaccines. Including previously-vaccinated individuals in the comparator group has the effect of lowering the VE estimates because they assess the added protection above existing immunological protection instead of comparing it to no vaccine-related protection as in earlier studies. This is programmatically useful, however, for assessing the added value of annual (or bi-annual) boosters in the current COVID-19 context. Unless otherwise specified, the evidence for VE reported below was from a recent systematic review that evaluated up-to-date or relative VE in observational studies during periods when JN.1 or later Omicron sub-lineages were predominant (≥50%) between January 2024 and December 2025.¹⁰² The review focused on evidence of VE against severe outcomes for older adults, adults with comorbidities or immunocompromising conditions, pregnant women and their infants, healthy adults and healthy children. No studies of VE against transmission among health and care workers were identified for the Omicron period.

Older adults

The above-mentioned systematic review evaluated VE in adults aged 60 years and older.⁹³ In general, VE of mRNA vaccines was moderately high against severe disease and death within 6 months of vaccination: VE against death ranged from 48% to 96% (3 studies with 6 unique VE estimates) and from 34% to 85% for severe disease (10 studies, 15 estimates); VE was lower when including studies with longer follow-up, up to approximately 11 months since vaccination (interquartile range 25–66% and 22–47%, respectively). Studies evaluated XBB.1.5 (n=9),¹⁰³ JN.1 (n=2) and KP.2 (n=6) monovalent vaccines. When restricted to comparable follow-up windows within three months of vaccination, VE was similar between XBB.1.5 and JN.1 vaccines against both death (range 48–86%, n=3; 18–83%, n=4, respectively) and severe disease (39–75%, n=3; 28–68%, n=8, respectively), which was higher than KP.2 vaccine (25–46%, n=2). However, within the same United States surveillance network, VE against death among adults aged ≥75 years for KP.2 vaccine (70%, 95%CI: 29–86) was substantially higher than for XBB.1.5 vaccine (23%, 95%CI: -1–45) assessed within approximately seven months after vaccination.¹⁰⁴,¹⁰⁵

Adults with comorbidities and immunocompromising conditions

The systematic review evaluated VE among people living with a range of conditions, including PLHIV and immunosuppressed adults with cancer, asthma, cardiovascular disease, diabetes, chronic liver disease, hypertension, lung disease or renal disease. VE against severe disease was generally similar between adults with immunocompromising conditions (6 studies) and immunocompetent adults, including 8 within-study comparisons in 4 studies (range 23–63% versus 25–54%, respectively). Those with comorbidities (3 studies, 9 estimates) had VE (range 41–58%) similar to the results above for older adults with comparable follow-up (range 4–10 months).

Pregnant women and their infants

The systematic review of pregnant women included any Omicron sub-lineages study (i.e. from BA.1 onwards), and the search extended through to 8 January 2026.¹⁰² VE of an ancestral strain mRNA vaccine booster dose against maternal hospitalization due to Omicron infection compared to unvaccinated pregnant women ranged from 43% to 97% (3 studies, 4 estimates) and compared to women vaccinated before pregnancy or several months earlier during pregnancy ranged from 34% to 92% (4 studies, 5 estimates), all conducted during the pre-JN.1 Omicron sub-lineages periods. Variation in VE was attributed to differences in comparator groups, inclusion of incidental COVID-19 infection in hospitalizations in some studies and wide confidence intervals.

VE of maternal booster vaccination against hospitalization of the women’s infants up to 6 months of age due to Omicron infection was 64% (95%CI: 52–73) and 80% (95%CI: 64–89) (2 studies) when compared to unvaccinated mothers; VE was 65% (95%CI: 32–82) when compared to mothers who received the primary series. The effect of timing of maternal vaccination during the Omicron period was evaluated only for the primary series compared to unvaccinated mothers; one study observed higher VE against infant hospitalizations when vaccines were administered ≥20 weeks of gestational age versus <20 weeks (57%, 95%CI: 25–75 versus 25%, 95%CI: -26–56), but confidence intervals were wide.¹⁰⁶ Two studies evaluated VE against infection in infants by trimester of maternal immunization, finding no association with the timing of vaccination.¹⁰⁷, ¹⁰⁸

