Polio Vaccine: Added IM Dose Kicks Up Immunity After Oral Course — Physician’s First Watch
Polio Vaccine: Added IM Dose Kicks Up Immunity After Oral Course
By Joe Elia
Adding an intramuscular dose of inactivated poliovirus boosts immunity in children who've already received the oral vaccine, according to a study conducted in India and published in the Lancet.
Researchers randomized 450 children between ages 1 and 4 who'd received their oral vaccine doses more than 6 months earlier. Half got an injection of inactivated virus vaccine; the other half got none. Then, after 28 days, all children received a challenge with bivalent oral live-virus vaccine.
The primary outcome of interest -- the risk of shedding poliovirus in stool a week after the challenge -- was lower among those who got the injection relative to those who did not (risk ratios, 0.62 and 0.30 for the two virus types in the challenge).
A commentator notes "some incremental individual benefit," but also observes that the cost-effectiveness of the added IM dose at the population level remains "uncertain."