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

WHO has identified several conditions which are associated with elevated risk of complications from seasonal influenza virus infection. These groups include pregnant women, children aged 6–59 months, the elderly, individuals with specific chronic medical conditions, and health-care workers. Against seasonal influenza there are numerous licensed vaccines available. 

Several of the influenza vaccines available have been prequalified by the WHO for purchase by UN agencies (https://extranet.who.int/pqweb/vaccines/prequalified-vaccines). This process of vaccine prequalification provides independent opinion and advice on the quality, safety, and efficacy of vaccines. There are also several vaccine candidates under development against animal influenza viruses.