Healthy adults

Evidence for VE in healthy adults aged 18–64 years was limited to five studies – four from the United States and one study in four western European nations. Three studies assessed XBB.1.5 vaccines and two assessed KP.2 vaccines. Only one study assessed VE against death, finding strong protection (VE 84%, CI; 21–100) at a mean of 25 weeks post-XBB.1.5 vaccination; however, confidence intervals were wide and the study population (United States military veterans aged 18–64 years) was likely to have included individuals with underlying conditions.⁹³

Two studies evaluated VE of XBB.1.5 vaccines against severe disease, finding 30% (95%CI: 3–48) and 66% (95%CI: 56–74) VE assessed at a median of approximately 25 and 15 weeks post-vaccination, respectively; however, the first study was the United States veterans study mentioned above with a high proportion with underlying conditions. KP.2 vaccine VE against severe disease was 12% (95%CI: -50–43), although with wide confidence intervals crossing 0%.^93,109

VE against symptomatic disease was 37% (95%CI: 29–44) (one study) for XBB.1.5 vaccines and around 30% (two studies) for KP.2 vaccines. Protection against infection was low, with XBB.1.5 VE estimated at 9% (95%CI: 1–15) and KP.2 VE at 22% (95%CI: 7–34), both from studies among United States veterans.

Healthy children

Only one study evaluated VE against severe disease among children, finding moderately strong protection in United States children aged 5–17 years with an XBB.1.5 mRNA booster dose (VE 65%, 95% CI 36–81%) at a median of approximately 11 weeks post-vaccination.¹¹⁰ VE was similar between younger children (5–11 years, VE 68%) and adolescents (12–17 years, VE 63%). No study assessed VE against death.

Four VE estimates against symptomatic disease from two United States studies of children aged 9 months to 17 years observed 35% (95%CI: 16–49) and 44% (95%CI: 29–55) VE for XBB.1.5 vaccines and 56% (95%CI: 35–70) and 66% (95%CI: 51-76) VE for KP.2 vaccines.¹¹¹,¹¹² The KP.2 study had shorter maximum follow-up times (~26 weeks) than the XBB.1. study (~47 weeks), which may explain the higher VE, although median follow-up times differed only modestly (~11 versus ~13 weeks). No substantial age-related differences in VE were observed.

Vaccine efficacy against post-COVID-19 condition and long COVID-19

A systematic review and meta-analysis assessed the effectiveness of COVID-19 vaccination against PCC as the primary outcome and LC as a secondary outcome. The review included 89 studies published between 1 January 2020 and 1 August 2024. Overall, receipt of at least one vaccine dose prior to SARS-CoV-2 infection was associated with a pooled VE of 41.0% (95% CI: 28.8–51.1; 22 studies) against PCC compared with no vaccination. The analysis also found that protection increased with the number of vaccine doses received before infection. Among studies comparing two doses with no vaccination, VE against PCC was estimated at 32.1% (95% CI: -54.3–70.1; 3 studies) during the pre-Omicron period, and at 20.9% (95% CI: -10.2–43.3; 2 studies) during the Omicron period.¹¹³ Another systematic review and meta-analysis evaluated the impact of COVID-19 vaccination, including booster doses, on the prevention of LC (any definition) following Omicron variant infection. The review included 31 studies published between 1 January 2022 and 1 March 2024. Compared with unvaccinated individuals, receipt of any COVID-19 vaccine dose was associated with a reduced risk of LC (pooled OR: 0.77; 95% CI: 0.70–0.85; 10 studies). Similarly, receipt of a booster dose was associated with a lower risk of LC compared with completion of the primary vaccination series alone (pooled OR: 0.77; 95% CI: 0.65–0.92; 3 studies). ¹¹⁴

In both cases, sensitivity analyses supported the robustness of the findings and did not suggest the presence of significant publication bias. These results indicate that COVID-19 vaccination, including booster doses, may provide additional protection against PPC and LC following Omicron variant infection, although estimates varied across studies.

