What happened
Just after the market opened on Monday, Novavax (NVAX 7.85%) shares were hit by an investor sell-off. This was an immediate, sharply negative reaction to a set of Food and Drug Administration (FDA) briefing documents concerning the company's NVX-CoV2373 coronavirus vaccine.
However, probably realizing that this reaction was panic-driven and perhaps unjustified, Novavax's shares staged an impressive recovery. They ultimately notched a gain on the day, closing more than 6% higher and trouncing the S&P 500 index.
So what
The source of investor concern was the FDA's citing of four cases of myocarditis, a heart inflammation, recorded among the patients of a phase 3 clinical trial of the vaccine. The regulator wrote in its briefing, "These events raise the concern for a causal association with this vaccine, similar to the association documented with mRNA COVID-19 vaccines."
Image source: Getty Images.
Any instance of a potentially fatal illness arising from vaccine administration is, of course, serious cause for concern.
But it's worth zooming out to look at the bigger picture. Nearly 30,000 individuals participated in the late-stage trial conducted by the vaccine specialist, which, by the way, demonstrated that NVX-CoV2373 had an efficacy of over 90%.
The FDA wrote that based on this performance that "it is more likely than not that the vaccine will provide some meaningful level of protection against COVID-19 due to Omicron, in particular against more severe disease."
Now what
Novavax also did an admirable job in quickly reassuring the world that our current understanding of myocarditis as it relates to coronavirus vaccines is a "correlation does not imply causation" situation.
"Throughout the pandemic, as publicly available vaccines have been administered, there have been numerous investigations into findings related to myocarditis," the company wrote in a press release published Monday. "We have learned that we can expect to see natural background events of myocarditis in any sufficiently large database, and that young males are at higher risk. Myocarditis is most often caused by nonspecific viral infections."
Novavax added that it will continue to "monitor all adverse events."
