What happened

There's nothing like a surge in a deadly disease to encourage investors back into a noted healthcare stock. This dynamic benefited biotech Novavax (NVAX 3.54%) on Thursday.

It was also on the back of one pundit's recommendation upgrade; together these factors sent the company's share price 8% skyward. That performance trounced that of the S&P 500 index, which essentially traded sideways.

So what

The latest COVID subvariant, Eris, is beginning to get significant coverage in the media. For instance, on the website of the TV news magazine Today, Eris was described as "sweeping" through this country.

Echoing other media coverage, Today pointed out that Eris has become the dominant COVID subvariant on our shores. It added that, according to the latest two-week period, it comprised more than 17% of newly confirmed COVID cases. That was notably higher than the 12% of the preceding two-week frame. 

At the moment, Novavax's Nuvaxovid is one of only three COVID vaccines authorized for use by the U.S. Food and Drug Administration.

Now what

The upgrade, enacted by B. Riley analyst Mayank Mamtani, pushed Novavax into the buy category, at a price target of $15 per share. Previously, Mamtani had ranked the biotech as only a neutral. 

It wasn't immediately apparent why the prognosticator made his move, but it hardly qualifies as a surprise. On Tuesday, the company posted second-quarter results featuring revenue that was far higher than the consensus analyst estimate, and a bottom line that unexpectedly -- and dramatically -- flipped into profitability.