(CNN) – When people are re-infected with COVID-19, their chances of ending up in the hospital or dying are 90% lower than the initial infection with COVID-19, according to the New study.
The study, published Wednesday in the New England Journal of Medicine, found that there were few confirmed infections among 353,326 people who contracted COVID-19 in Qatar, and infections again were rare and generally mild.
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. Then the country experienced two more waves from January to May 2021. This was before the most contagious deltas.
To determine how many people were infected again, scientists at Weill Cornell Medicine Qatar compared records of people with confirmed PCR infections between February 2020 and April 2021. They excluded 87,547 people who received the vaccine.
The researchers found that among the remaining cases, 1,304 infections were again present. The median time between first illness and reinfection was about 9 months.
Of those who re-infected, only four were severe enough to go to hospital. There have been no cases where people were sick enough to need treatment in the intensive care unit. Of the initial cases, 28 were considered critical. There were no deaths among the re-infected group, while there were seven deaths in the primary infections.
“When there are only 1,300 infections out of that many people and four cases of severe illness, that’s amazing,” said John Alcorn, an expert in immunology and professor of pediatrics at the University of Pittsburgh, who was not involved in the study.
Study has limits. It was made in Qatar, so it is not clear if the virus will behave in the same way elsewhere. The work was done when the alpha and beta variants caused many infections again. There were 621 unidentified and 213 ‘wild-type’ virus cases. The delta variant, which is now the dominant strain, is not mentioned. This could have an impact on the number of reinfections.
Previous studies Shown that natural immunity reduces the risk of infection.
a study conducted in Denmark and published in March found that most people who contracted COVID-19 appeared to be protected against reinfection which had been stable for more than six months. But demographic examination of those who became infected again showed that they were mostly people 65 years of age or older. This study does not explain how long the protection will last, nor does the new Qatar study.
Alcorn’s own research on natural immunity shows that antibody levels also vary widely from person to person. Scientists do not yet know what the level of protective antibodies is. But in some cases, levels after infection may not be enough to prevent someone getting sick again.
“It is necessary to determine whether this protection from severe illness at the time of reinfection lasts longer, similar to the immunity that develops against other seasonal coronaviruses from ‘common colds’. It produces short-term immunity against mild infection but for a longer period. – Immunity to more serious diseases as infection returns.” “If this is the case for SARS-CoV-2, the virus (or at least the variants studied so far) could adopt a milder pattern of infection when it becomes endemic.”
Never get the wrong impression about re-infection and vaccinations
Dr Kami Kim, an infectious disease specialist who is not affiliated with this study, said people should be careful not to get the wrong impression that this means people do not need to be vaccinated if they are sick with the coronavirus. .
“It’s like asking if you need airbags and seat belts,” said Kim, director of the University of South Florida’s Division of Infectious Diseases and International Medicine. “The fact that you have airbags doesn’t mean that seat belts won’t help you and vice versa. It’s good to have protection for both.”
Kim said the illness was not worth the risk, especially since the infection could have long-term effects. “happening prolonged covid It’s much greater than the risk of receiving a vaccine, Kim said.
Moreover, vaccines not only protect the person from contracting the disease, but also the society.
“Modern medicine is so much better, people get cancer and really survive autoimmune diseases and thrive. Unless you’re very close, you don’t always know who’s at risk for more serious diseases. And you can literally turn people away. You’re in danger if you get sick and expose them,” Kim said. “Without vaccination, you cannot return to a normal life.”
Vaccines to reduce the possibility of variants
Reducing the number of diseases also limits the possibility of developing more variants, which can be more dangerous than those currently circulating.
There is another important lesson from this study, Alcorn said.
“Vaccines are still the best way we have to get to the same place where these people got infected,” Alcorn said. “The main conclusion of this study here is that there is hope that by vaccinating and curing the infection, we will get to the level where each individual has a certain level of protection.”