June 2 (UPI) -- Army scientists are testing coronavirus vaccines developed by outside laboratories -- but also one created by the Army itself -- and are optimistic they'll have a vaccine ready by the end of the year.
Using a virus isolated from the blood of a Washington state man who was the virus' first U.S. death, Army researchers are testing vaccines in hundreds of mice, and researchers are also working to evaluate test vaccines produced by pharmaceutical companies under the White House's "Operation Warp Speed," which has a stated goal of producing a virus by the end of the year.
Human clinical trials could begin as soon as the end of the summer.
"We've done a lot of work that you'll hear about in the near future showing that all the [COVID-19-linked] viruses circulating in the world can be covered by a single vaccine," Kayvon Modjarrad, director of emerging infectious diseases at the Walter Reed Army Institute of Research, told reporters Tuesday.
Some reports suggest there are multiple coronavirus strains -- perhaps as many as eight -- circulating around the world, and that some may be more contagious than others, so the possibility of a vaccine that could handle multiple strains would be a significant development.
"There's no evidence currently that there are new strains," Modjarrad said Tuesday, but the Army's vaccine is being designed with a long-term approach to combating new strains of the novel coronavirus, so researchers could more easily fight any strains that arise.
There are still other unknowns researchers have to contend with -- including the possibility of re-infection and the wide variety of health outcomes for the infected.
It's also too early to tell exactly how long the vaccine's effects will last after patients receive it -- since researchers don't yet know how long it lasts from people who get infected naturally.
Ensuring access to the vaccine once it's been developed is also out of the Army's hands.
Instead it will be up to the Centers for Disease Control to execute a campaign to deploy the vaccine broadly, and the the Food and Drug Administration will also have a "very strong hand" in deciding who gets immunized, according to Nelson Michael, the director of the Center for Infectious Disease Research at the Walter Reed Army Institute of Research.