Influenza vaccine

Influenza vaccine development


Influenza is an acute respiratory disease that affects the upper and/or lower tract and is caused by influenza virus, usually of A or B. Influenza circulates continuously, causing seasonal epidemics in temperate regions and year-round epidemics in some tropical regions. Influenza viruses are continuously changing, necessitating annual change in vaccine strains to raised match with currently circulating influenza strains globally. Influenza A viruses can also cause pandemics characterized by rapid dissemination of a replacement , virulent influenza A subtypes to which there’s little or no existing immunity.

Status of vaccine development


Immunization is that the major public health measure for the prevention of influenza viral infection . There are numerous licensed seasonal influenza vaccines available, several of which are prequalified by the WHO for purchase by UN agencies . There also are several vaccine candidates under development against animal influenza A viruses – influenza strains considered at greatest risk for causing a future pandemic.

For WHO, the event of vaccines against influenza viruses with pandemic potential, also as seasonal influenza vaccines that induce broadly protective and long-lasting immune responses are high priorities.

Challenges to vaccine development


Due to the constant changing of circulating influenza viruses, influenza vaccines strains are changed annually (for both the hemisphere and therefore the Southern Hemisphere) to more closely match currently circulating virus strains.

WHO research activities


The Initiative for Vaccines Research (IVR) sets the influenza vaccine agenda and monitors research on new vaccines, related technologies and implementation strategies so as to get information for policy recommendations.

Specific areas of focus

Research and evaluation of seasonal and pandemic influenza vaccines, including cost effectiveness analyses, technical and regulatory issues regarding supply and demand of influenza vaccines, and influenza vaccines effectiveness studies


Research on optimized implementation handling obstacles in seasonal influenza immunization and mathematical modelling for influenza vaccine impact

Summarising clinical evaluation data on safety, immunogenicity and efficacy/effectiveness of influenza vaccines
Providing technical information for policy makers, including WHO influenza position papers and seasonal influenza vaccine recommendations