What happened

Shares of Novavax (NVAX -3.74%) were bouncing back on Tuesday, rising 7.1% as of 12:50 p.m. ET after jumping as much as 14.7% earlier in the day. The gain came after an analyst's downgrade caused the stock to plunge last week.

Novavax had good news to report on Tuesday, though. The company announced that it's made 1 million doses of COVID-19 vaccine Nuvaxovid available for use in the U.K.

So what

It's difficult to predict how much uptake Nuvaxovid will enjoy in the U.K. Novavax received Conditional Marketing Authorization (CMA) from the country's Medicines and Healthcare products Regulatory Agency (MHRA) in February 2022 for vaccination of adults ages 18 and older. The company picked up another authorization for adolescents ages 12 through 17 last month.

But more than 80% of adults in the U.K. have already received at least one dose of a COVID-19 vaccine. Around 75.5% of adults in the country are fully vaccinated. Perhaps some of the unvaccinated who didn't want messenger RNA vaccines could be interested in Novavax's protein-based vaccine, especially if there's a major surge in COVID-19 cases as winter approaches.

However, Nuvaxovid still isn't available in the U.K. as a booster. Novavax filed for expanded CMA of its vaccine as a booster in adults in June but is still awaiting a decision from MHRA.

Now what

Novavax really needs to secure authorizations in the U.K. and the U.S. for Nuvaxovid boosters. In the meantime, it's likely that the vaccine stock will remain highly volatile. 

Over the longer term, though, Novavax could have an opportunity to achieve greater success. The company should soon announce results from a late-stage study of its vaccine targeting the coronavirus omicron variant. It also plans to advance a combination COVID/flu vaccine candidate into late-stage testing in 2023.