Impact of COVID-19 vaccination on mortality

All available studies assessing the impact of COVID-19 vaccination are consistent in showing that COVID-19 vaccination has reduced global mortality. However, published models vary in methodology, time horizon and key assumptions regarding infection fatality ratios and VE, with some resulting in widely divergent estimates. The most conservative model estimated 2.5 million deaths averted between 2020 and 2024.¹¹⁵ This model used a non-dynamic framework, meaning that the authors applied fixed assumptions to global age strata. By design, the model used a fixed attack rate that was not derived from epidemic dynamics and therefore could not account for any transmission reduction and was arguably overly conservative for a no-vaccine counterfactual. Furthermore, the model used time-invariant infection fatality ratios and VE assumptions that were lower than those used in most other models. In contrast, a dynamic transmission model, which relied on early pandemic fatality values and optimistic assumptions about vaccine-induced transmission reduction, estimated that COVID-19 vaccination prevented about 14.4 million deaths in the first year of use.¹¹⁶ Extending this analysis to incorporate updated evidence on lower Omicron infection fatality ratios, waning VE and the accumulation of hybrid immunity,¹¹⁷,¹¹⁸ a revised model suggests that COVID-19 vaccination averted some 19.5 million deaths (95% uncertainty interval 17.4–22.3 million) globally between 2020 and 2024 across 191 WHO Member States (excluding China¹¹⁹).¹²⁰ A retrospective surveillance analysis from 33 countries in the WHO European Region estimated 1.7 million lives saved by direct COVID-19 vaccine impact alone between December 2020 and March 2023.¹²¹ The extended analysis for the same countries over the same time frame estimates 3.2–3.9 million lives saved, accounting for both direct and indirect vaccine impact.¹²²

Duration of protection

A previous systematic review and meta-analysis during the early Omicron period found that absolute VE of booster doses against severe disease remained high but waned 8.2 percentage points by 6 months and was restored with subsequent doses.[^123] For symptomatic disease and infection, the degree of waning was greater, with essentially no protection against infection 6 months after the last dose. In the environment of JN.1 and related sub-lineages when almost everyone had some protection either through previous vaccination or prior infection, additional vaccine doses improved protection in the months after vaccination. However, VE against severe disease waned more rapidly than in the early Omicron period, with little to no vaccine protection remaining by 6 months after vaccination among high-risk persons, including older adults, immunocompromised or with comorbidities.

Safety of COVID-19 vaccines

More than five years of accumulated COVID‑19 vaccine safety data from clinical trials, post‑marketing pharmacovigilance systems, and international regulatory reviews have shown a favourable safety profile for COVID-19 vaccines. The WHO Global Advisory Committee on Vaccine Safety (GACVS) has consistently reaffirmed that the benefits of vaccination outweigh the risks across all groups – particularly in preventing severe disease, hospitalization and death among populations at elevated risk of severe COVID-19 disease.¹²³,¹²⁴ Serious adverse events remain extremely rare relative to the more than 13 billion doses administered globally. Most reactions reported are mild or moderate and transient, resolving within a few days. They typically involve local pain, redness and swelling at the injection site, fatigue, muscle and joint pain, or low-grade fever.

Causal associations¹²⁵ have been established for a several specific conditions: Guillain-Barré syndrome¹²⁶,¹²⁷ and thrombosis with thrombocytopenia syndrome following vaccination, also known as vaccine-induced immune thrombotic thrombocytopenia, with adenoviral vector COVID-19 vaccines;¹²⁸,¹²⁹ and myocarditis and pericarditis following vaccination with mRNA COVID-19 vaccines. For myocarditis and pericarditis, vaccine-attributable risk was highest among males aged 12–29 years, particularly after the second dose of COVID-19 vaccine, and substantially lower following booster doses. Reported incidence varies by age, sex, vaccine product and dose number, as well as by surveillance system. ¹³⁰,¹³¹,¹³²,¹³³,¹³⁴,¹³⁵ Longer dosing intervals (≥6 months) are associated with substantially lower risk.¹³⁶,¹³⁷ Most cases occurred within the first week after vaccination and were mild, required short hospital observation and resolved with conservative management, with good short-term outcomes.¹³⁸ More recent population-based studies that formally assessed vaccine-attributable risk, accounting for background incidence, have no longer identified an increased risk of myocarditis associated with variant-adapted mRNA COVID-19 vaccines in the populations studied.¹³⁹

For protein subunit COVID-19 vaccines, rare cases of myocarditis and pericarditis have been identified as safety signals in post-authorization surveillance and manufacturers’ periodic safety update reports. The analyses that are available suggest that the risk of these adverse events is not higher than that observed with mRNA vaccines, but precise estimates of vaccine-attributable risk are not available. Some studies using protein subunit COVID-19 vaccines indicate modestly lower rates of systemic and local adverse events post-vaccination compared to mRNA COVID-19 vaccines.¹⁴⁰,¹⁴¹ However, evidence remains more limited for protein subunit vaccines than for mRNA COVID-19 vaccines due to more limited use of protein subunit COVID-19 vaccines.¹⁴²

