THURSDAY, Aug. 12, 2021 (HealthDay News) — The results of an interim analysis suggest that two doses of the Moderna mRNA-1273 vaccine safely induce protective levels of antibodies to SARS-CoV-2 among adolescents, according to a study published online Aug. 11 in the New England Journal of Medicine.

Kashif Ali, M.D., from Kool Kids Pediatrics in Houston, and colleagues randomly assigned 3,732 healthy adolescents aged 12 to 17 years in a 2:1 ratio to receive two injections of the mRNA-1273 vaccine or placebo (2,489 and 1,243, respectively) 28 days apart, as part of an ongoing phase 2/3 trial.

The researchers found that the most common solicited adverse reactions after the first and second injections were injection-site pain (93.1 and 92.4 percent, respectively), headache (44.6 and 70.2 percent, respectively), and fatigue (47.9 and 67.8 percent, respectively) in the mRNA-1273 group and injection-site pain (34.8 and 30.3 percent, respectively) headache (38.5 and 30.2 percent, respectively), and fatigue (36.6 and 28.9 percent, respectively) in the placebo group. There were no serious adverse events related to the mRNA-1273 vaccine or placebo reported. Relative to young adults (age 18 to 25 years), the geometric mean titer ratio of pseudovirus neutralizing antibody titers in adolescents was 1.08 (95 percent confidence interval, 0.94 to 1.24) and the absolute difference in serologic response was 0.2 percentage points (95 percent confidence interval, −1.8 to 2.4), meeting noninferiority criterion. In the mRNA-1273 vaccine group, there were no reported cases of COVID-19 within 14 days after the second injection compared with four cases in the placebo group.

“In this interim analysis of the ongoing trial, the overall benefit-risk profile of mRNA-1273 was favorable in adolescents,” the authors write.

Several authors are employees of Moderna, which funded the study.

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