Researchers around the world are working at a feverish pace to develop a vaccine for the novel coronavirus, as the number of cases worldwide surpasses three million.
The labs are found in universities, government agencies and pharmaceutical companies. But in Silver Spring, Maryland, one such lab actually belongs to the U.S. Army, and it's been at the forefront of infectious disease research for more than 100 years.
ABC News was invited inside the lab at the Walter Reed Army Institute of Research (WRAIR), which is now open 24 hours a day, seven days a week in pursuit of a coronavirus vaccine.
The lab's vaccine candidates are already in animal testing and WRAIR hopes to begin human clinical trials in late summer.
"Amazingly, in that growing landscape of vaccines, our approach is unique," said Dr. Kayvon Modjarrad, the director for emerging infectious diseases at WRAIR. "It presents that part of the virus -- the spike protein that's the hook that gets attached to your lung cells -- a lot of vaccines just present one of those to the immune system. Our approach presents them multiple times."
The immune system will then respond by creating antibodies to the presented spike protein.
Modjarrad is leading the Army's effort to develop a coronavirus vaccine. The advantage to their approach, he said, is that the vaccine could be used for all coronaviruses, not just COVID-19, because other viruses in the coronavirus family have similar protein spikes on their surface.
"Now is actually the time to think about the next coronavirus as well. … We need to be thinking decades, generations in terms of our approach to these vaccines and these viruses," he told ABC News on Tuesday.
But even with an eye toward the long term, the lab is keenly attuned to the urgency for a vaccine -- pursuing a staggering pace of development. Modjarrad led the Army's efforts to develop a vaccine for the Zika virus -- a timeline he called "unprecedented" at the time, bringing a vaccine to clinical trials in just nine months.
"We're actually trying to beat that process, that timeline now," he said.
And there are challenges that make a coronavirus vaccine even more difficult to develop than a Zika vaccine.
"Zika was part of a family of viruses that we have vaccines for," Modjarrad said. "The world does not have any coronavirus vaccine license. It's not just a vaccine for COVID-19 that doesn't exist, it's a vaccine for any coronavirus that doesn't exist."
Vaccine development is one of several efforts underway at WRAIR related to the coronavirus, including therapeutics and rapid diagnostic tests.
The lab is also looking at how monoclonal antibodies could be used to help individuals fight off the virus once infected or prevent them from getting sick in the first place. Monoclonal antibodies are laboratory replicated clones of a specifically selected antibody. Instead of injecting a patient with all the antibodies a person developed to fight the virus, scientists isolate the ones deemed most effective at achieving that task and then make vast quantities of them synthetically.
"There are certainly monoclonal antibodies that are showing the right type of behavior in the lab," said Dr. Gordon Joyce, head of structural biology at WRAIR.
"These antibodies look great in the test tube, and that's where the next set of testing is really going to verify whether they can protect against infection," he added. "We have to make sure everything is safe, everything is tested carefully."
Another effort involves partnering with the Massachusetts Institute of Technology (MIT), the Defense Advanced Research Projects Agency (DARPA), and Southwest Research to search for drugs that already exist to see if any compounds could be effective in treating COVID-19. Using artificial intelligence, researchers were able to go through chemical libraries that contain millions of compounds to initially select 80 that could be promising and will now be tested in labs.
Founded in 1893, WRAIR has infectious disease work in its DNA. The institute is named after Walter Reed, an Army major who contributed leading research on the spread of typhoid and yellow fever in the late 1800s. The institute is now physically separated from the well-known Walter Reed National Medical Center in nearby Bethesda, Maryland.
"When we send soldiers around the world, they not only face the threat of the enemy, they face the threat of diseases that we don't have here in the United States," said Col. Deydre Teyhen, commander of WRAIR. "And so our job at the Walter Reed Army Institute of Research is to create ways to prevent that and protect them."
"The coronavirus is one of those diseases that started overseas and it has come to our shores, but it is one of many that we actually create vaccines for or therapeutics or diagnostic tests," she told ABC News.
In fact, WRAIR has been involved with half of all FDA-approved vaccines, she said.
There are currently more than 100 COVID-19 vaccine candidates worldwide, according to the World Health Organization, with seven already in human testing.
Still, Teyhen said she is "hopeful" that WRAIR's vaccine "will be one of those candidates that gets across the finish line." But she, like Modjarrad and Joyce, stressed that safety and effectiveness are the top priority in vaccine development.
"It's healthy competition because we share data," Teyhen said. "We're constantly calling all the other folks that are creating a vaccine, learning from what they're doing. They're helping. We're helping them. Because the reality is the goal is to protect people from this disease."
"A vaccine that is safe is the most important thing," Modjarrad echoed. "Next is a vaccine that works. … We are, as I said, compressing years of work into months, but we are doing it really very carefully. We are not going to accelerate this process at the expense of safety. We're not going to take any shortcuts, and that's good science. Good ethics will drive our whole vaccine development process -- not only here within the Army, but across the entire landscape."
And despite the months of long hours and high stakes, there is optimism.
"I would be very shocked and disappointed if we don't have something," said Joyce. "I am very hopeful, and I think we will get something."