Flu season is upon us, and in the fall, the Centers for Disease Control and Prevention (CDC) reported that the most common circulating strain of flu in the U.S. is resistant to oseltamivir (marketed as Tamiflu®). Although it appears that there is plenty of flu vaccine to go around, what if there were a shortage? Would a half-dose of the vaccine be enough? Half-dose vaccination may be effective for flu prevention in healthy adults under the age of 50, according to a study published in a recent issue of Archives of Internal Medicine .

Doctors from Walter Reed Army Medical Center in Washington, DC and their colleagues evaluated healthy adults aged 18 to 64 in order to determine the effects of age, sex, and dose on the efficacy of the influenza vaccine. The study participants were randomly assigned to receive either a full- or a half-dose of the flu vaccine. The doctors found that, both dosages elicited a similar immune response among participants in the 18- to 49-year old age range. However, among patients in the 50- to 64-year old age group, a half-dose was as effective as a full-dose for some flu strains, but not others.

Based on the findings of this study, it seems that, in the setting of a flu vaccine shortage, half-dose vaccination might be an effective strategy for healthy adults under the age of 50.

Source

Arch Intern Med. 2008;168(22):2405-2414.