SARS-CoV-2 antibodies that are detectable up to seven months after the...

A new study led by Marc Veldhoen, principal researcher at the Instituto de Medicina Molecular João Lobo Antunes (iMM; Portugal), with an interdisciplinary team of clinicians and researchers from the Faculdade de Medicina of the Universidade de Lisboa (FMUL) and the Centro Hospitalar Lisboa Norte (CHLN) and employees of the Instituto Português do Sangue e Transplantação (IPST) show that 90% of the test subjects have detectable antibodies 40 days to 7 months after the COVID-19 infection. These results have now been published in the journal European Journal of Immunologyalso show that age is not a factor in the amount of antibodies produced, but the severity of the disease.

This comprehensive cross-sectional study was already conceived in the early days of the March 2020 pandemic. Researchers Patrícia Figueiredo-Campos and Birte Blankenhaus, first authors of this study, set up an internal, sensitive, specific and versatile study on the COVID-19 serology test. The optimization and validation of the assay was carried out by Serology4COVID, a consortium of 5 research institutes in Lisbon and Oeiras. Working with doctors on the Santa Maria Hospital campus, the research team began monitoring the antibody levels of over 300 COVID-19 hospitalized patients and healthcare workers, and over 200 volunteers following COVID-19.

“Our immune system recognizes the SARS-CoV-2 virus as harmful and, in response, produces antibodies that help fight the virus.” “The results of this 6-month cross-sectional study show a classic pattern with a rapid rise in antibody levels within the first three Weeks after the COVID-19 symptoms and, as expected, a reduction to medium levels thereafter, ”explains Marc Veldhoen, adding“ In this early reaction phase, men produce on average more antibodies than women, but the levels even out during the dissolution phase and are in similar to the months after SARS-CoV-2 infection between the sexes. ”In the acute phase of the immune response, the team observed higher antibody levels in patients with more severe disease. The results also show that age is not a disruptive factor in the production of antibodies, as no significant differences between the age groups were observed. Globally, 90% of test subjects have detectable antibodies up to 7 months after the COVID-19 infection.

Next, the research team evaluated the function of these antibodies, ie their neutralizing activity against the SARS-CoV-2 virus. In collaboration with the Instituto Português do Sangue und Transplantação (IPST), the research team analyzed the neutralization capacity of the antibodies produced by patients and volunteers. “Although we observed a decrease in antibody levels over time, the results of our neutralization tests showed robust neutralization activity up to the seventh month after infection in a large proportion of the test subjects who had previously been tested as virus-positive,” explains Marc Veldhoen.

Marc Veldhoen explains the importance of this study: “Our work provides detailed information on the assays used and facilitates the further and longitudinal analysis of the protective immunity against SARS-CoV-2. Importantly, in most cases, a persistent level of circulating neutralizing antibodies is highlighted in people with confirmed SARS-CoV-2. The next few months will be crucial in assessing the robustness of the immune response to SARS-CoV-2 infection and finding clues to some open questions, such as: B. the duration of the circulating antibodies and the effects of reinfection. ”

Follow the latest news on the Coronavirus (COVID-19) outbreak

More information:
Patrícia Figueiredo-Campos et al., Seroprevalence of anti-SARS-CoV-2 antibodies in COVID-19 patients and healthy volunteers up to six months after the onset of the disease, European Journal of Immunology (2020). DOI: 10.1002 / eji.202048970

Provided by the Instituto de Medicina Molecular