Preplanned Studies: Epidemiological Characteristics of Newly-Reported HIV Cases Among Youth Aged 15−24 Years — China, 2010−2019

The estimated number of people living with human immunodeficiency virus (HIV) has grown to 38 million globally by the end of 2019. About 1,400 new HIV infections occur every day (1-2) among the group aged 15–24 years, which the United Nations (UN) defines as ‘youths’ (3). Youths face a higher risk of HIV infection due to their increased sexual activity and related risky behaviors (4). In China, all new diagnoses of HIV infections are required to be reported to the HIV/AIDS Comprehensive Response Information Management System (CRIMS). This study described the epidemiological characteristics of newly reported HIV cases among the 15–24 age group between 2010 and 2019. The data were extracted from CRIMS on December 31, 2019. Newly reported HIV cases from the 15–24 age group during 2010–2019 were selected from the mainland of China. HIV case records include demographic characteristics, area of reporting, route of HIV infection, diagnosis site, etc. The spatial distribution was described in terms of reporting areas and provincial-level administrative divisions (PLADs). A total of 141,557 HIV cases from the 15–24 age group were reported from 2010 to 2019 in China. The annual numbers showed an upward trend between 2010 and 2015 and remained stable from 2016 to 2019 with a male-to-female ratio at 4.07∶1, and the route of HIV infection was mainly homosexual transmission among men who have sex with men (MSM). The results show that between 2010 and 2019, the number of HIV diagnoses among youth aged 15–24 in 2010 and 2019 were 9,373 and 15,790, respectively, with an average annual increase of 6.0%. The average annual increase was 10.0% for males (Table 1).

An estimated 80.3% of reported HIV cases were males. The male-to-female ratio was 4.07∶1, and there was an increasing trend year over year. Over the past decade starting 2010, the average age for the overall population, males, and females were 22.2±3.34 years, 22.2±3.29 years, and 22.1±3.51 years, respectively. An estimated 78.9% of reported cases were in the 20–24 age group. The proportions of reported cases aged 15–19 increased from 15.7% in 2010 to 24% in 2019, while decreasing from 84.3% in 2010 to 76% in 2019 for those aged 20–24. The reported cases over the past decade were mainly of Han ethnicity (79.4%). The proportion of students among reported cases increased from 8.5% in 2010 to 21.7% in 2019. Over the past decade starting from 2010, Sichuan Province accounted for the highest number over the study period. There were increases in the proportions of reported cases in eastern (Shanghai, Zhejiang, Jiangsu, Anhui, Jiangxi, Fujian, and Shandong) and central (Henan, Hubei, Hunan) China, while decreases were found in southwestern [Chongqing, Sichuan, Guizhou, Yunnan, Xizang (Tibet)] China, which was the region that comprised the highest proportion in 2019. Males diagnosed with HIV were mainly distributed in southwestern, eastern, and central China, and the top 5 PLADs with the highest number of reported cases in 2019 were Sichuan, Guangdong, Hunan, Jiangsu, and Henan. Females were mainly distributed in southwestern, northwestern (Shaanxi, Gansu, Qinghai, Xinjiang, Ningxia), and southern (Guangdong, Guangxi, Hainan) China, and the top 5 PLADs with the highest number of reported cases in 2019 were Sichuan, Yunnan, Xinjiang, Guangdong, and Guizhou (Table1).

Among newly reported HIV cases between 2010 and 2019 among youth aged 15–24 years, the proportions of blood or plasma transfusion and injection drug use transmission decreased annually. Sexual transmission was the main route of HIV infection and the proportion of homosexual contact transmission showed an upward trend in 2010–2015 and remained stable after that (Table 1). Homosexual transmission was the main route of HIV infection among males, and heterosexual transmission was the main route of HIV infection among females (Table 2).