Safety and Immunogenicity of the Novavax COVID-19 Vaccine in Adolescents

More than 20% of COVID-19 infections and 0.4% of related fatalities occur in children. As COVID-19 gradually becomes endemic, it’s more important than ever to ensure all eligible persons are vaccinated to protect themselves and others.

NVX-CoV2373, the recombinant spike (S) protein-based COVID-19 vaccine from Novavax, was recently approved under emergency use authorization for adolescents 12-17 years of age. Previously available only to adults 18 years and older, NVX-CoV2373 offers an alternative to the authorized messenger RNA (mRNA) COVID-19 vaccines.

The results of a randomized clinical trial of NVX-CoV2373 were recently published in JAMA Network Open. The phase 3 trial sought to determine whether NVX-CoV2373 was safe, immunogenic, and efficacious in preventing COVID-19 in adolescents aged 12-17 years.

The study population included adolescents 12-17 years of age, who were either healthy or with stable chronic medical conditions. A total of 2232 participants were included and randomized 2:1 to receive injections of either NVX-CoV2373 or placebo, administered 21 days apart. Exclusion criteria included a prior laboratory-confirmed COVID-19 infection or known immunosuppression.

The 1487 NVX-CoV2373 recipients and 745 placebo recipients averaged 52.5% male, 74.4% White, and 13.8 years of age. A total of 20 mild COVID-19 cases occurred an average of 64 days after intervention, 14 in placebo recipients and 4 in NVX-CoV2373 vaccine recipients, for a vaccine efficacy of 79.5%.

Notably, vaccine efficacy against the Delta variant, the only COVID-19 strain recognized by genomic sequencing, was 82.0%. Vaccine reactogenicity was mild-to-moderate and brief; reactogenicity occurred with greater frequency after the second dose of NVX-CoV2373. Serious adverse events were determined to be rare, and evenly dispersed between the NVX-CoV2373 and placebo recipients.

The investigators determined that the NVX-CoV2373 COVID-19 vaccine was safe, immunogenic, and efficacious against COVID-19 infection in adolescents 12-17 years of age. These findings are significant, as more than 22% of adolescents have yet to receive an mRNA COVID-19 vaccine.

“A favorable safety profile, convenient storage and transportation requirements, and induction of broad, cross-reactive immune responses with the potential to provide protection against new variants suggest that NVX-CoV2373 offers an important choice for vaccination of younger individuals in the fight against the current COVID-19 pandemic worldwide,” the study authors concluded.