Should people who have recovered from Covid get vaccinated?

Public health officials hope to vaccinate as many people as possible to turn the tide of the coronavirus pandemic once a vaccine becomes available – even those who have already recovered from Covid-19.

And while it is not yet clear how the immune system of Covid-19 survivors responds to a vaccine – especially among coronavirus “long-haul” people, whose symptoms persist for weeks and months after their diagnosis – there is probably little risk in the shot.

“The general recommendation is to get vaccinated, even if you’ve been infected before,” said Dr. David Thomas, professor of medicine and director of the division of infectious diseases at Johns Hopkins University School of Medicine. “There are nuanced questions that we don’t have an answer to yet, but from what we now know, this is the right call to get the vaccine.”

It is believed that re-infections with Covid-19 are rare, but if the levels of natural antibodies decline over time, it is possible that a person will be infected more than once. Doctors and infectious disease experts agree that most people should get the vaccine, even if they have natural protective immunity. In most survivors, a vaccine could even boost immunity against initial infections.

It is a precaution with a precedent. Healthy adults over 50 are still advised to get the shingles vaccine even if they have had chickenpox or shingles in the past.

“I did it because I wanted extra immunity to protect myself against a relapse of shingles later in life,” Thomas said of his recent decision to get the shingles vaccine. “Even though I had been infected before and had some immunity, I still chose to get the vaccine to double that and make myself even safer.

The Food and Drug Administration is reviewing data on two vaccine candidates, developed by Pfizer and Moderna, and an independent advisory committee from the Centers for Disease Control and Prevention voted on Tuesday to approve the recommendations for who should be the first to receive the vaccines. . The recommendations will go to the CDC director for formal approval. The planned deployment has huge implications for how the country is recovering from the pandemic, but it also raises questions about how the nearly 14 million people in the United States who have already had confirmed cases of Covid -19 will be affected.

Vaccine trials set up by Pfizer and Moderna included participants from diverse racial and ethnic backgrounds, but they did not focus on people who previously had Covid-19.

These types of detailed considerations are part of the vaccine approval process, and Thomas said Pfizer and Moderna are expected to provide data on a number of outstanding issues even after the FDA initially granted approval to use it. emergency.

“Usually after something is approved, the FDA will say we give you the approval, but you have to do all of these things within a certain amount of time and answer all of these questions by a certain date or you lose it. approval, ”Thomas said. “Businesses are then required to do all of these things, but in the meantime you are not delaying everything.”

Some of the stipulations are likely to include specific questions about administering vaccines to people who have had Covid-19, along with any associated safety data.

So far, there is no evidence that a vaccine would be dangerous for Covid-19 survivors, but more research is needed, said Dr Sarah Fortune, president of immunology and infectious diseases at Harvard TH Chan School of Public Health.

“There haven’t been any serious adverse events that make me think this would be a major problem, but I think this analysis needs to be done,” she said. “The first question is about safety, but the second question is: is there an added benefit?”

Although the Pfizer and Moderna vaccine trials did not recruit volunteers who were symptomatic or known to have previously been infected, it is believed that up to 10% of trial participants had the virus, said Dr Moncef Slaoui, the chief scientist. advising on Operation Warp Speed, the Trump administration’s $ 18 billion initiative to support coronavirus vaccine development. These people were either asymptomatic or had symptoms so mild that they went undetected, he said.

“What we know is that vaccines are safe in these populations,” Slaoui said Wednesday during a press briefing on Operation Warp Speed. He added that more data was needed on how the vaccine worked in people who had symptoms and had Covid-19.

Another big unknown is the “long haul” response to Covid-19, said Michael Betts, immunologist and professor of microbiology at the Perelman School of Medicine at the University of Pennsylvania.

It is not known how many people suffer from long-term symptoms of Covid-19, but a CDC study released in July found that 35% of adults who were symptomatic but were never sick enough to require hospitalization were not returned to their usual state of health. three weeks after their diagnosis.

Part of the challenge of assessing how these patients might be affected by a vaccine is that it is still unclear why their symptoms persist.

“We really don’t understand why these people are suffering like this, so my concern is that we don’t know the reason for these long-term situations,” Betts said.

Thomas said that without a clear understanding of why symptoms persist in some patients, it’s unclear whether a vaccine’s immune response would be beneficial or harmful.

“People who have chronic inflammatory conditions from Covid can fall into a category where you may not suddenly want to boost the immune system,” Thomas said. “But it might just make them better too. That’s how little we understand that.”

Betts said long haul may need to be assessed individually so doctors can weigh the potential risks and benefits. These patients will also need to be closely monitored and evaluated over time, he said.

“It could be a panel with judgments on a case-by-case basis,” Betts said. “We don’t really understand the long-term situation, so it’s difficult to try to predict how a vaccine will perform here.”