Few stocks have performed better than Vaxart (NASDAQ:VXRT) of late. Year to date, shares of this company are up by more than 3,400%. And despite these massive gains, Vaxart's market cap is still just $1.34 billion, a reasonable level for a clinical-stage biotech.

Vaxart's efforts to develop an oral vaccine for the novel coronavirus have been instrumental to its performance in the market this year. However, investors will want to pay attention to another opportunity the company is facing, as well.

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Vaxart's potential norovirus vaccine

Vaxart is currently developing a vaccine for the norovirus, a highly contagious virus that causes symptoms such as vomiting and diarrhea. Vaxart's experimental vaccine has already shown promise. In a phase 1 clinical trial, this candidate was well tolerated and triggered broad immune responses. While the development of this vaccine is still in early stages -- Vaxart has only completed two phase 1 clinical studies for it -- the company has high hopes.

According to Vaxart, outbreaks of the norovirus cause 19 million to 21 million cases a year of acute gastroenteritis, an infection characterized by vomiting, abdominal cramps, and nausea, among other symptoms. These cases of acute gastroenteritis caused by the virus lead to 56,000 to 71,000 hospitalizations and 570 to 800 deaths every year. Last week, Vaxart released data from a study that estimated the financial cost of the norovirus in the U.S. 

Woman with hand-drawn question marks floating above her head.

Image source: Getty Images.

According to the study, published in the Journal of Infectious Diseases, the norovirus costs Americans $10.6 billion every year. The data also shows that the bulk of these costs, roughly 50% to be exact, are incurred during the winter. Despite all these factors, there is currently no vaccine for the norovirus approved by the U.S. Food and Drug Administration (FDA). Vaxart estimates that the market for a vaccine for this virus could be as much as $3 billion.

With that said, though, it's important to note that Vaxart isn't the only company currently developing a norovirus vaccine: Japan-based Takeda Pharmaceuticals is also working on a candidate. Still, given that there's a dire need for a vaccine of this kind, there's enough space in the U.S. and abroad for both companies in this market. 

Vaxart's COVID-19 program

Vaxart developed at least five experimental vaccines for the SARS-CoV-2 virus, the novel coronavirus that causes COVID-19, earlier this year. The company ran preclinical trials for these candidates, all of which generated immune responses in "all tested animal models after a single dose." Vaxart selected one of these vaccines as its leading candidate based on the fact that the chosen vaccine had the best chance to trigger "the broadest immune response in humans."

The company plans to start a phase 1 clinical trial for this product as early as this summer. Note that the U.S. government selected Vaxart to join Operation Warp Speed, an initiative that seeks to speed up the development of vaccines and therapies for COVID-19. Vaxart will participate in a non-human primate (NHP) challenge study designed to assess the efficacy of several vaccine candidates. The company could also receive support and funds from the government as part of this operation.

Is Vaxart's stock worth buying?

Vaxart's norovirus program seems promising, but it will be at least half a decade or so before the company can hope to launch this product on the market. In the meantime, it could fail to prove effective in clinical trials. Meanwhile, the race to develop a vaccine for COVID-19 is crowded. Moderna is currently launching a phase 3 clinical trial for its investigational vaccine, mRNA-1273.

Elsewhere, Pfizer and BioNtech will soon start a phase 2b/3 study for their most promising candidate. These two companies have signed deals with the U.S. government and the U.K. government to supply millions of doses of their vaccine, pending regulatory approval. Naturally, investors will want to pay attention to the results from clinical trials for Vaxart's competitors.

It is still too early to know who will win this race, but Vaxart, which has yet to start clinical trials for its vaccine, doesn't seem more likely to cross the finish line than many of its peers. For those reasons, Vaxart's stock seems a bit risky at the moment. For investors willing to take the risk, though, this biotech stock could turn out to be an excellent pick, if everything goes according to plan for the company.