BALTIMORE — If you've previously been infected with COVID-19, a new study from the Institute of Human Virology at the University of Maryland School of Medicine and the Global Virus Network says you may only need a single dose of the vaccine.
Researchers compared the immune responses with both vaccines in healthcare workers diagnosed with COVID approximately six months earlier and found they had a much stronger immune response following their first shot compared to those not infected.
They found, in fact, that the immune response was similar to that typically seen on a second dose of vaccination. It also didn't differ whether they had an asymptomatic or severe symptoms of the virus, but groups had a robust immune response to the single shot.
“This secondary response we see to the first shot in those previously infected occurs through activation of memory B cells, a type of immune cell produced after exposure to a virus,” said study co-author Anthony Harris, MD, Professor of Epidemiology & Public Health at the University of Maryland School of Medicine. “Our study demonstrates for the first time that this recall response occurs after the first shot in those who were previously infected.”
They say that the healthcare workers who had never been infected had the expected antibody response to their first shot with lower levels of antibodies produced after the first shot and a more robust secondary response after their second immunization.
“Given the above findings that one dose of vaccine can elicit a recall response, and what we know about the duration of protective and memory responses, our preliminary findings suggest that a more evidence-based approach to immunizations would be to consider a single dose of vaccine for patients who have already had COVID-19. Public health officials may also want to consider placing these previously infected patients lower on the vaccination priority list,” said study co-author Mohammad Sajadi, MD, Associate Professor of Medicine in the UMSOM, physician-scientist at the Institute of Human Virology and a member of GVN.
To learn more about the study, click here.
