Three child-size doses of the Pfizer/BioNTech Covid-19 vaccine appeared to be safe and showed a strong immune response in children ages 6 months to 5 years, the companies said Monday. The vaccine makers said they will finish submitting the trial data to the US Food and Drug Administration this week.
The Phase 2/3 trial included 1,678 children who received a third dose during the period when the Omicron coronavirus variant dominated. Antibody levels tested one month after the third dose showed the vaccine produced a similar immune response as two doses in 16-to-25 year-olds, the companies said in a news release. The data has not yet been peer-reviewed or published.
Midtrial results found vaccine efficacy of 80.3% against symptomatic Covid-19 in this youngest age group. The companies identified 10 symptomatic cases at least seven days after the third dose. However, the efficacy rate won’t be finalized until at least 21 symptomatic cases are found in the vaccine group and then compared with the number of symptomatic cases in the placebo group.