A new study shows that antibodies to SARS-CoV-2 can be detected up to 7 months after the start of COVID-19

A new study led by Marc Veldhoen, principal investigator at the João Lobo Antunes Institute of Molecular Medicine (iMM; Portugal) with an interdisciplinary team of doctors and researchers from the Faculdade de Medicina da Universidade de Lisboa (FMUL) and the Centro Hospitalar Lisboa Norte ( CHLN) and collaborators from the Instituto Português do Sangue e Transplantação (IPST), show that 90% of the subjects have detectable antibodies 40 days to 7 months after recruitment COVID-19. These results, now published in the scientific journal European journal of immunology, also show that age is not a confounding factor in the levels of antibodies produced, but the severity of the disease is.

This comprehensive and cross-sectional study was thought in the first days of the pandemic, in March 2020. Researchers Patrícia Figueiredo-Campos and Birte Blankenhaus, first authors of this study, established a sensitive, specific and versatile internal COVID. 19 serology test. The optimization and validation of the assay was carried out as part of Serology4COVID, a consortium of 5 research institutes from Lisbon and Oeiras. In collaboration with doctors on the Hospital Santa María campus, the research team began monitoring the antibody levels of more than 300 COVID-19 hospital patients and healthcare workers, and more than 200 post-COVID-19 volunteers.

“Our immune system recognizes the virus SARS-CoV-2 as harmful and produces antibodies in response to it, which helps 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 symptoms of COVID-19 and, as expected, a reduction to intermediate levels thereafter, “explains Marc Veldhoen, adding that” in this early response phase, on average, men produce more antibodies than women, but levels equilibrate during the resolution phase and are similar between the sexes in the months after SARS-CoV-2 infection. ”In the acute phase of the immune response, the team observed higher levels of antibodies in subjects with more severe disease. Furthermore, the results show that age is not a confounding factor for antibody production, as no significant differences were observed between age groups. 90% of subjects have detectable antibodies up to 7 months after contracting COVID-19.

The research team then evaluated the function of these antibodies, that is, their neutralizing activity against the SARS-CoV-2 virus. In collaboration with the Instituto Português do Sangue e Transplantação (IPST), the research team analyzed the neutralizing capacity of the antibodies produced by patients and volunteers. “Although we observed a reduction in antibody levels over time, the results of our neutralization assays have shown strong neutralization activity up to the seventh month after infection in a large proportion of previously selected virus-positive subjects” explains Marc Veldhoen.

On the importance of this study, Marc Veldhoen states: “Our work provides detailed information for the tests used, which facilitates the longitudinal and additional analysis of the protective immunity against SARS-CoV-2. Importantly, there is a continued level of circulating neutralizing antibodies in most people with confirmed SARS-CoV-2. The next few months will be critical in assessing the robustness of the immune response to SARS-CoV-2 infection and finding clues for some open questions, such as the duration of circulating antibodies and the impact of reinfection. “

Reference: “Seroprevalence of anti-SARS – CoV – 2 antibodies in COVID – 19 healthy patients and volunteers up to six months after the onset of the disease” by Patrícia Figueiredo – Campos, Birte Blankenhaus, Catarina Mota, Andreia Gomes, Marta Serrano, Silvia Ariotti, Catarina Costa, Helena Nunes – Cabaço, António M. Mendes, Pedro Gaspar, October 21, 2020, European journal of immunology.
DOI: 10.1002 / eji.202048970

This study was carried out at the iMM in collaboration with the Biobank-IMM, the Academic Medical Center of Lisbon, the Faculty of Medicine of the University of Lisbon (FMUL), the Centro Hospitalar Lisboa Norte (CHLN) and the Instituto Português do Sangue e Transplantation (IPST). The SARS-CoV-2 protein used in serological tests was produced at the Institute for Experimental and Technological Biology (iBET) as part of the Serology4COVID consortium. This work was funded by the EXCELLtoINNOV project (No 667824) of the European Union H2020 ERA, the Foundation for Science, Technology and the Francisco Manuel dos Santos Society.