CD4 and infection: These observations may appear in partial contrast with two previous studies, which described comparable SARS-CoV-2-specific T-cell and humoral responses between HIV-positive and negative individuals after SARS-CoV-2 infection [15,16]; however, PWH of our cohort have a history of late HIV presentation and feature lower median CD4+ and CD4+/CD8+ ratio than those included in the abovementioned studies, which may be responsible for reduced T-cell responses to SARS-CoV-2 natural infection.