Novavax COVID-19 Vaccine Found Safe, Effective, Immunogenic for Adolescents

The SARS-CoV-2 (COVID-19) NVX-CoV2373 vaccine (Novavax, Inc) was found to be safe, immunogenic, and efficacious in preventing COVID-19 in adolescents, according to results from an expansion of the PREVENT-19 study published in JAMA Network Open. The vaccine was 79.5% effective at protecting adolescents against COVID-19, primarily the circulating Delta variant.

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“Optimal control of COVID-19 as it moves into an endemic state requires that vaccination be extended to all ages to minimize disease overall and, especially, to reduce the social and mental health effects on children and adolescents,” the study authors wrote in the article.

There are numerous messenger RNA (mRNA) vaccines that are approved to treat COVID-19 in adolescents and younger children and the SARS-CoV-2 NVX-CoV2373 vaccine has recently been added to the list. It is authorized for emergency use in adults aged 18 years and older and adolescents aged 12 to 17 years based on data supporting safety, immunogenicity, and protective efficacy against symptomatic COVID-19. Investigators conducted the research study to describe the data leading to its approval.

The SARS-CoV-2 NVX-CoV2373 vaccine was originally evaluated for safety, immunogenicity, and efficacy in adults in the PREVENT-19 study. It was found to offer 90.4% protective efficacy against circulating COVID-19. This more recent phase 3, 2:1 randomized clinical trial was an expansion of PREVENT-19.

Between April and September 2021, researchers randomized 2247 racially and ethnically diverse adolescents aged 12 to 17 years to receive the NVX-CoV2373 vaccine (n= 1487) or placebo (n=745). The main objectives of the study include serologic noninferiority of neutralizing antibody response compared to young adults aged 10 to 25 years, protection against laboratory-confirmed COVID-19, and reactogenicity and safety.

The vaccine group experienced a higher serologic response than the placebo group, which was also observed in young adults. In addition, the vaccine was 82% effective against the Delta variant alone. Reactogenicity was mild/moderate and more frequent and severe after vaccine number 2, and investigators did not observe new safety concerns during the follow-up. Further, there was rare incidence of severe adverse events.

The data also suggest that the NVX-CoV2373 vaccine may offer broad protective immunity against multiple variants because the study established it as effective against earlier variants from past clinical trials and against the Delta variant in this expansion.

Limitations of the study include a short evaluation time period, limited placebo-controlled follow-up, evaluation of efficacy during circulation of the Delta variant, a low number of cases during the blinded crossover, and excluding participants from the per-protocol efficacy population who were seropositive at baseline.

“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 wrote in the article.

Reference

Áñez G, Dunkle L, Gay C, et al. Safety, Immunogenicity, and Efficacy of the NVX-CoV2373 COVID-19 Vaccine in Adolescents. JAMA Netw Open. 2023. doi:10.1001/jamanetworkopen.2023.9135