People who had COVID-19 may develop 10 times more antibodies after a single dose of vaccine

• People who had COVID-19 developed at least 10 times more antibodies after their first dose of the vaccine than the average uninfected person who received two doses, new research shows.

• Another preliminary study also found that healthcare workers who had COVID-19 responded to their first stroke the same way most people respond to their second.

• Researchers have both suggested that post-COVID patients may only need one hit to protect them from the disease again.

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People typically report more side effects after their second coronavirus injection than their first.

But researchers at the Icahn School of Medicine at Mount Sinai have found a slightly different response in patients who already had COVID-19.

These patients not only had stronger side effects – including fatigue, headache, chills, fever, and muscle / joint pain – after their first injection, but they also had more antibodies than those who had never before been injected. sick before.

In a study Monday that is still awaiting peer review, researchers found that people who already had COVID-19 developed at least 10 times more antibodies after their first dose than the average uninfected person who had received two doses.

This could mean that people previously infected only need one vaccine to sufficiently protect them against a new disease. One shot can also help them avoid more uncomfortable side effects after a second dose.

Indeed, the researchers wrote that “changing the policy to give these people only one dose of vaccine” could “save them unnecessary pain and release many urgently needed doses of vaccine.”

The results are supported by another preliminary study, also released on Monday, which found that healthcare workers who previously had COVID-19 had higher levels of antibodies after their first vaccine compared to those vaccinated who did not. ‘had never been infected.

“It was a really big difference. It was something we could easily see,” Dr. Mohammad Sajadi, associate professor at the Institute of Human Virology, University of Maryland School of Medicine, told Insider. .

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Typically, Sajadi says, COVID-19 patients develop antibodies around two to three weeks after their initial infection. But it didn’t take that long for post-COVID patients to develop antibodies in response to a vaccine: Individuals showed elevated antibody levels a week after their first vaccine, with antibody levels peaking around days 10 to 14 after vaccination.

But both studies only looked at a small group of vaccinated individuals – a few hundred in total. For this reason, many scientists are reluctant to prescribe anything other than the two-dose regimen tested in clinical trials.

“I’m a big believer in the right dosage and timing, because that’s how the studies were done,” Maria Elena Bottazzi, immunologist at Baylor College of Medicine, told The New York Times.

Post-COVID patients have a ‘memory response’

Advanced clinical trials from Pfizer and Moderna suggest the vaccines are safe for people with a history of coronavirus infections. There are, however, a few exceptions.

The Centers for Disease Control and Prevention recommends that people with an active infection wait until their symptoms have resolved – and the standard 10-day isolation period – before getting vaccinated. This includes people who have already received their first dose.

“The recommendations for receiving any dose of the vaccine are not to get it if you are frankly ill at the time,” Dr Sandra Sulsky, epidemiologist and director at Ramboll, a global company, previously told Insider. health science consultancy.

But scientists still don’t know when vaccines are needed for those previously infected. Emerging research suggests that antibodies to the coronavirus could last anywhere from months to years – and even then, antibody levels do not always correlate with immunity.

All participants in Sajadi’s study, for example, tested positive for antibodies against the coronavirus in July and August. By the time they got the vaccine, he said, some of them had “very, very low levels” of antibodies – but they still seemed to have a strong response to the vaccine.

“What this shows you is that people who had previously had a COVID infection have what we call a callback response or a memory response,” Sajadi said. “For most infections the second time you see this microorganism you should get a faster response.”

He warned, however, that the results only apply to people with “common COVID infection” – patients who have developed antibodies and have since recovered from their illness.

A temporary solution in limited doses

Sajadi said giving a single dose to post-COVID patients is a short-term strategy to address critical vaccine shortages.

With only 32 million Americans vaccinated to date, many states continue to report that they do not have enough doses to meet demand. In recent weeks, some local health departments have even been forced to cancel vaccine appointments or shut down scheduling websites.

The CDC has now said that vaccination sites can delay a second dose for up to six weeks – instead of the recommended three to four weeks – in “exceptional circumstances” where it is not possible to give the second dose on time.

“In times of vaccine shortage, where every dose of vaccine counts, we believe the data shows that if you’ve had a COVID infection in the past, you may only need one dose for the booster.” , Sajadi said. This “may even be the ideal scenario” for post-COVID patients when vaccines are widely available, he added.

So far, however, researchers have only looked at how post-COVID patients respond to Moderna and Pfizer vaccines – both of which use the same mRNA technology to trigger an immune response.

Sajadi said it was unclear whether post-COVID patients will develop an antibody response similar to the single-dose viral vector vaccine from Johnson & Johnson, which plans to seek emergency use this week.

“There is no reason to think it would act any differently,” he said. “But you never know until you’ve tested.”

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Originally published February 2, 2021 at 6:27 pm