IMMUNE-RESPONSE TO INFLUENZA VACCINATION OF ELDERLY PEOPLE - A RANDOMIZED DOUBLE-BLIND PLACEBO-CONTROLLED TRIAL

The objective of this study was to determine the immune response to in fluenza vaccination in elderly people, using a randomized, double-blin d, placebo-controlled trial. Venous blood was taken from 1838 people a ged 60 years and older, prior to injection with the influenza vaccine or a placebo. A second blood sample was taken three weeks later. The a ntibody reaction was measured bq, comparing the geometric mean titre a nd the percentage of participants who had a protective antibody titre before and after vaccination and for all sera of each strain. A protec tive antibody titre was found in 43-68% of those who had received the vaccine, depending on the strain investigated. Patients potentially at risk showed a response similar to the other participants. We conclude that influenza vaccination in elderly people provides a reasonable to good immune response. Research is needed on whether a good immune res ponse decreases the incidence of influenza.