For other reported conditions, including stroke, myocardial infarction, ¹⁴³ infertility, ¹⁴⁴ Bell’s palsy, autoimmune disorders, and persistent menstrual changes,¹⁴⁵, ¹⁴⁶ the available evidence has not established a causal association with COVID-19 vaccination. ¹⁴⁷,¹⁴⁸ For some very rare conditions, such as capillary leak syndrome, the available evidence remains insufficient to determine whether a causal relationship exists.¹⁴⁹

Safety data following repeated doses, including revaccination with variant-adapted COVID-19 vaccines, remains reassuring, with no new safety signals identified.^149,150 ,¹⁵¹

Immunocompromised

A large United Kingdom-based study including organ transplant recipients and patients on immune-modifying therapies found no significant association between COVID-19 vaccination and idiopathic thrombocytopenic purpura, ischemic stroke or hemorrhagic stroke in the 28 days after vaccination.¹⁵² Data on the safety of protein subunit COVID-19 vaccines in immunocompromised populations remain limited. However, no specific safety concerns have been identified in the studies conducted to date.

Pregnant and breastfeeding women and their infants

Updated evidence from observational studies, pregnancy registries and vaccine surveillance systems across multiple countries have not identified safety concerns associated with COVID-19 vaccination during pregnancy.^124,153,¹⁵⁴,¹⁵⁵,¹⁵⁶,¹⁵⁷ The GACVS¹²⁹ concluded that current evidence shows no increased risk of adverse maternal or pregnancy-related outcomes, including miscarriage, stillbirth, preterm birth or adverse outcomes in infants born to persons vaccinated during pregnancy.

No safety concerns have been identified for breastfeeding women or their breastfed infants following COVID-19 vaccination.¹⁵⁸,¹⁵⁹

Cost–effectiveness of COVID-19 vaccination

A scoping review identified 21 economic evaluations of annual adapted COVID-19 vaccination published during the COVID-19 endemic period (2023 onwards), showing that cost-effectiveness is well demonstrated for older adults while cost-effectiveness decreases for younger, healthy populations.¹⁶⁰ Results were geographically concentrated in high-income countries, limiting generalizability, and about half of studies had industry funding. Among older adults, cost‑effectiveness was greater with increasing age and among those with comorbidities, with lower numbers needed to vaccinate in the oldest age groups compared to younger groups. For people with comorbidities or immunocompromised, vaccination was generally cost-effective although still age-dependent. Limited evidence suggests that vaccination of health workers may be cost-saving in high-exposure environments. Vaccination of healthy adults and children was generally unfavourable at standard cost-effectiveness thresholds. No studies reported on the cost-effectiveness of vaccinating in pregnancy from 2023 onwards. Broader vaccination strategies may be cost-effective in certain contexts, depending on the disease burden and disruptions to economic activity, COVID-19 vaccine price and programmatic factors.

Programmatic and health system considerations

The deployment of COVID-19 vaccines represented an unprecedented global effort implemented at scale under extraordinary pressure during a global health crisis. This response strengthened immunization systems, including cold chain capacity, digital data systems and delivery approaches to adult immunization.¹⁶¹

Vaccine acceptance evolved substantially throughout the pandemic. It was high during the initial rollout in 2021 as evidence on vaccine safety and effectiveness accumulated but became increasingly heterogeneous from 2022 onwards across both countries and population groups. A review¹⁶² of 13 studies published in late 2025 and conducted between 2023 and 2025 found that acceptance was primarily influenced by perceived risk of severe disease, confidence in vaccine safety, effectiveness and benefit, trust in health-care providers, and social influences – including reliance on online information. Acceptance remained generally higher among individuals with comorbidities, whereas lower acceptance was observed among healthy adults.

The COVID-19 vaccination experience highlighted the importance of a life-course approach to immunization, particularly for older adults and other high-risk groups. Embedding adult immunization within national immunization strategies and primary health-care systems can strengthen the resilience of immunization programmes, supporting more effective routine delivery as well as pandemic preparedness and response, making an important contribution to health security.¹⁶³

WHO position

Rationale for routine COVID-19 vaccination

The current epidemiology, extensive COVID-19 vaccine safety and effectiveness record, and available cost-effectiveness evidence support routine COVID‑19 vaccination, particularly for groups at higher risk of severe COVID‑19 outcomes. Until more data are available, COVID-19-related severe disease and deaths remain the outcomes of interest that should be driving decision-making on COVID-19 vaccination while those vaccinated may benefit from the moderate VE against PCC.

