Importantly, whereas most of these studies adjusted their analyses for age, sex, ethnicity, and comorbidities, many of these were conducted as part of general COVID-19 population-based studies, and often did not have detailed data available on potentially relevant HIV-related parameters, such as use and type of antiretroviral therapy, plasma HIV-RNA levels, prior AIDS diagnoses, and current and nadir CD4+ cell counts. This evidence concerns the gene CD4 and COVID-19.