While much of the discussion around COVID-19 vaccines has lately focused on the difficulties of shipping and storing them at temperatures that would make a polar bear shiver, Vaxart (NASDAQ:VXRT) has been steadily working on developing one that would eliminate a lot of the logistical complexity. The company's coronavirus vaccine candidate comes in tablet form, and is shelf-stable at room temperature.

Investors rewarded the effort by driving Vaxart's shares up by more than 1,500% last year, from $0.35 to $5.71. With gains like that in the rear-view mirror, could there still be upside for investors who buy shares today?

An elderly man wearing glasses and a flannel shirt reclining in a chair, holding a glass of water and a pill that he is about to ingest.

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A huge opportunity in oral vaccines

In June, Vaxart's COVID-19 candidate was tapped to be among those evaluated in a non-human primate study funded by Operation Warp Speed. It originally showed promise in animal studies; management expects that its phase 1 human clinical trials will be completed in the first quarter, and expects to launch phase 2 trials this quarter as well.

This isn't the company's first collaboration with the government on a vaccine. In mid-2019, Vaxart partnered with Johnson & Johnson's (NYSE:JNJ) Janssen unit to develop a flu vaccine in tablet form. That research was funded by the Biomedical Advanced Research and Development Authority (BARDA). The partners reported phase 2 study results in January 2020 that showed their oral vaccine at least matched the performance of Sanofi's influenza vaccine -- the market leader.

If Vaxart is successful, the potential for its valuation to soar is still enormous. The company only has a market cap of $715 million and is also working on vaccines for norovirus, human papillomavirus (HPV), and respiratory syncytial virus (RSV).

Even if one ignores the potential revenues for a norovirus vaccine (hard to gauge, because there are no currently licensed vaccines for it) and COVID-19 (because there are 50 candidates ahead of it in the clinical trial process), vaccines for those other conditions are expected to generate global annual sales of $21 billion by 2027. If Vaxart can win a share of that market, it will give shareholders plenty of reasons to stay excited about the stock in 2021 and beyond.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.