Studies say reinfection lowered by having virus AP Two new studies give evidence that having COVID-19 might offer some protection against future infections. Researchers found that people who made antibodies to the novel coronavirus were much less likely to test positive again for up to six months and maybe longer. The results bode well for vaccines, which provoke the immune system to make antibodies — substances that attach to a virus and help it be eliminated. A medical worker, left, takes a sample from a man for a COVID-19 test at the Institute of Virology, Vaccines and Sera-Torlak in Belgrade yesterday.