When people got reinfected with Covid-19, their odds of ending up in the hospital or dying were 90% lower than an initial Covid-19 infection, according to a new study.
The study published Wednesday in the New England Journal of Medicine found that there were few confirmed reinfections among 353,326 people who got Covid-19 in Qatar, and the re-infections were rare and generally mild.
The first wave of infections in Qatar struck between March and June of 2020. In the end about 40% of the population had detectable antibodies against Covid-19. The country then had two more waves from January through May of 2021. This was prior to the more infectious delta variant.
To determine how many people got reinfected, scientists from Weill Cornell Medicine-Qatar compared the records of people with PCR-confirmed infections between February of 2020 and April 2021. They excluded 87,547 people who got the vaccine.
Researchers found that among the remaining cases there were 1,304 reinfections. The median time between the first illness and reinfection was about 9 months.
Among those with reinfections, there were only four cases severe enough that they had to go to the hospital. There were no cases where people were sick enough that they needed to be treated in the intensive care unit. Among the initial cases, 28 were considered critical. There were no deaths among the reinfected group, while there were seven deaths in the initial infections.
“When you have only 1,300 reinfections among that many people, and four cases of severe disease, that’s pretty remarkable,” said John Alcorn, an expert in immunology and a professor of pediatrics at the University of Pittsburgh who was not affiliated with this study.
