A study by health workers suggests that people who already had COVID-19, even if they had no symptoms, could get away with a single dose of a two-dose coronavirus vaccine.
The researchers tested antibodies in the blood of 59 health workers who were vaccinated with the Pfizer or Moderna vaccines. Some of the volunteers had COVID-19 between eight and nine months before vaccination.
“Their bodies remembered it, no problem,” and they reacted very quickly to the vaccine, says Mohammad Sajadi, a doctor in infectious diseases from the Institute of Human Virology at the University of Maryland School of Medicine in Baltimore. After the first dose of vaccine, antibody levels increased rapidly in people who previously had symptoms with or without COVID-19, more than 500 times the levels seen in people who were never infected.
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These results, published on March 1 in JAMA, suggest that people who had COVID-19 could receive a shot or move to the end of the line for vaccines. It is estimated that 9 percent of people in the United States have confirmed cases of COVID-19. Limiting those people to a vaccine dose could release 4 to 5 percent of vaccine doses, Sajadi says.
“Immunologically it makes sense,” he says. "With the shortage of pandemics and ongoing vaccines, it also makes sense. The cost of inaction is too great not to save on vaccine doses when possible.
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