Re-infection from Covid-19 is rare, serious illness even rarer, a study of people in Qatar shows
Research published Wednesday in the New England Journal of Medicine shows that there are very few confirmed reinfections among the 353,326 people with Covid-19 in Qatar, and that reinfections are rare and overall. is light.
The first wave of infections in Qatar occurred between March and June 2020. Ultimately, about 40% of the population had detectable antibodies against Covid-19. The country then had two more waves from January to May 2021. This was before the more contagious delta variant.
To determine how many people became reinfected, scientists from Weill Cornell Medicine-Qatar compared the records of people with PCR-confirmed infections from February 2020 to April 2021. except for 87,547 people who were vaccinated.
The researchers found that among the remaining cases were 1,304 cases of reinfection. The average time between first illness and reinfection is about 9 months.
Of those who had re-infections, only four were severe enough to require hospitalization. There was no case of a person so sick that they had to be taken to the intensive care unit. Of the initial cases, 28 are considered critical. There were no deaths in the reinfection group, while there were seven deaths in the initial infection.
“When you have only 1,300 of those reinfections and four cases of infection,” said John Alcorn, an immunologist and professor of pediatrics at the University of Pittsburgh who was not affiliated with the study. seriously ill, that’s quite remarkable.
Research is limited. It was made in Qatar, so it’s not clear if the virus behaves the same way anywhere else. Work is done when alpha and beta variants are the cause of many reinfections. There are 621 cases of undetermined cause and 213 cases of “wild-type” virus. There is no mention of the delta variant, which is now the dominant strain. That could have an impact on the number of reinfections.
Alcorn’s own study of natural immunity found that antibody levels also differed significantly from person to person. Scientists still don’t know what protective antibody levels are, but in some cases, levels after infection may not be enough to keep someone from getting sick again.
“It is necessary to determine whether protection against severe disease upon reinfection lasts for longer periods, similar to that developed against other seasonal ‘cold’ coronaviruses. , confers short-term immunity against mild reinfection but longer-term immunity against more severe disease with reinfection. “If this is the case with SARS-CoV-2, the virus ( or at least variants studied to date) may adopt a more benign form of infection when it becomes endemic.”
Dr Kami Kim, an infectious disease expert not affiliated with this study, said people need to be careful not to get the false impression that people don’t need to be vaccinated if they already have Covid – 19.
“It’s like asking do you need airbags and seat belts?” Kim, director of the Department of Infectious Diseases & International Health at the University of South Florida. “Just because you have an airbag doesn’t mean wearing a seat belt won’t help, and vice versa. It’s good to have protection for both.”
It’s not worth it, Kim says, especially since the infection can have long-lasting effects. “The long-term incidence of Covid is much higher than the risk of vaccination,” Kim said.
In addition, vaccination not only protects an individual from getting sick, but also protects the community.
“Modern medicine is much better, cancer persists and autoimmune diseases thrive. Unless you’re too close, you don’t always know who is more susceptible to severe illness. and you can really put the people you care about in Kim says, “If you don’t get vaccinated, you can’t go back to a normal life.”
Limiting the number of diseases also limits the ability of more variants to develop, which may be even more dangerous than what is circulating today.
Alcorn says there’s another important lesson from the study.
“Vaccines are still our best method of getting to the right people who have been infected with this disease,” Alcorn said. “The main takeaway from this study here is that there is hope that through vaccination and through infection recovery we will get to a level where everyone has some degree of protection.”
