A team of researchers from the Finnish Institute for Health and Welfare, Finland revealed that the neutralizing anti-bodies generated after COVID-19 infection persist for at least a year.
The study conducted by a team of researchers on COVID-19 recovered individuals to determine how long the antibodies generated are effective and if these antibodies are capable of preventing re-infection. The researchers considered over 360 recovered COVID-19 patients or individuals for this study. Additionally, 13% among these individuals suffered from severe COVID-19 infection and required hospitalization. The researchers identified and measured the proportion of anti-spike immunoglobulin G (S-IgG), anti-nucleoprotein IgG (N-IgG), and neutralizing antibodies (NAb). They examined the presence of serum antibodies at six and twelve months after diagnosis in severely affected COVID-19 recovered individuals. They also studied and interpreted NAb titers against severe acute respiratory syndrome coronavirus-2 variants of concern such as B.1.1.7 (Alpha), B.1.351 (Beta), and others. In this context, it is significant to note that the coronavirus uses the viral spike protein or S-protein to infect host cells and is also the main target of antibodies after infection or vaccination. NAb generated against SARS-CoV-2 target the receptor-binding domain of the S- protein and prevent it from attaching to the host cell. They found that NAb against COVID-19 persisted in approximately 90% of the COVID-19 recovered individuals for at least a year. Moreover, SARS-CoV-2 has undergone mutations that are causing concerns in terms of viral transmission and its potentiality to escape from either vaccine-induced immunity or infections. However, it is alarming that neutralizing capacity against the variants of concern such as Alpha, Beta, and others reported in the U.K., South Africa, and others was significantly lower.
Taken together, the study suggests that protection against re-infection is long-lived in COVID-19 recovered individuals. However, the study concludes that re-infection is possible in the absence of neutralizing anti-bodies.