Pfizer’s three-dose vaccine elicits strong reaction in youngest children

MONDAY, May 23, 2022 (HealthDay News) — Pfizer/BioNTech says a three-dose regimen of its COVID-19 vaccine appears to elicit a strong immune response in the youngest children, those 6 months to 5 years old.

This is the only age group not yet approved for vaccination against COVID-19 by the United States Food and Drug Administration. Pfizer said it plans to submit its new data to the agency this week.

The Phase 2/3 trial involved nearly 1,700 children who received a child-sized third dose of the vaccine at a time when the omicron variant was dominant. Tests carried out a month later showed an antibody response similar to that seen in 16- to 25-year-olds who received two doses of the vaccine.

Midway through the trial, the third dose gave young children 80% protection against asymptomatic COVID-19. The researchers identified 10 symptomatic cases of COVID-19 occurring at least seven days after the third dose. But the Pfizer team stressed that their analysis cannot be completed until at least 21 symptomatic cases occur in the vaccinated group and are then compared to the number of symptomatic cases in the unvaccinated group.

Vaccine doses have been adjusted downward for these smaller children – three 3mcg doses for those aged 6 months to 5 years. This is compared to two doses of 10 mcg for children ages 5 to 12 and two doses of 30 mcg for people 12 and older. Children in the youngest age group receive the first two doses three weeks apart and a third dose two months later. There do not appear to be any safety issues with the vaccine, which was well tolerated by children.

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