T cells are not critical for recovery of primates from acute COVID-19 infections, study reveals New research conducted in monkeys reveals that T cells are not critical for the recovery of primates from acute COVID-19 infections. T cell depletion does not induce severe disease, and T cells do not account for the natural resistance of rhesus macaques to severe COVID-19. Furthermore, strongly T cell-depleted macaques still develop potent memory responses to a second infection. The findings, published in the mBio, an open-access journal of the American Society for Microbiology, have implications for the development of second-generation vaccines and therapeutics. We started this study early in the pandemic, trying to figure out how to make a good model to study the disease in humans using animals. The monkeys turned out to be more resistant to the disease than we expected, so we wanted to try to figure out why that was and try to gain some insights into the disease in humans as well. We now know that the antibody response is the most critical response for protection by vaccination, not the T cell response."