Baseline spouse testing in newly diagnosed people living with human immunodeficiency virus in China from 2011 to 2020: a nationwide, retrospective study

Heterosexual contact is a major route for transmitting human immunodeficiency virus (HIV), and spousal transmission accounts for a considerable proportion of cases, indicating the need for timely spousal HIV counseling and testing (HCT) to reduce transmission rates, especially in spousal relationships. Therefore, this study aimed to analyze post-diagnosis spousal testing behaviors and its determinants in newly diagnosed people living with HIV (PLWH). Furthermore, among couples where both partners were infected, we aimed to identify factors associated with intra-household transmission that likely occurred prior to the index diagnosis. This nationwide, retrospective study investigated first spousal HCT (testing of the index case’s partner) and HIV transmission among newly diagnosed index PLWH from January 2011 to December 2020. The participants were classified into early and delayed spousal HCT groups based on time from diagnosis to first spousal HCT. The CD4+ T-cell count (CD4) depletion model was used to estimate the infection date, and factors associated with HIV transmission before diagnosis were analysed. Among eligible PLWH (n = 356,297), 50.4% had early spousal HCT, and 49.6% had delayed spousal HCT. Factors associated with delayed spousal HCT included older age (≥ 35 years: AOR = 1.06), certain ethnicities, occupation, infection route, and diagnosis setting. Pre-diagnosis transmission odds were higher in individuals aged > 35 years (AOR = 1.38), women (AOR = 2.19), individuals of other ethnicities than Han, and those engaged in sexual activity without condoms prior to diagnosis. Early detection and safe sexual practices should be promoted, with a particular focus on the populations identified in this study. Focusing on women, individuals aged > 35 years, and ethnic minority populations during testing is crucial. After an HIV-positive diagnosis, spousal testing and protective measures are essential to prevent HIV transmission among couples.