Kaposi sarcoma‐associated herpesvirus, HIV‐1 and Kaposi sarcoma risk in black South Africans diagnosed with cancer during antiretroviral treatment rollout

Kaposi sarcoma‐associated herpesvirus (KSHV) causes Kaposi sarcoma (KS). The risk of KS is amplified in HIV‐immunosuppressed individuals and antiretroviral therapy (ART) reduces KS incidence. Reliable data on the relationship between these factors are lacking in Africa. We used questionnaires and serum from 7886 black South Africans (18‐74 years) with incident cancer, recruited between 1995 and 2016. ART rollout started in 2004. We measured associations between KS, HIV‐1 and KSHV before and after ART rollout. We measured seropositivity to HIV‐1, KSHV latency‐associated nuclear antigen (LANA) and glycoprotein (K8.1) and calculated case‐control‐adjusted odds ratios (ORadj) and 95% confidence intervals (CI) in relation to KS and KSHV infection, before (1995‐2004), early (2005‐2009) and late (2010‐2016) ART rollout periods. KSHV seropositivity among 1237 KS cases was 98%. Among 6649 controls, KSHV seropositivity was higher in males (ORadj = 1.4 [95%CI 1.23‐1.52]), in persons with HIV, (ORadj = 4.2 [95%CI 3.74‐4.73]) and lower in high school leavers (ORadj = 0.7 [95%CI 0.59‐0.83]). KSHV seropositivity declined over the three ART rollout periods (37%, 28% and 28%, Ptrend