A Case Report of HIV Transmission Within a Household Involving a Married Man Who Has Sex with Men in China

Background: Married Men who have Sex with Men (MSM) constitute a bridge population for HIV diffusion into low-risk groups, with spousal non-disclosure rates exceeding 60% in China. It will increase the risk of secondary transmission within families. Despite the timely implementation of evidence-based interventions, reducing MTCT rates to below 2% in China, residual pediatric infections persist. Case Report: In 2025, a man in Jinan City, Shandong Province, was diagnosed with HIV infection likely acquired through sexual contact with men and may have subsequently transmitted the virus to his breastfeeding spouse via heterosexual intercourse. The mother, in turn, likely transmitted HIV to her infant through breastfeeding, resulting in an intrafamilial transmission cluster involving three individuals. All three family members are currently receiving standard antiretroviral therapy (ART) for HIV management. Conclusion: Married MSM may bridge HIV to spouses, necessitating supported partner notification services. "To mitigate false-negative results from maternal HIV antibody tests during pregnancy, a pre-delivery Nucleic Acid Test (NAT) is imperative. Sustained postpartum screening prevents tertiary transmission in breastfeeding families.