Reinfection by covid-19 may occur with stronger symptoms, according to a study released this Wednesday by the Oswaldo Cruz Foundation, the largest scientific research center in Brazil and Latin America.
According to the study, to be published in May in the journal ‘Emerging Infectious Desease’, people who were mildly infected with the virus and who did not need to be hospitalized will not have produced an immune response, thus increasing the possibility of reinfection. even with the same variant that infected them the first time.
According to the investigation, if a patient was reinfected by the same strain “it is because it would not have created an immunological memory” and, if it had been for another variant, this would be because it would “escape” surveillance and would not be recognized by the previously generated memory , for being a little different.
To reach these conclusions, the researchers followed a group of 30 people weekly since the beginning of March 2020 – when the pandemic had just arrived in Brazil – until the end of the year. Of these, four contracted Sars-CoV-2 and some were reinfected for the same variant.
In all four cases, the first infection occurred with mild symptoms, while in the second contagion the symptoms were more frequent and stronger, but did not require hospitalization.
“These people did not, in fact, have detectable immunity until after the second infection. This suggests that for a part of the population that had the disease in a mild way, it is not enough to be exposed to the virus, but more than one, to have a degree of immunity, “explained Thiago Moreno, a researcher at the Center for Technological Development in Health at Fiocruz and coordinator of the study.
Although so far only the possibility of contracting covid-19 has been studied twice, Moreno does not rule out that a third may occur.
“We don’t know how long post-covid immunity lasts. A person could be vulnerable to a new reinfection or even to contract a different variant,” he said.
Researchers from the Federal University of Rio de Janeiro (UFRJ), the D’Or Institute for Education and Research (Idor) and the Chinese company MGI Tech Co. also participated in the study.
The covid-19 pandemic caused at least 2,874,984 deaths worldwide, resulting from more than 132.3 million cases of infection, according to a report made by the French agency AFP.
Brazil, which is going through its most critical moment in the pandemic with successive records of deaths and cases, totals 340,776 deaths and 13,193,205 diagnoses of infection since the first case was registered in the country, about 13 months ago.