COVID-19 immunity Question

Corona Virus survivors may only be protected from reinfection for almost six months , according to a study which casts doubt over the prospect of long-lasting immunity. University of Amsterdam researchers followed 10 volunteers for 35 years and tested them every month for four seasonal and weaker Covid-19, which usually cause mild illnesses similar to the common cold. They found those who had been infected with the strains — from the same family as SARS-CoV-2, the type that causes Covid-19 — had “an alarmingly short duration of protective immunity”.