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In a study of mild-to-moderate COVID-19 patients, scientists established that the level of certain antibodies remained stable for five months.
Researchers have found that in patients with mild to moderate COVID-19, SARS-CoV-2 specific antibody titers remain stable for about five months, contradicting previous research suggesting that the same neutralizing antibodies may decline after just eight weeks.
Ania Wajnberg and her colleagues said that while their study does not provide conclusive evidence that these levels protect against reinfection, they “believe they are very likely to decrease the odds ratio for reinfection and may attenuate disease in the event of infection. irruptive “.
According to the researchers, as the number of daily COVID-19 cases continues to increase worldwide, understanding the humoral immune response, which includes the antibody response, in mild and asymptomatic cases is particularly important as these represent most infections. .
In March 2020, Mount Sinai Health System in New York City, USA, began screening people for antibodies to SARS-CoV-2 to recruit donor volunteers for plasma therapy. convalescent. As of October 6, Mount Sinai had screened 72,401 individuals, with a total of 30,082 individuals testing positive, many with notable IgG antibody responses. In a study published in Sciences, Wajnberg and their colleagues studied this cohort to analyze the longevity and potency of their anti-SARS-CoV-2 antibody responses.
Using a well-established assay, in which SARS-CoV-2 peak (S) protein binding roughly correlates with virus neutralization, they evaluated the neutralizing effects of the antibodies.
To assess the longevity of the antibody response, the authors recalled 121 plasma donors. In these patients, they found stable antibody titers over a period of approximately five months. This contradicts the findings of other researchers, who observed that antibody responses do not have much longevity, including work published in June 2020 that showed decreasing titers eight weeks after infection with the virus. The team reported that one of the differences that may explain this difference is that the antibodies they were measuring point to a different viral antigen; therefore, they suggest that the stability of the antibody response over time depends on the target antigen.
The researchers intend to follow this cohort for longer intervals to help inform whether and how long-lasting antibody responses protect against reinfection. They believe that the findings from this future project could inform policy regarding the pandemic and be beneficial to vaccine development efforts.
