Can you develop immunity to coronavirus?
April 1, 2020
OKLAHOMA CITY, March 30, 2020 —As the number of cases of the new coronavirus continue to grow, people who recover are increasingly asking one question: Am I now immune to future infection?
The answer, say experts at the Oklahoma Medical Research Foundation, is not yet clear. But based on preliminary information about the virus, they are hopeful.
When you’re exposed to a virus or bacteria, your body tries to rid itself of the invader by creating proteins known as antibodies. These antibodies seek and attempt to destroy the trespassers, and the body keeps some antibodies on hand ready to fight if you’re exposed again.
“We already know that people make antibodies to the new coronavirus,” said Oklahoma Medical Research Foundation immunologist Linda Thompson, Ph.D. “However, we don't yet know if these antibodies are protective, especially long-term.”
A study in macaques infected with SARS-Cov-2, as the new virus is technically known, suggested that once infected, the monkeys produce neutralizing antibodies that help them resist further infection. But it is unclear how long they might remain immune.
“For example, immunity to SARS, another closely related coronavirus, does protect patients from a second infection for a couple of years,” said OMRF physician-scientist Hal Scofield, M.D. “But, after that, they can be infected again.”
That’s because some viruses evolve over time, allowing them eventually to dodge the immune system, Scofield said.
“Luckily, for typical virus infections, people who recover usually have some protective immunity against repeat infection, at least for a short period of time,” said Thompson.
Still, even if antibody protection were temporary and people eventually became reinfected, the next bout would likely be milder than the first. Even after the body stops producing antibodies, immune memory cells can trigger an effective defense.
“Chances are, you’d make a strong immune response before you even become symptomatic again,” said Scofield. Even in at-risk individuals, the disease might no longer be life-threatening.
Commercial kits for testing for SARS-Cov-2 antibodies have been used in Asian countries, and the tests have recently become available in the U.S. They will enable testing to determine people who have been exposed to—and recovered from—the virus.
“So, at least in the short run, antibody-positive doctors and nurses could likely attend to COVID-19 patients without risk of reinfection,” said Scofield, who also serves as associate chief of staff for research at the Oklahoma City VA.
Using the antibody tests, scientists at OMRF will initiate studies to determine what antibodies the immune system produces to the coronavirus. They’ll also look at what protections, if any, the antibodies offer, and they’ll use this information to help inform the development of new treatments and a vaccine against SARS-Cov-2.
For example, identifying recovered people with powerful antibody responses could allow doctors to inject antibodies extracted from their blood into those who are ill. This method has been used successfully in the past, as long ago as the Korean War.
More recently, it’s also served as an important stopgap during outbreaks of contagious disease. “Before vaccines were developed, this approach was used to treat people infected with Ebola,” said Thompson.