PARIS, April 4 (Benin News) –
Antibodies to SARS-CoV2 become undetectable in serological tests in 43.3% of patients seven months after infection, according to a study by the Centro de Investigación Biomédica en Red (CIBER), which analyzed the evolution of levels of IgG in the population, as part of the national sero-epidemiological study of SARS-CoV-2 (ENE-COVID).
The researchers explain that IgG is the predominant class of immunoglobulins in the body and is found in blood and other fluids. It is an antibody that protects against bacterial and viral infections and develops in a specific way several days after infection.
The ENE-COVID study group, in which members of CIBER from the fields of infectious diseases and epidemiology and public health (CIBERINFEC and CIBERESP) and ISCIII (National Center for Microbiology and National Center for epidemiology), took advantage of the possibilities of this sero-epidemiological project to analyze the evolutionary trends in the detection of IgG against protein N by immunoassay in the four rounds of the ENE-COVID study, carried out over a period of seven months, between April and November 2020. Of the 7400 people who participated in the four rounds, a total of 2595 (35.1%) were positive for anti-nucleocapsid IgG in at least one round.
“In 43.3% of patients who tested positive in the first round, anti-nucleocapsid IgGs became undetectable after seven months. This high percentage may be due to the fact that most of the positive patients in our cohort were asymptomatic (about one third of the participants) or had mild infections, which would lead us to conclude that the IgG response is heterogeneous and conditioned by the severity of the disease. infection”, detailed the scientific director of CIBERINFEC and one of the coordinators of this study, Jesús Oteo.
The study confirmed that a significant percentage of patients infected with SARS-CoV-2 may have negative serological test results within months of infection. However, “this finding is not necessarily indicative of reduced immunity against SARS-CoV-2 since immune memory associated with T and B cells can generate long-term protection, as is the case for d other infectious diseases,” he said.