What happened

Shares of Novavax (NASDAQ:NVAX) jumped 44% last month according to S&P Global Market Intelligence. The move followed a 38% drop in May. The wild ride has been driven by news about the anticipated timing for the company's vaccine, NVX-CoV2373. After several disappointments, the company finally caught a break in June.

So what

Novavax has experienced repeated delays in getting the vaccine to market, first with regulatory filings and later with production. That latest hurdle is due to the U.S. banning the export of some raw materials the company needs to manufacture its drug

To date, its contract manufacturer hasn't been able to get enough items like bioreactor bags, filters, and enzymes to meet production targets. However, the stock rocketed higher in early June after the ban on sending those items abroad was lifted.

A patient receiving a COVID vaccine from a clinician.

Image source: Getty Images.

Now what

Management now anticipates filing for emergency use authorization in the third quarter and reaching its target of 150 million doses per month by the end of the year. The momentum didn't last long. Novavax stock has already given back nearly half of its June gains in the first week of July. The culprit appears to be concern over the delta variant.

The strain is both more contagious and leads to more severe cases than previous versions of the SARS-CoV-2 virus. Now that it is the most prevalent strain in this country, investors are nervous about what it could mean for vaccine stocks. That's especially true for Novavax. Although its trial showed impressive protection against variants, it was conducted before the delta strain was common. The concern is likely to linger until data is available to quantify how well NVX-CoV2273 protects against the mutation.

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