A new generation of more effective flu vaccines is “urgently needed” to prevent widespread illness and death, it has been claimed.
Scientists who analysed 40 years of data concluded that current vaccines offered inadequate protection against both seasonal influenza outbreaks and serious pandemics.
Evidence for their effectiveness in older individuals was also lacking, said the researchers who pooled the results of 31 studies published over four decades.
Overall, the most widely used seasonal flu vaccine, known as trivalent inactivated vaccine (TIV), was only 59% effective in healthy adults.
A newer kind of nasal spray vaccine containing a weakened “live” virus, LAIV (live attenuated influenza vaccine) was shown to prevent influenza in 83% of children aged seven or younger.
However, this type of vaccine is not currently recommended for children in the UK.
Dr Michael Osterholm, from the University of Minnesota in the US, one of the lead authors of the study published today in the journal The Lancet Infectious Diseases, said: “Evidence for consistent high-level protection is elusive for the present generation of vaccines, especially in individuals at risk of medical complications or those aged 65 years or older.
“The ongoing health burden caused by seasonal influenza and the potential global effect of a severe pandemic suggests an urgent need for a new generation of more highly effective and cross-protective vaccines that can be manufactured rapidly.
“In the meantime, we should maintain public support for present vaccines that are the best intervention available for seasonal influenza.”
The research showed that pandemic swine flu vaccine was around 69% effective in people aged under 65.
The scientists wrote: “This amount of protection is not adequate for a pandemic setting. The difference between 69% effectiveness and 90% effectiveness (or greater) will have a major public health effect in any pandemic that causes serious morbidity (illness) or increased mortality.”