Routine, periodic COVID-19 vaccination helps to sustain protection as immunity acquired through vaccination wanes over time, with limited protection beyond 6 months following the most recent vaccine dose.

WHO recommends that countries consider routine COVID-19 vaccination based on local COVID-19 epidemiology, population characteristics (including the prevalence of groups at higher risk of severe COVID-19 disease), access to COVID-19 vaccines, cost-effectiveness, acceptability, and programmatic feasibility.

Target groups for vaccination

Countries should consider routine COVID-19 vaccination for those groups at highest risk of severe COVID-19 disease, whether previously vaccinated (last dose more than 6 months previously) or unvaccinated, as follows:

• oldest adults, with the age threshold determined by countries (suggested at 75 or 80 years of age);

• older adults, with the age threshold determined by countries (suggested at 60 years of age) for those with significant comorbidities or severe obesity, with the thresholds determined by countries (significant comorbidities include chronic cardiovascular disease, diabetes mellitus, chronic respiratory disease, chronic kidney disease, chronic liver disease and neurological conditions);

• residents in care homes for older adults with the age threshold determined by countries (suggested at 60 years of age) and those in long-term care facilities; and

• moderately or severely immunocompromised individuals (Table 1) from 6 months of age, including those with active cancer or immunodeficiencies, transplant recipients and those being treated with immunosuppressives (also including people living with HIV with a CD4 T-cell count of <350 cells µl, or with evidence of an opportunistic infection, or not on HIV treatment, or with a detectable viral load).

Countries may consider routine COVID-19 vaccination of additional groups, whether previously vaccinated (last dose more than 6 months ago) or unvaccinated, on the basis of local context, cost-effectiveness and programmatic feasibility. These groups include:

• older adults with the age threshold determined by countries (suggested at 60 years of age) without significant comorbidities or without severe obesity;

• adults (not included in the older adult category), adolescents and children with significant comorbidities or severe obesity;

• pregnant adolescents and adults (vaccination during pregnancy aims to protect against maternal severe COVID-19, to prevent COVID-19-associated adverse pregnancy outcomes, and to protect the infant during the first months of life through maternal antibody transfer);

• health workers and other care providers, who have direct contact with persons at high risk of severe COVID-19, such as staff of public and private health and social care establishments and co-habitants or caregivers of persons who are at highest risk of severe COVID-19 disease); and

• previously unvaccinated healthy children (6 months to 23 months of age) only in countries with documented significant burden in this age group.

The WHO recommendations for routine COVID-19 vaccination are summarized in Table 2.

Vaccine choice, administration and dosing

Based on age and vaccine availability, either an mRNA variant-adapted (for those 6 months of age and older) or protein subunit variant-adapted COVID-19 vaccine (for those 12 years of age and older) can be used in unvaccinated or previously vaccinated individuals who do not have contraindications to the vaccine.

WHO recommends that countries determine the optimal timing for offering COVID-19 vaccination on the basis of local COVID-19 epidemiology and the feasibility of vaccine delivery. While currently no consistent seasonal pattern has been established for COVID-19, co-administration (injected in separate sites) of the COVID-19 vaccine with seasonal influenza vaccine (where applicable) or with other vaccines targeting the same population groups may improve programmatic uptake. This approach can enhance convenience, and therefore access, reduce the number of vaccination visits and reduce programmatic costs.

WHO recommends a preferred routine interval of approximately 6 months between COVID-19 vaccine doses. However, shorter intervals may be considered when clinically indicated. For individuals who have had test-confirmed SARS-CoV-2 infection who are due for a recommended COVID-19 vaccine dose, an interval of approximately 6 months after infection may be considered.

For groups at highest risk of severe COVID-19 disease, WHO recommends at least one COVID-19 vaccine dose per year – preferably two, about 6 months apart – due to the relatively rapid waning of immunity and limited protection beyond 6 months after the last dose. Country decisions on the number of doses per year (one or two) for those at highest risk and for additional groups should take into consideration cost-effectiveness and programmatic feasibility.

