# The changing molecular epidemiology of HIV-1 in Liangshan prefecture, China, in 2021–2023

## TL;DR

This study analyzed the changing HIV-1 genetic variants in Liangshan, China, from 2021 to 2023, finding a decline in CRF07_BC and rise in other variants.

## Contribution

The study provides the first detailed molecular epidemiology analysis of HIV-1 in Liangshan Prefecture in recent years.

## Key findings

- CRF07_BC was the dominant HIV-1 variant but decreased over the study period.
- Other HIV-1 variants, such as CRF08_BC and CRF01_AE, increased in prevalence.
- Newly diagnosed patients showed a higher proportion of non-CRF07_BC variants compared to treatment failure patients.

## Abstract

Liangshan Prefecture is one of the areas in China most severely affected by human immunodeficiency virus (HIV), but little is known about the molecular epidemiology of HIV-1 in this area. We aimed to analyze the distribution of HIV-1 genetic variants in Liangshan Prefecture in recent years.

8,523 blood samples were collected from people living with HIV with treatment failure and newly diagnosed individuals in all 17 counties and cities in Liangshan Prefecture between 2021 and 2023.

The majority of study participants were male (66%), farmers (78%) and illiterate (53%). The main HIV-1 transmission routes were heterosexual contact (57%) and injecting drug use (27%). Among the 6,298 successfully obtained pol sequences the following HIV-1 variants were identified: CRF07_BC (93.9%), CRF08_BC (3.3%), CRF01_AE (1.4%), URFs (0.9%), CRF105_0108 (0.1%), CRF55_01B (0.1%), subtype B (0.1%), subtype C (0.1%), CRF88_BC (0.1%), CRF83_cpx (0.1%), CRF85_BC (0.03%), CRF67_01B (0.02%), CRF77_cpx (0.02%), and subtype A (0.02%). During the study period, the proportion of CRF07_BC gradually decreased, while other HIV-1 variants increased, a shift seen across all counties in Liangshan Prefecture. Newly diagnosed patients mainly acquired HIV through heterosexual transmission (86.7%), had a lower proportion of CRF07_BC (90.9%) and higher proportion of other HIV-1 variants, compared to treatment failure patients.

Future prevention and control policies need to take these changes into account.