Global Alert and Response (GAR)

WHO recommendations on pandemic (H1N1) 2009 vaccines

Pandemic (H1N1) 2009 briefing note 2

On 7 July 2009, the Strategic Advisory Group of Experts (SAGE) on Immunization held an extraordinary meeting in Geneva to discuss issues and make recommendations related to vaccine for the pandemic (H1N1) 2009.

SAGE reviewed the current pandemic situation, the current status of seasonal vaccine production and potential A(H1N1) vaccine production capacity, and considered potential options for vaccine use.

The experts identified three different objectives that countries could adopt as part of their pandemic vaccination strategy:

  • protect the integrity of the health-care system and the country's critical infrastructure;
  • reduce morbidity and mortality; and
  • reduce transmission of the pandemic virus within communities.

Countries could use a variety of vaccine deployment strategies to reach these objectives but any strategy should reflect the country’s epidemiological situation, resources and ability to access vaccine, to implement vaccination campaigns in the targeted groups, and to use other non-vaccine mitigation measures.

Although the severity of the pandemic is currently considered to be moderate with most patients experiencing uncomplicated, self-limited illness, some groups such as pregnant women and persons with asthma and other chronic conditions such as morbid obesity appear to be at increased risk for severe disease and death from infection.

Since the spread of the pandemic virus is considered unstoppable, vaccine will be needed in all countries. SAGE emphasized the importance of striving to achieve equity among countries to access vaccines developed in response to the pandemic (H1N1) 2009

The following recommendations were provided to the WHO Director-General:

  • All countries should immunize their health-care workers as a first priority to protect the essential health infrastructure. As vaccines available initially will not be sufficient, a step-wise approach to vaccinate particular groups may be considered. SAGE suggested the following groups for consideration, noting that countries need to determine their order of priority based on country-specific conditions: pregnant women; those aged above 6 months with one of several chronic medical conditions; healthy young adults of 15 to 49 years of age; healthy children; healthy adults of 50 to 64 years of age; and healthy adults of 65 years of age and above.
  • Since new technologies are involved in the production of some pandemic vaccines, which have not yet been extensively evaluated for their safety in certain population groups, it is very important to implement post-marketing surveillance of the highest possible quality. In addition, rapid sharing of the results of immunogenicity and post-marketing safety and effectiveness studies among the international community will be essential for allowing countries to make necessary adjustments to their vaccination policies.
  • In view of the anticipated limited vaccine availability at global level and the potential need to protect against "drifted" strains of virus, SAGE recommended that promoting production and use of vaccines such as those that are formulated with oil-in-water adjuvants and live attenuated influenza vaccines was important.
  • As most of the production of the seasonal vaccine for the 2009-2010 influenza season in the northern hemisphere is almost complete and is therefore unlikely to affect production of pandemic vaccine, SAGE did not consider that there was a need to recommend a "switch" from seasonal to pandemic vaccine production.

WHO Director-General Dr Margaret Chan endorsed the above recommendations on 11 July 2009, recognizing that they were well adapted to the current pandemic situation. She also noted that the recommendations will need to be changed if and when new evidence become available.

SAGE was established by the WHO Director-General in 1999 as the principal advisory group to WHO for vaccines and immunization. It comprises 15 members who serve in their personal capacity and represent a broad range of disciplines from around the world in the fields such as epidemiology, public health, vaccinology, paediatrics, internal medicine, infectious diseases, immunology, drug regulation, programme management, immunization delivery, and health-care administration.

Additional participants in the SAGE meeting included members of the ad hoc policy advisory working group on influenza A(H1N1) vaccine, chairs of the regional technical advisory groups and external experts. Observers included industry representatives and regulators who did not take part in the recommendation process in order to avoid conflicts of interest.

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