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When the topic is the new coronavirus (SARS-CoV-2), many topics are still far from a consensus among experts, such as the case of long-lasting immunity (or not) against COVID-19 and cases of reinfection. Now a group of Portuguese researchers has found that 90% of people have detectable antibodies between 40 days and 7 months after contracting the viral infection, demonstrating some degree of longer-lasting immunity.
The positive point is that the investigation, which began in March, must continue, since these are preliminary results and only the analyzes of the coming months will be able to give a more definitive answer on the duration of immunity against the new coronavirus. At this point, it is important to remember that humanity has been facing COVID-19 for less than a year.
Directed by Marc Veldhoen, a researcher at the João Lobo Antunes Institute of Molecular Medicine (iMM), the full investigation was published in the European Journal of Immunology. In addition to the presence of antibodies, studies that followed nearly 500 positive patients show that age is not a determining factor for antibody production, only for the severity of COVID-19.
COVID-19 and antibodies
Made from serological tests, the Portuguese study was still thought of in the first days of the epidemic in the country, in March of this year. Since then, the team of researchers has monitored the antibody levels of more than 300 hospital patients and healthcare professionals diagnosed with COVID-19, 2,500 employees at a local university, with no initial confirmation of coronavirus infection, and 198 volunteers already they have done. he had recovered from the illness.
“Our immune system recognizes the SARS-CoV-2 virus as harmful and produces antibodies in response to it, which helps fight the virus,” says Veldhoen, who now wants to understand how long these antibodies stay active and promote protection. of the organism.
“The results of this 6-month cross-sectional study show a classic pattern with a rapid rise in antibody levels in the first three weeks after COVID-19 symptoms and, as expected, a reduction to intermediate levels thereafter. “Veldhoen explains. “In this initial response phase, men produce, on average, more antibodies than women, but the levels are balanced during the resolution phase and are similar between the sexes in the months after SARS-CoV-2 infection. “, adds the researcher.
In the acute phase of the immune response, when the patient needs a better immune response against the infectious agent to ensure survival, the team observed higher levels of antibodies in individuals with more severe disease, as expected.
Antibodies continue to protect
Another objective of the study was to know the neutralizing capacity of these antibodies against the coronavirus and, for this, the team had the collaboration of the Portuguese Institute of Blood and Transplants (IPST). “Although we have seen a reduction in antibody levels over time, the results of our neutralization tests showed strong neutralization activity up to the seventh month after infection in a large proportion of individuals who previously tested positive.” Veldhoen says.
“Our work provides detailed information for the assays used, facilitating a subsequent longitudinal analysis of protective immunity against SARS-CoV-2. It is important to note that it highlights a continuous level of circulating neutralizing antibodies in most people with SARS-CoV-2 confirmed. The next few months will be critical in assessing the robustness of the immune response to SARS-CoV-2 infection and finding clues to some open questions, such as the duration of circulating antibodies and the impact of reinfection. ”Adds the Portuguese researcher.
To access the full article, published in the European Journal of Immunology, click here.
Source: EurekAlert!
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