There are two recent studies that suggest that immunity lasts for at least a year and it is possible that it may last for decades, at least for some people. These studies have been made on bone marrow of the persons who have been infected by Corona virus Sars-CoV-2.
The first study on Persistent Cellular Immunity to SARS-CoV-2 Infection is as under:
SARS-CoV-2 is responsible for an ongoing pandemic that affected millions of individuals around the globe. To gain further understanding of the immune response in recovered individuals we measured T cell responses in paired samples obtained an average of 1.3 and 6.1 months after infection from 41 individuals. The data indicate that recovered individuals show persistent polyfunctional SARS-CoV-2 antigen specific memory that could contribute to rapid recall responses. In addition, recovered individuals show enduring immune alterations in relative numbers of CD4+ and CD8+ T cells, expression of activation/exhaustion markers, and cell division.
Summary We show that SARS-CoV-2 infection elicits broadly reactive and highly functional memory T cell responses that persist 6 months after infection. In addition, recovered individuals show enduring immune alterations in CD4+ and CD8+ T cells compartments.from Biorxiv.com
The above report is a pre-print and has not been peer reviewed. A similar such report has been submitted to Nature.Com by another group of scientists which opines as under:Continue reading