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# Novavax Covid Vaccine Showed Myocarditis Safety Signal: FDA
- URL: https://www.fdaweb.com/novavax-covid-vaccine-showed-myocarditis-safety-signal-fda/
- Published: 2022-06-03T12:00:00.000Z
- Updated: 2026-09-14T17:47:23.000Z
- Author: David McFarland
- Tags: Biologics, #legacy-id-D5151967

An FDA advisory committee briefing document says that Novavax’s Covid-19 vaccine’s two-dose primary series demonstrated significant efficacy, but it also showed similar risk signals seen with other Covid vaccines, such as myocarditis/pericarditis. The agency’s Vaccines and Related Biological Products Advisory Committee is being convened 6/7 to discuss and provide recommendations on whether the benefits of Novavax’s vaccine outweigh its risks for use in individuals 18 years of age and older.

According to the [briefing document](https://www.fda.gov/media/158912/download?ref=fdaweb.com), vaccine efficacy against confirmed mild, moderate or severe Covid-19 was 90.4%. “All Covid-19 cases in the \[Novavax\] arm were mild; in the placebo arm, 11% of cases were moderate and 5% were severe. FDA notes that when data were collected in 2021 the predominant circulating Covid-19 strain was the B.1.1.7 (Alpha) variant.

On the safety side, FDA said: “Multiple events of myocarditis/pericarditis were reported in temporal relationship to NVX-CoV2373 administration, similar to myocarditis following mRNA Covid-19 vaccines and raising concern for a causal relationship to NVX-CoV2373\. Events of lymphadenopathy were infrequent but reported by a higher proportion of participants in the NVX arm, with the highest rate observed after Dose 2 (0.2%). Review of the data also identified small imbalances in certain thromboembolic events, including cardiac and neurovascular events, hypersensitivity events, cholecystitis, uveitis, cardiac failure, and cardiomyopathy. However, a causal association between vaccination and these events cannot be concluded based on available data.”