Recovered COVID-19 patients have developed stable immunity to COVID-19, study claims, MedicalXpress reported referring to a new study.
"A collaboration between the labs of Alessandro Sette, Dr. Biol. Sci. and Shane Crotty, Ph.D., at La Jolla Institute for Immunology is starting to fill in the massive knowledge gap with good news for vaccine developers and is providing the first cellular immunology data to help guide social distancing recommendations," the source noted.
The study involved 20 patients who underwent COVID-19 without severe complications and hospitalization.
The scientists found that all COVID-19 patients had a solid CD4, or "helper", T cell response, which helps antibody production. Almost all patients had produced virus-specific CD8, or "killer", T cells, which eliminate virus-infected cells.
Although these data do not exclude that the immune response to SARS-CoV-2 may be harmful to the body, they can serve as a marker of the effectiveness of experimental vaccines.
Another interesting fact: the researchers found that reactive T cells that recognize SARS-CoV-2 are present in blood samples from 2015 and 2018, long before the COVID-19 pandemic, although they never encountered it. The reason for the development of such cross-immunity may be the impact of other COVID-19 infections that cause the common cold.
However, it is still unclear whether the observed crossreactivity provides at least some level of preexisting immunity to SARS-CoV-2 and therefore could explain why some people or geographical locations are hit harder by COVID-19.
"Given the severity of the ongoing COVID-19 pandemic, any degree of cross-reactive coronavirus immunity could have a very substantial impact on the overall course of the pandemic and is a key detail to consider for epidemiologists as they try to scope out how severely COVID-19 will affect communities in the coming months," Crotty said.