On 13 May 2022, WHO published an updated position paper on the use of seasonal influenza vaccines.
In December 2017, following a request by WHO’s Strategic Advisory Group of Experts on Immunization (SAGE), an influenza working group was convened to review the scientific evidence and relevant programmatic considerations on seasonal influenza vaccines and assess whether the existing (2012) WHO position paper on this topic should be updated. Based on this review, the working group proposed a set of recommendations for SAGE to consider at its meeting in October 2021.
These recommendations are reflected in the updated influenza vaccines position paper. WHO continues to recommend that all countries implement seasonal influenza vaccination programmes based on the burden and epidemiology of influenza, cost-effectiveness of vaccination, competing public health priorities, and programmatic feasibility.
Changes from the previous influenza vaccines position paper include:
- Countries looking to start or expand seasonal influenza vaccination programmes should consider prioritizing the following target groups (in no particular order): health workers, individuals with comorbidities and underlying conditions, older adults, and pregnant individuals. Children continue to be an important target group, and countries may consider them as a priority group based on national disease goals, capacities and resources, and epidemiology and disease burden.
- There are multiple new and advanced influenza vaccine products and formulations that are approved and are effective and safe in specific populations. For settings with limited resources, WHO recommends that countries aim to achieve maximum population impact, which may be most equitably achieved using traditional, less expensive influenza vaccines that are more widely available.
- While quadrivalent influenza vaccines may potentially provide greater protection, especially during seasons with higher circulation of influenza B, countries should establish context-specific decision-making processes to determine whether the potential health gains outweigh the costs for transitioning from trivalent to quadrivalent influenza vaccines.
- Evidence on repeat immunization shows that vaccination in the current and prior season provides better (if somewhat attenuated) protection than only being vaccinated in the prior season, or not being vaccinated at all. WHO continues to recommend annual influenza vaccination before the influenza season begins.
- Co-administering seasonal inactivated influenza vaccines and any dose of a COVID-19 vaccines is acceptable and may increase programme efficiency.
- Research priorities have been noted in vaccine development and manufacturing, immunologic evidence, vaccine efficacy and effectiveness among target groups, vaccine impact models, and implementation research.