WASHINGTON _ Army labs conducting research on the coronavirus are confident that "some form" of a vaccine will be identified by the end of this year, but cautioned that large-scale access to it will take time and that much remains unknown about COVID-19.
The Army scientists are working on a vaccine candidate that is separate from four major private-sector efforts that are currently in human trials and 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.
But while the government's goal is to achieve a vaccine "in some scale" by the end of 2020, ramping up public access will almost certainly extend into 2021, one Army scientist said on a call with reporters Tuesday.
"It is reasonable to expect that there will be some form of a vaccine that could be available at some level to a certain population by the end of the year, the first of the year," said Col. Wendy Sammons-Jackson, director of the Military Infectious Disease Research Program at the U.S. Army Medical Research and Development Command at Fort Detrick, Md.
Dr. Kayvon Modjarrad, director of emerging infectious diseases at Walter Reed Army Institute of Research, said the next step in their lab's COVID-19 vaccine development is just days away.
"We have been vaccinating hundreds and hundreds of mice with different versions of our vaccine, and we will be making a decision as to which one is the best one that we will be taking forward for manufacturing next week," Modjarrad said.
President Donald Trump has pushed for an aggressive timeline for vaccine development. "Vaccines are coming along really well. Likewise therapeutics," Trump wrote in a tweet Tuesday. "Moving faster than anticipated. Good news ahead (in many ways)!"
While Army researchers expressed confidence that the Trump administration's goal is realistic, they highlighted several unknowns in their continued research into COVID-19, the disease caused by the novel coronavirus that has killed more than 105,000 people in the United States.
"Every time we think we have it cornered and we know exactly what the clinical signs of the disease are, how it replicates, how it moves through populations, it does something different and we learn something new," said Dr. John Dye, chief of viral immunology at the U.S. Army Medical Research Institute of Infectious Disease.
Scientists do not know whether antibodies provide any level of protective immunity to those who have recovered from the coronavirus when they are reexposed _ and cannot say whether any of the vaccine candidates, including the one under development by the Army, will provide durable, long-term protection.
Of the four private firms also working on vaccines _ Moderna, AstraZeneca, Johnson and Johnson and Sanofi _ the scientists said it is likely Moderna's version will become the first to be tested in a large-scale Phase III clinical trial.
But the Army labs are also thinking beyond this year's outbreak and looking for a vaccine that might take on future coronavirus variants.
"Our particular vaccine takes a long-term approach towards a potential new strain of COVID-19, and other coronaviruses in the future," Modjarrad said. "There is no evidence currently that there are new strains. We actually have done a lot of work that you'll hear about in the near future showing that all the viruses currently circulating in the world can be covered by a single vaccine."
Other vaccine candidates are being built to deliver a single, neutralizing spike protein to combat the novel coronavirus, Modjarrad said. He described the Army vaccine protein under development as another model, looking like a soccer ball with 24 distinct facets, allowing them to "mix and match" different spike proteins that can address various strains of coronavirus in a single vaccine.
"In the event that the virus can mutate, our vaccine is positioned to be able to cover any new strains or species of the virus," Modjarrad added.
While Modjarrad said that the coronavirus has yet to mutate, researchers at Los Alamos National Laboratory recently published a study showing that various strains of the virus had reached the United States at different times, and were demonstrating varying degrees of contagiousness.
Concerns over the coronavirus's potential to mutate, and a lack of knowledge about an individual's natural immunity to the virus after recovery, have complicated the scientific push for a vaccine.
"We're learning about the science of this new virus faster than we have about any other virus before," Modjarrad said. "So going to a vaccine in a matter of months, from concept all the way to stage three clinical trials and potentially licensure, is unprecedented _ but in this case I think very much is possible."
