New research out of Oregon Health and Science University provides indirect evidence that humans may develop some immunity to COVID-19.
The question – can people who’ve had the disease be re-infected? — is still one of the big unknowns about the disease.
The study, published in the journal Science, used rhesus macaques as a stand-in for humans and found the COVID-infected monkeys developed antibodies to the virus. Then a month later, all of the macaques were re-exposed.
The results were encouraging: the monkeys didn’t get sick.
“This study I think really provides hope that individual becomes infected with the COVID-19 virus and recovers, it is likely that they will not get COVID-19 again,” said OHSU’s Jake Estes, an author on the study.
Some of the monkeys did show evidence of the virus briefly on re-infection, but their bodies cleared it quickly. And levels of virus were so low, Estes says they would likely not have been infectious to others.
Rhesus macaques are used for this kind of testing because their physiology and immune systems are very similar to humans.
But Estes says more research is necessary to determine if humans will have the same immune response.
“While these monkeys are a very good approximation of humans, they’re not humans,” he said. “There could be significant genetic contributing factors in the human population. There are certainly many more variables in the human population – comorbidities – that are known to be associated with more severe disease.”
In addition, the OHSU work only tested the macaques for immunity about a month out from the initial recovery from the virus. It’s still unknown how long that immunity would last.
The question of immunity is important because indicates if people who’ve had COVID can return to normal life without risk of re-infection. It also gives us a clue whether the immune system can be effectively harnessed to develop vaccines and treatments for the disease.
Another paper out this month comes to a similar conclusion. It shows that people who have recovered from COVID-19 do develop antibodies and other disease fighting mechanisms that could signal immunity.
Still, knowing generally if people develop immunity once they’ve been infected with novel coronavirus and knowing whether an individual has immunity are two vastly different things. Because so many coronavirus infections are asymptomatic, it can be difficult to know if a person has been exposed without reliable antibody testing.