According to a new study by MIT, based on the research at King’s College London, the immunity to Covid-19 may be short-lived. When the researchers studied 96 Covid-19 confirmed patients, they found that the virus-fighting antibodies were at their maximum about three weeks after the symptoms first appeared and then they rapidly reduced. In the majority of the patients with milder cases of Covid-19, there were no traces of antibodies at the end of three months. Antibodies were found higher and longer-lasting in patients with severe cases of infection.
This indicates that people may get reinfected repeatedly with Covid-19, just like how they could get infected with cold causing corona viruses. If that is the case, any protective antibodies would disappear with time and herd immunity to Covid-19 may never arrive even after one-shot vaccination or through community spread.
In the end, the study is only an indicative but not conclusive as there is an ongoing research of how T cells fight coronavirus in the absence of antibodies. In case if you don’t know, antibodies are the infection fighting white blood cells that attach on to the virus and prevent its entry into healthy cells while T cells are a type of white blood cells that can kill both the invading virus as well as the infected cells.