Although influenza vaccine had been marketed for many years as being 70-90% effective in healthy adults, it is now generally accepted that effectiveness lies in the range 50-70%. A five year study in Victoria estimated vaccine effectiveness (VE) against laboratory-confirmed influenza for adults aged 20-64 years seen by sentinel general practitioners in the community as 62%. Effectiveness may be lower in older people and in people who are hospitalised.
Australia is considering a universal vaccination program for children. The US already funds annual influenza vaccination for all children and the UK will introduce live attenuated influenza vaccine (LAIV) for children aged 2-17 years from 2014. LAIV is not licensed in Australia and any program for vaccinating children in this country would rely on trivalent inactivated vaccine (TIV) or the newer quadrivalent inactivated vaccine (QIV). A five year program in Western Australia has confirmed the effectiveness of TIV in healthy children aged 6-59 months, with VE estimated as approximately 65% for 2008-12, excluding the pandemic year of 2009. However community confidence in influenza vaccines for children was dented in 2010 when vaccines manufactured by BioCSL, but not other manufacturers, were shown to be responsible for a dramatic increasing in febrile reactions, including febrile seizures.
Health care worker vaccination is not universally funded but is often funded by the workplace. Lively debate continues about compulsory influenza vaccination for health care workers.
A recent WHO report acknowledged poor levels of evidence for many current influenza vaccine programs but recommended pregnant women should be targeted for vaccination in new or existing programs. Vaccine uptake by pregnant women in Australia is poor.
Unresolved issues about influenza vaccine effectiveness and uptake remain to be resolved.