WHO review of bacterial vaccines in development for priority drug-resistant pathogens

Published: July 2022

WHO analysed the pipeline of bacterial vaccines that were in Phase I–III of clinical development or in preclinical development (as of September 2021) and matched these against the WHO priority pathogens list (PPL) for antimicrobial-resistant (AMR) pathogens and the pathogens Mycobacterium tuberculosis and Clostridioides difficile.

Candidate vaccines are reported by stage of development, pathogen category, pathogen targeted, vaccine approach, whether the vaccine targets multiple pathogens, whether the vaccine is prophylactic or therapeutic, administration route, and characteristics of the vaccine developer. See below for details on the scope, analysis, limitations and data source. 

See also:

Health products in the pipeline from discovery to market launch for all diseases
WHO review of antibacterial agents in clinical development
WHO review of antibacterial agents in preclinical development

What you see | Scope, analysis and limitations | Data sources 

What you see

The data visualization shows the numbers of antibacterial products by:

  • stage of development (chart A);
  • category of pathogen targeted (chart B);
  • pathogen targeted (chart C);
  • phase of development, by stage and status (chart D);
  • vaccine approach in terms of technology platform used (chart E);
  • whether the vaccine targets multiple pathogens (chart F);
  • whether the vaccine is prophylactic or therapeutic (chart G);
  • route of administration (chart H);
  • characteristics of vaccine developers (charts I).

Chart J shows vaccine candidates listed by activity status, approach, and stage of development with further information on each product (hover on the phase to open a popup window for additional information) (chart J).

Products can also be viewed according to activity status (select status options using top left tick boxes).

Points to note:
  • As of September 2021, a total of 155 candidate vaccines targeting the WHO priority pathogens or M. tuberculosis, and C. difficile are in active clinical (61) and preclinical (94) stages of development (select the “Active” status tick box at the top left and view chart A).
  • Of the 61 candidate vaccines in an active status of clinical development (Select the “Active” status tick box at the top left and then click on “Clinical” in chart A):
  • 10 candidate vaccines target “critical” priority pathogens (chart B).
  • Except for Enterococcus faecium and Enterobacter spp, all the pathogens on the bacterial priority pathogens list, as well as C. difficile and M. tuberculosis, were targeted by a candidate vaccine (chart C).
  • The most common pathogen targeted by candidate vaccines is Streptococcus pneumoniae (26%; 16).
  • The majority of candidate vaccines are in Phase II of development (43%; 26); 30% (18) are in Phase III and 28% (17) are in Phase I of development (chart D).
  • A conjugate (subunit) approach is the most common approach: almost 40% (24) of candidates use this approach (chart E).
  • The majority of candidate vaccines (90%; 55) target a single pathogen (chart F).
  • The majority of candidate vaccines (84%; 51) are for prophylactic use (chart G).
  • 31 of the 40 vaccine candidates with a known route of administration are parenteral (chart H).
  • Almost two-thirds (62%; 38) of lead developers are from the private sector, followed by public private partnerships (20%; 12) (chart I.2). 
  • Most lead developers are from high-income countries (chart I.3). 
  • There are far fewer lead developers from the WHO South-East Asia Region than from other WHO regions (chart I.4).

To explore the data further

  • Select activity status, pathogen category, pathogen, phase of development or other element – or a combination of elements (e.g., by clicking on a bar in a chart or a cell in a table) – to display the corresponding data in the other charts.
  • Hover the cursor on a bar, a slice in a pie or a cell in a table to see more information in a popup window.
  • Hold the ‘Ctrl’ key on your keyboard to select more than one option.
  • Undo a selection by clicking ‘undo’ or ‘reset’ near the bottom of the page or by clicking the same element again.

Scope, analysis and limitations of the data

Scope

  • This pipeline analysis focuses on vaccines under development targeting WHO priority pathogens list for AMR, M. tuberculosis and C. difficile. It covers information available as of September 2021 and is limited to products in Phases I–III of clinical development or in late-stage preclinical development.
  • Vaccine candidates in clinical development Phases I–III with an activity status of active or inactive/discontinued, for which development had occurred in the last 10 years, were included in the analysis. The candidate status was categorized active if: any activity had taken place in the last three years; they were listed on the developer’s list as active; or they were confirmed to be in an active stage by consulted experts. Vaccine candidates were considered inactive if no evidence of activity had been identified in the last three years or if experts identified them as inactive.
  • Novel adjuvants, dosing regimens or new combinations were not considered.
  • Candidates in the preclinical phases were considered if they are in late stages of development.
  • Monoclonal antibodies or candidates for passive immunization were not included in this analysis; however, these are captured in the WHO antibacterial preclinical pipeline report.

Analysis

Data collection involved the following sources:
  • Clinical trials registries: the International Clinical Trials Registry Platform (ICTRP), clinicaltrials.gov, Japanese and Russian clinical trials databases (searched in their local languages) and industry repositories of clinical trials.
  • Status of health products in the pipeline from the WHO Global Observatory on Health Research and Development, based on Springer Nature AdisInsight data source.
  • A literature review of peer-reviewed and grey literature.
  • A draft report of products in clinical and preclinical development that was developed by WHO and shared for feedback with stakeholders from industry, academia, funding agencies, policymakers, and other experts. Comments were reviewed and incorporated into the final analysis and report.

Limitations of the data

  • This analysis relies on data available in the public domain or from contacted experts.
  • The review of products in the preclinical stage is not exhaustive.
  • It was not possible to identify up-to-date information on some vaccine candidates.

The WHO Secretariat welcomes additional information and/or feedback on the data presented in this analysis. Feedback should be sent to antibacterialpipeline@who.int.