Geographic origins, transmission hotspots, and drug resistance mutations of HIV-1 CRF08_BC in Zhejiang Province, China.

PURPOSE

To understand the geographic origins, transmission hotspots, and drug resistance mutations (DRMs) of HIV-1 CRF08_BC in Zhejiang Province, China.

METHODS

This study analyzed HIV-1 CRF08_BC pol sequences collected between 2020 and 2023. Bayesian inference was employed to investigate temporal epidemic trends, while HIV-TRACE and MCODE were used to identify transmission clusters (TCs), key hotspots and super-spreaders. DRMs associated with CRF08_BC were also characterized. Additionally, demographic data were integrated with these findings, allowing for a description of the transmission dynamics.

RESULTS

This study revealed that CRF08_BC strains in Zhejiang likely originated from Guangxi, with significant transmission among individuals aged 50 and older, particularly those with low educational levels. Molecular transmission analysis showed that 58.9% of CRF08_BC sequences were in TCs, with geographic concentrations in Taizhou (TZ) and Lishui (LS). 14 large clusters maintained effective reproductive numbers (Re) above 1, representing considerable epidemic growth. Hangzhou (HZ) emerged as a key transmission hub, with 10 TCs showing active transmission. LS established strong epidemiological links with HZ, Ningbo (NB), Taizhou (TZ), and Wenzhou (WZ), creating a pattern of viral spread radiating from LS to surrounding areas. DRMs were identified in 76 cases (6.0%), with NNRTI and NRTI mutations exhibiting distinct geographic clustering.

CONCLUSIONS

The CRF08_BC strains in Zhejiang likely originated from Guangxi and are mainly found in individuals aged 50 and older with low education. The current epidemic hotspots are in TZ and LS, where NNRTI and NRTI mutations are clustered, significantly impacting treatment efficacy.