Study says Covid-19 antibodies can last up to seven months

One of the questions that has raised the most interest and research on the part of the scientific community, since the beginning of the pandemic, is to understand if the organisms of patients with covid-19 are able to have an adequate immune response and how long this immunity can last. Now, a new American study has revealed that antibodies, which protect the body from being infected with the new coronavirus, can last up to seven months.

Researchers at the University of Arizona, in the United States, followed for 6,000 patients infected with the new coronavirus for months and found that antibodies against Sars-CoV-2 can remain present in the blood for a period of at least five to seven months.

Recently, cases of reinfected people have been confirmed who, according to the Spanish newspaper El País, showed more severe symptoms when they became ill with covid-19 for the second time – examples that raise doubts for the scientific community when talking about immunity. Over the past few months, several studies have been released showing that antibodies – proteins of the immune system that prevent the virus from infecting the body’s cells – against the new coronavirus were decreasing after a few months after infection, especially in people who had mild symptoms. . There are several theories and even more doubts. But the question remains: are people protected after the first infection? The North American study, published on Tuesday (20) in the scientific publication Immunity, and considered one of the largest performed so far, for having analyzed about 6 thousand people, indicates that yes: who has already been infected with the new coronavirus can have immunity for at least seven months.

“Our study shows that it is possible to generate lasting immunity against this virus,” he explained to the Spanish newspaper Deepta Bhattacharya, a researcher at the University of Arizona and co-author of the work.

“In the moderate infections that we analyzed, the antibody response seems quite conventional. The levels of these proteins rise first, then fall and eventually stabilize,” he continued. As for reinfections, the researcher explains that it can happen but that they are “exceptional” cases.

When a virus infects the body, the immune system produces short-lived plasma cells, which produce antibodies to immediately fight the pathogen. These antibodies appear in the blood, normally, up to 14 days after infection and, according to the study’s author, some of them “are very sophisticated”, being able to memorize a pathogen forever and develop molecular weapons to destroy it, including different types of antibodies. high power.

Study

The North American study resulted from a testing campaign involving 30,000 people. The researchers, however, analyzed and monitored 5,882 of these people, studying the production of neutralizing antibodies in more than 1,000.

The prevalence of infections is low, with only about 200 people who transmitted the virus and produced neutralizing antibodies, explained Bhattacharya.

“If antibodies provide long-lasting protection against the new coronavirus has been one of the most difficult questions to answer, this investigation has not only given us the ability to accurately test antibodies against covid-19, but also the knowledge that long-lasting immunity it is a reality”.

By analyzing the blood of volunteers who tested positive for the new coronavirus, the scientists found that the antibodies were present at viable levels for a period of at least five to seven months. However, the maximum the team was able to go back in time to see the duration of the antibodies was precisely seven months, since the epidemic arrived relatively later in Arizona.

“We were only able to test six people who were infected about seven months ago, but we have many others infected three, four, five months ago,” said the researcher. “We don’t have a crystal ball to know how long the antibodies last, but based on what we know about other coronaviruses, we expect the immune response to be maintained for at least seven months, and probably for much longer.”

“We know that people who were infected with the first Sars coronavirus, which is the most similar to Sars-CoV-2, are still able to be immune 17 years after infection,” added Bhattacharya. “If Sars-CoV-2 looks like the first, we expect the antibodies to last at least two years, and any much shorter period would be unlikely [do que isso].” (Agency Brazil)