The study, which was published in the “New England Journal of Medicine” on Wednesday, which included 353,326 people who had previously been infected with the Corona virus in Qatar, showed that infection with Covid-19 again is rare, although its symptoms are generally mild.
Qatar faced the first wave of the outbreak of the Corona virus between March and June of 2020. With its end, it was found that the total rate of the population with antibodies to “Covid-19” amounted to 40%. Then, two successive waves hit the country between January and May 2021, before the emergence of the rapidly spreading “delta” mutator.
To determine how many people became infected again, scientists from Weill Cornell Medicine-Qatar compared records of confirmed infection by PCR tests between February 2020 and April 2021, excluding 87,547 people who received the vaccine.
Of the remaining cases, the researchers found that 1,304 people became infected again. The average time between the two injuries was about 9 months. Among these, 4 severe cases that required hospitalization, while no cases of severe disease requiring treatment in intensive care units were recorded.
Returning to the basic cases, 28 were placed in the “critical” category, and no deaths were recorded among the group that was infected again, compared to the death of 7 people among those who were infected for the first time.
In this regard, John Alcorn, an expert in immunology and professor of pediatrics at the University of “Pittsburgh” who was not involved in the study, commented, “It is wonderful to have 1,300 infections for the second time among so many people, and 4 cases of the disease.” severe.”
However, this study has limitations, in that it was conducted in Qatar, so it is not possible to predict whether the spread of the virus will be similar elsewhere. It was conducted during an outbreak of “alpha” and “beta” mutant, which caused many cases of re-infection. Also, 621 cases were not identified, and 213 cases were infected with a “wild” virus.
The study also did not mention the “delta” variant, which is now the dominant strain, and this could have an effect on the number of re-infections.
Previous studies have shown that natural immunity reduces the risk of infection. One of them, conducted in Denmark and published in March, found that most people who were infected with “Covid-19” enjoyed protection from infection again that lasted more than 6 months, but those who were infected a second time were mostly within the age group 65 years and over. above.
However, this study, like the new one that was conducted in Qatar, is the presumed term of protection.
Alcorn’s own research on innate immunity shows that antibody levels also vary widely from person to person. Scientists do not yet know what level of antibodies is needed to provide protection, and the levels of these antibodies recorded after infection are sometimes not enough to prevent someone from getting sick again.
A specialist in infectious diseases not participating in the study, Dr. Kami Kim, said that people should be careful that they form a false impression that they do not need to receive the vaccine if they have previously been infected with “Covid-19”.
Kim indicated that it is not worth risking your chances with the disease, especially since infection may have long-term effects, noting that vaccination not only prevents the individual from contracting the disease, but also protects the community.
Alcorn pointed to an important conclusion drawn from this study, which is: “Through vaccination and recovery from disease, we will reach a level where everyone enjoys some protection.”