A new government policy has been developed to avoid many serious cases of influenza. This goal will be accomplished by the annual vaccination of high-risk individuals: everyone 65 and older as well as anyone with a chronic disease that might cause them to experience complications from the influenza virus. Each year' s vaccination will protect only against the strain of the influenza virus deemed most likely to be prevalent that year
every year it will be necessary for all high-risk individuals to receive a vaccine for a different strain of the virus.
Each year the strain of influenza virus deemed most likely to be prevalent will be one that had not previously been deemed most likely to be prevalent.