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People with COVID-19 developed at least ten times more antibodies after their first dose of vaccine than the average uninfected person who received two doses, new research shows.
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Another feasibility study also found that health workers who had COVID-19 responded to their first survey as most people respond to their second response.
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The researchers both suggested that post-COVID patients need only one shot to adequately protect them from the disease again.
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People usually report more side effects after their second coronavirus shot than their first.
But researchers from the Icahn School of Medicine on Mount Sinai discovered a slightly different response among patients who already had COVID-19.
Not only did these patients have stronger side effects – including fatigue, headaches, chills, fever and muscle / joint pain – but they also had more antibodies compared to those who had never been ill.
In a study still awaiting peer review on Monday, the researchers found that people who already had COVID-19 developed at least ten times more antibodies after their first dose than the average uninfected person who received two doses.
This may mean that previously infected individuals need only one shot to adequately protect them from becoming ill again. A single shot can also help them avoid more uncomfortable side effects after a second dose.
Indeed, the researchers wrote that ‘changing the policy of giving only one dose of vaccine to these individuals’ could save them from unnecessary pain and free up much-needed vaccine doses. ‘
The findings are supported by another preliminary study, which also appeared Monday, which found that health workers who previously had COVID-19 showed higher antibody levels after their first shot compared to individuals who had never been infected.
“It was a very big difference. It was something we could easily see,” said Dr. Mohammad Sajadi, associate professor at the Institute of Human Virology at the University of Maryland School of Medicine, told Insider.
Sajadi usually said that COVID-19 patients develop antibodies about two to three weeks after their initial infection. However, it did not take nearly as long before patients after COVID developed antibodies in response to a vaccine: the individuals showed high antibody levels a week after their first shot, with antibody levels peaking at about 10 to 14 after vaccination. had.
But both studies examined only a small group of vaccinated individuals – a few hundred in total. For this reason, many scientists are wary of prescribing anything other than the two-dose regimen tested in clinical trials.
“I’m a big supporter of the right dosage and right schedule, because that’s how the studies were done,” Maria Elena Bottazzi, an immunologist at Baylor College of Medicine, told The New York Times.
Patients after COVID have a ‘memory reaction’
Both Pfizer and Moderna’s late-stage clinical trials suggest that the vaccines are safe for individuals with a history of coronavirus infections. However, there are some exceptions.
The Centers for Disease Control and Prevention recommends that people with an active infection wait until their symptoms have disappeared – and the standard ten-day isolation period is over – before being vaccinated. This includes people who have already received their first dose.
“The recommendation for receiving any dose of the vaccine is not to get it if you were honestly ill at the time,” said Dr. Sandra Sulsky, an epidemiologist and principal at Ramboll, a global health science consulting firm, told Insider earlier.
But scientists are not yet sure when vaccines are needed for previously infected individuals. Emerging research suggests that antibodies to the coronavirus can last from months to several years – and even then the antibody level is not always related to immunity.
For example, all participants in the Sajadi study tested positive for coronavirus antibodies in July and August. By the time they shot, he said, some of them had ‘very, very low levels’ of antibodies, but they still appear to be responding strongly to the vaccine.
“What you are showing is that individuals who have had a previous COVID infection, which we call a recall reaction or a memory reaction,” Sajadi said. “For most infections, you need to have your micro a second time organism sees, responds faster. “
However, he warned that the findings only apply to people with a COVID infection – patients who have developed antibodies and have since recovered from their disease.
An interim solution for limited doses
Sajadi said giving only one dose to patients after COVID is a short-term strategy to address critical vaccine deficiencies.
With only 32 million Americans vaccinated so far, many states 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 close scheduling sites.
The CDC has now said that vaccination sites can delay the administration of a second dose up to six weeks – instead of the recommended three to four weeks – in ‘exceptional circumstances’ where it is not feasible to give the second dose on time.
“In times of vaccine shortage, where every dose of vaccine counts, we think the data show that you had a previous COVID infection, but that you only need one dose for the booster,” Sajadi said. . This “may even be the ideal scenario” for patients after COVID when there are many vaccinations available, he added.
So far, however, researchers have only investigated how patients respond to COVID to the Moderna and Pfizer vaccines, both of which use the same mRNA technology to elicit an immune response.
Sajadi said it was difficult to know whether patients after COVID would have a similar antibody response as the single-dose virus-vector vaccine from Johnson & Johnson, which plans to apply for emergencies this week.
“There is no reason to think it will act differently,” he said. “But you just never know before you test.”
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