Moderna and Pfizer were first to market with their coronavirus vaccines. The U.S. Food and Drug Administration (FDA) granted them both Emergency Use Authorization (EUA) last month. But that doesn't mean the vaccine race is over. Considering global demand, there is plenty of room for other players.

Still, once the crisis has eased and vaccination becomes routine rather than urgent, certain players may emerge as market leaders. The type of vaccine that can stand out in the crowd would be one offering ease of use and few distribution challenges. Today, Vaxart (NASDAQ:VXRT) and Altimmune (NASDAQ:ALT) are working on exactly those kinds of products. Let's take a closer look at these under-the-radar coronavirus vaccine stocks.

Hand holding bag labeled COVID-19 Vaccine beside sign saying 2021 Goals

Image source: Getty Images.

Vaxart

Vaxart's investigational product is an oral COVID-19 vaccine. It's in tablet form -- ideal for those of us who avoid shots at all costs. The clinical-stage biotech company launched a phase 1 study of the vaccine candidate in October 2020 and completed enrollment a month later. Earlier, the vaccine candidate showed promising preclinical results. In a study, all vaccinated hamsters maintained or gained weight after exposure to the virus -- a sign of protection against infection in this type of animal.

Vaxart's investigational vaccine offers ease of use to the person receiving it. But it also makes life easier for those transporting, storing, and administering the product. The tablet is room temperature stable, so it doesn't require refrigerators or freezers. That element has been a challenge with the Pfizer vaccine. That product requires ultra-low temperatures, making it difficult for small pharmacies and medical offices to store.

Now, all eyes will be on Vaxart's phase 1 data. And this could be a make it or break it moment. When Vaxart announced the start of its trial, it expected to receive the first data "in the next few weeks." So, it seems likely we may expect an interim report soon.

Vaxart's shares are down 63% from their peak in July as investors turned their attention to companies further along in the race, such as Moderna or Novavax. But any positive trial data ahead could offer a huge lift.

Altimmune

Let's start out with the bad news first. Last month, the FDA placed a clinical hold on Altimmune's application for a phase 1 trial of its coronavirus vaccine candidate. The regulatory agency asked for certain changes to study protocol and asked to see more chemistry, manufacturing, and controls data. Now here's the good news. Altimmune has replied to the FDA, agreed to requests, and doesn't expect the hold to slow the development program.

Of course, the hold is an additional element of risk. But Altimmune's statement is reason to be more optimistic than pessimistic at this point.

So why could Altimmune's vaccine candidate be an eventual winner? AdCOVID is given in a single dose, intranasally. Both of these elements are key. The coronavirus vaccines authorized so far are given in two doses. One dose simplifies the process. It also means a specific number of doses can be used in more people.

An intranasal vaccine -- or nasal spray -- offers a significant advantage. The nose represents the point of infection and viral replication. So, an intranasal vaccine could target the virus locally and even prevent its spread. And finally, this potential product can be stored at room temperature for months. Like Vaxart's investigational vaccine, this one also would be easier to store and transport than the currently authorized vaccines.

Like Vaxart, Altimmune's shares have dropped from their July peak -- by 62%. If Wall Street's average share price forecast is right, Altimmune's shares could more than triple from today's price in 12 months.

A word on risk

As exciting as Vaxart's and Altimmune's programs sound, there is one important point to keep in mind before investing. Both stocks are highly risky and best left to aggressive investors. A failure in human studies would be devastating for the shares. But if Vaxart and Altimmune report positive human data in the months to come, the shares may soar. And the sky would be the limit for the stock prices if the FDA eventually approved these innovative vaccine candidates.