WHO recommends that breastfeeding women at higher risk of severe COVID-19 be vaccinated according to the same recommendations that apply to other individuals in their risk group.

For pregnant adolescents and adults, WHO recommends one COVID-19 vaccine dose in each pregnancy at any stage – ideally during the second trimester. The aim is to optimize protection against maternal severe COVID-19, prevent adverse pregnancy outcomes, and protect the infant during the first months of life.

For previously unvaccinated children aged 6–23 months, the number of doses required for primary COVID-19 vaccination depends on the vaccine product used and is typically two or three doses. Revaccination is not routinely recommended for this group.

Coadministration

COVID-19 vaccines may be given concurrently with, or at any time before or after, other vaccines. The same applies to maternal immunization for vaccines recommended during pregnancy.

When administered concomitantly, the vaccines should be injected in separate sites, preferably in different extremities.

Interchangeability

Different COVID-19 vaccine products or types can be used for subsequent doses.

Contraindications

Individuals with a history of anaphylaxis after a previous dose of a COVID-19 vaccine, or a component of that vaccine, should not receive additional doses of the same COVID-19 vaccine type. For subsequent doses, an alternative COVID-19 vaccine type may be administered.

In individuals with a history of myocarditis or pericarditis following a previous COVID-19 vaccine dose, the decision to administer subsequent doses should be based on an individual risk–benefit assessment.

Fragile, conflict-affected and vulnerable settings

Countries may consider COVID-19 vaccination for those at high risk of severe COVID-19 in fragile, conflict-affected and vulnerable settings in the context of the epidemiological setting, COVID-19 vaccine availability and overall priorities.

WHO has developed a framework¹⁶⁴ and tool to assist in deliberately, ethically and rationally determining whether the delivery of one or more vaccines to specific target populations during humanitarian emergencies would result in an overall saving of lives and a reduction in the population’s burden of disease.

Travellers

Travellers should not be considered a population group intrinsically at higher risk of severe COVID-19. However, travel may increase exposure to – and therefore infection with – SARS-CoV-2, especially in crowded settings or during mass gatherings. COVID-19 vaccination of travellers at high risk of developing severe COVID-19 disease may be considered on the basis of the epidemiological setting and country-specific COVID-19 vaccination recommendations.

Surveillance and monitoring

WHO recommends integrating SARS-CoV-2 surveillance into established influenza-like illness and severe acute respiratory infection sentinel surveillance systems to support coordinated monitoring of respiratory pathogens.¹⁶⁵ COVID-19 surveillance data should guide countries in determining priorities for routine COVID-19 vaccination, including the identification of population groups at increased risk of severe disease.

Continued post-marketing pharmacovigilance for COVID-19 vaccines, including studies in pregnancy and event monitoring in other cohorts, remains essential for the timely detection and evaluation of emerging safety signals and for maintaining public confidence in immunization programmes.

Countries are expected to monitor COVID-19 vaccination and report it annually through the electronic WHO-UNICEF Joint Reporting Form (eJRF), in line with reporting for other vaccines included in national immunization programmes.¹⁶⁶

Research priorities

• Development of pan-sarbecovirus or universal coronavirus vaccines with broader and longer-lasting protection, as well as COVID-19 or combination vaccines with greater impact on virus transmission (e.g. vaccine platforms that elicit strong mucosal immunity).¹⁶⁷

• Continuous monitoring of the epidemiology of COVID-19, including SARS-CoV-2 variants/sub-lineages and seasonal trends, to inform future timing for COVID-19 vaccination.

• Further analyses of the comparative morbidity, including PCC, and mortality risk for COVID-19, influenza and other respiratory viruses derived from observational studies.

• Establishing correlates of protection and standardized immunological assays for COVID-19 vaccines.

• Further assessment of COVID-19 severity in pregnancy and in infants (<6 months), and of the need for vaccination in each pregnancy.

• Continuous monitoring of COVID-19 VE, including for variant-adapted vaccines, particularly in populations at high risk of severe outcomes.

• Rigorous assessment of the burden, societal impact and vaccine effectiveness against PCC utilizing the WHO standardized definition.¹⁶⁸

• Further assessment of cost-effectiveness, particularly in low‑ and middle‑income countries and among groups such as health and care workers and children.

• Understanding social and behavioural drivers of COVID-19 vaccines to address hesitancy and guide interventions to achieve high confidence and uptake.