Gaithersburg, MD—Last year, the FDA issued an Emergency Use Authorization for the Novavax COVID-19 Vaccine, Adjuvanted for the prevention of COVID-19 in adults aged 18 years or older.

The FDA discussed the importance of providing another option for vaccination against SARS-CoV-2.

“After a comprehensive analysis and evaluation of the data, and assessment of the manufacturing processes and information, as well as input from the FDA’s committee of external independent advisors, the FDA’s medical and scientific experts have determined that the vaccine meets the FDA’s high standards for safety and effectiveness for emergency use authorization,” Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research, said at the time. “Novavax COVID-19 Vaccine, Adjuvanted provides another alternative for adults and adds another vaccine to the COVID-19 vaccine supply for the United States.”

The Novavax product is an adjuvanted, recombinant spike protein COVID-19 vaccine and provided an option for adults who are hesitant to get an mRNA vaccine, such as those produced by Moderna and Pfizer. Now, a post hoc analysis of the study that led to the Novavax vaccine’s approval has found it highly effective at preventing severe disease and hospitalization. The results of the review by industry researchers were published in the journal Vaccine.

The PREVENT-19 trial was the pivotal phase III trial of the Matrix-M–adjuvanted, recombinant spike protein COVID-19 vaccine (NVX-CoV2373). In circulating SARS-CoV-2 strains at the time of the trial, the vaccine demonstrated an efficacy of 90% for the prevention of mild, moderate, or severe COVID-19.

“Although the vaccine efficacy against moderate-to-severe disease assessed by pre-defined criteria was 100% (95% CI: 87.0, 100), the efficacy in prevention of COVID-19–associated hospitalization was not evaluated,” the authors advised. “Due to the relatively short time span since the authorization of NVX-CoV2373, real-world effectiveness data that may inform its impact on hospitalization are not yet available.”

As a result, the post hoc analysis sought to identify all hospitalizations among the PREVENT-19 efficacy analysis population and to include additional COVID-19–associated hospitalizations that had been excluded from the per-protocol population due to absence of infection confirmation by polymerase chain reaction testing at the central study laboratory. “Further, we sought to detail clinical narratives of all hospitalized patients to better understand the underlying risk factors for COVID-19–associated hospitalization in trial participants,” the study team wrote.

PREVENT-19, which involved participants who received two doses of the vaccine or placebo 21 days apart, demonstrated that the vaccine was well tolerated and efficacious with a vaccine efficacy of 90% for the prevention of symptomatic COVID-19. “Throughout the study, the predominant SARS-CoV-2 variant was alpha, but additional variants were in circulation (i.e., beta, gamma, epsilon, and iota). VE [vaccine effectiveness] among the per-protocol efficacy analysis population was calculated according to pre-specified disease severity (mild, moderate, or severe) criteria, but the impact on the risk of COVID-19-associated hospitalization was not specifically investigated,” the researchers pointed out.

During the analysis period of 95 days, four hospitalizations occurred among the 77 events analyzed for the primary endpoint using the per-protocol population, all of them among placebo recipients. Because no hospitalizations occurred among vaccine recipients, the post hoc vaccine efficiency against hospitalization was 100% (95% CI: 28.8, 100).

“Among an expanded efficacy population, also identified post hoc, which included COVID-19-associated hospitalizations without a requirement for diagnostic polymerase chain reaction testing performed at the study central laboratory, 12 total hospitalizations were identified, zero among vaccine recipients and 12 among placebo recipients, yielding a post hoc VE against hospitalization of 100% (95% CI: 83.1, 100),” the authors added. “These additional data from the PREVENT-19 trial provide relevant public health information concerning the attributes of NVX-CoV2373.”

The Novavax COVID-19 Vaccine, Adjuvanted is administered as a two-dose primary series, 3 weeks apart. The vaccine contains the SARS-CoV-2 spike protein and Matrix-M adjuvant. Adjuvants are incorporated into some vaccines to enhance the immune response of the vaccinated recipient. The spike protein in this vaccine is produced in insect cells; the Matrix M-adjuvant contains saponin extracts from the bark of the Soapbark tree that is native to Chile.

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

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