A recent study has shed light on reinfections of COVID-19, revealing that they tend to clear faster than initial infections, including individuals who have never received a COVID-19 vaccine.
The research, conducted by U.S. and British scientists, analyzed data from 1,796 initial infections and 193 reinfections.
They discovered that those who experienced a second infection cleared the illness in an average of 6.6 days, as opposed to 9.3 days for their initial bout with the virus.
This trend was consistent, even in a subset of 71 individuals who had well-documented cases of both their initial and reinfection, where clearance time decreased from 9.2 days to 6.3 days.
The study suggests that immunity from a first infection affects the speed at which the virus is cleared in a second infection, thus shortening the overall duration of acute illness.
The researchers, including Dr. Yonatan Grad from the Harvard T.H. Chan School of Public Health, propose the existence of additional immunological mechanisms that influence one’s immune response to SARS-CoV-2 across sequential infections.
The analysis was based on COVID-19 tests from members of the National Basketball Association and its affiliates over a span of more than two years, from March 11, 2020, to July 28, 2022. It’s worth noting that the population primarily consisted of young, healthy males, though adjustments were made for age.
The study also delved into vaccination status, finding that most individuals with documented infections had received a vaccine. Among the 1,796 initial infections, 1,095 were in vaccinated individuals, with some having received a booster.
A mere 127 were unvaccinated. In contrast, of the 193 reinfections, 160 individuals were vaccinated, while only eight were unvaccinated.
Interestingly, the researchers did not detect significant differences in viral kinetics between the vaccinated and unvaccinated groups. This includes factors like clearance time and peak viral concentration. Moreover, the kinetics of reinfection did not vary significantly based on the virus variant.
The study’s funding came from the U.S. Centers for Disease Control and Prevention, Yale University, the National Basketball Players Association, and the U.S. National Institutes of Health. There were disclosures of researchers having consulting agreements with the National Basketball Association, Moderna (the manufacturer of a COVID-19 vaccine), and the league.
This research supports the notion that our immune systems clear SARS-CoV-2 faster upon a second encounter, providing valuable insights into the dynamics of COVID-19 reinfections.