WASHINGTON _ Army scientists have a vaccine candidate that they believe has the potential to fight COVID-19 _ and that may be able to protect individuals from future coronaviruses, "from season to season, for decades to come."
The scientists at the Walter Reed Army Institute of Research chose SpFN, for Spike Ferritin Nanoparticle, after testing dozens of variants of vaccine candidates in more than 1,000 mice.
"It was a real sense of relief" to discover a strong vaccine candidate, Dr. Kayvon Modjarrad, director of Walter Reed's Emerging Infectious Diseases Branch, said in an exclusive interview with McClatchy. "Our team has not taken a day off in three, four months, since this all started. After we got that result I said, 'you know, we can at least take one day off.'"
Their progress comes as cases of COVID-19, the disease caused by the novel coronavirus, topped 2 million in the United States, and as 21 states have seen an increase in positive cases in recent weeks.
SpFN differs from other vaccines under development, in that it uses a soccer ball-shaped protein that allows scientists to harness the spikes of multiple coronavirus strains on 24 different faces of the protein. That attracted a stronger immune system response in tests with mice than other approaches, where there was only one spike of the coronavirus inserted on a vaccine candidate.
"The one that we selected from all those different versions, is one that actually, even after giving one dose, looks much better than if you were to give just the spike protein alone, which is in other vaccines _ if you gave multiple doses of that vaccine _ one dose of our vaccine looks better already," Modjarrad said.
This vaccine also has the potential to fight off future variants of the coronavirus because different versions of the virus can be put on the spikes, he said.
"You can mix-and-match the different spikes you put on that particle, that soccer ball, so you have different coronavirus strains on there," Modjarrad said. "If things look good for our vaccine, we hope that it'll be complementing the vaccines that are already out there as a long-term approach from season to season, for decades to come."
The result may be a vaccine that can offer protection against future strains of the virus, he said.
"We wanted to make sure we were developing a vaccine that would address coronaviruses in the future _ either this coronavirus that would mutate into other strains potentially from season to season, like we see with flu, or other coronaviruses that are out there now that don't cause as severe a disease, or inevitably what we anticipate to be more coronaviruses that come in the future," Modjarrad said. "We can use this platform as a universal approach to address all those coronaviruses."
The vaccine, like many others under development, is being fast-tracked. Now that it has been vetted for generating an immune system response, it will move into further testing, involving monkeys, to see if the vaccine protects them against the virus.
At the same time, it will move into a manufacturing phase, where samples of the vaccine will be further reviewed to meet government safety standards, to have supplies of the vaccine on hand and ready to go for initial human trials in the summer.
If those limited trials work, the vaccine will go into more widespread human trials in the fall and early winter, Modjarrad said.
It will take additional research _ tracking people who receive the vaccine candidate _ to know how long immunity will last, and whether individuals would need to receive this vaccine on a recurring basis, like a flu shot, or whether it could be a one-time shot, he said.
Four major private-sector companies _ Moderna, AstraZeneca, Johnson and Johnson and Sanofi _ are also currently in human trials with vaccine candidates of their own.
Those candidates are the focus of Operation Warp Speed, an all-of-government push for the discovery and development of a coronavirus vaccine by the end of this year.
While President Donald Trump has pushed an aggressive timetable for vaccine development, immunologists and virologists outside of government have questioned the likelihood of achieving a vaccine that is proven to be effective, long-lasting, safe and widely accessible before 2021.
"What's happening in the 'Warp Speed' program is that the products that can be made the most quickly in the greatest amount have gotten the most attention. And these protein-based vaccines are harder to make in bulk. That's the wider-angle dynamic," said Dr. John Moore, a professor of microbiology and immunology at Weill Cornell Medical College.
Moore, a grantee of the National Institute of Allergy and Infectious Diseases at the National Institutes of Health, said widespread concerns remain that the pressure to succeed on an unprecedented timeline could lead vaccine producers _ including Army researchers _ to shorten what is typically a lengthier process to thoroughly investigate safety issues.
"I have seen nothing published on this particular vaccine concept, and it's unlike the ones that have received high-profile publicity to date _ it's a different design. This kind of immunogene science is likely to induce a stronger antibody response than the nucleic acid," he said. "But proving efficacy and safety is a laborious process _ you can't cut corners."
