The included covariates were SARS-CoV-2 vaccination, infection period, years of HIV infection, HIV-RNA at the time of SARS-CoV-2 infection, nadir CD4+ T cells (stratified by terciles), CD4+, CD8+ T cells and CD4+/CD8+ ratio at the time of SARS-CoV-2 infection (stratified by terciles), sex, age, number of comorbidities and ethnicity. Here, CD4 is linked to HIV infectious disease.