Dr. William Petri, a UVA professor of medicine who is engaged in research on COVID vaccines as well as the virus’ effects on the immune system, suggested that, given the gender-specific nature of most of the adverse effects reported, recommending different vaccines to men and women in the affected age groups might be a wise approach. “These two side effects can be avoided if women do not receive the J&J and Astrazeneca vaccines and men do not receive the mRNA vaccines. By way of contrast, one in 500 Americans has died from COVID-19,” he said.