[Epidemiological characteristics of newly reported HIV-infected cases aged 50 years and above in Henan province,...

Objective: To analyze the epidemiological characteristics of newly reported HIV-infected cases aged 50 years and above in Henan province during 1995-2020, and to provide evidence for strategies on HIV/AIDS prevention and control. Methods: Information about newly reported HIV-infected cases aged 50 years and above in Henan between 1995 and 2020 were collected from the National Comprehensive HIV/AIDS Information System. The demographic and behavioral characteristics of HIV-infected cases aged ≥50 were analyzed, and the mixed linear model based on CD4⁺ T lymphocyte (CD4) counts back calculation was used to estimate the years, time and age of the HIV infection. Results: During 1995-2020, a total of 25 038 HIV-infected cases aged 50 years and above were newly reported, accounting for 25.8% (25 038/96 867) of the total number of newly reported HIV-infected cases in Henan. The proportion of newly reported cases over 50-years-old gradually increased from 4.5% (18/396) in 1995-2000 to 35.5% (9 666/27 239) in 2016-2020, with statistically significant difference (χ²=3 105.53, P<0.001). Among them, the proportion of HIV-infected cases aged 60 years and above were increasing year by year. The proportion of male cases were increasing along with ageing. The proportion of HIV-infected cases detected by medical institutions also showed an upward trend. The newly reported HIV-infected cases aged 50 years and above were mainly transmitted through sexual contact. The proportion of heterosexual transmission increased from 5.5% (1/18) in 1995-2000 to 86.2% (8 334/9 666) in 2016-2020, and the proportion of MSM-behavior-related transmission increased from 0.0% in 1995-2000 to 13.5% (1 304/9 666) in 2016-2020. The majority of cases had extra-marital and/or non-commercial heterosexual behavior (48.1%, 4 007/8 334) and the proportion showed an upward trend. The majority of male cases had commercial heterosexual behavior (54.9%, 3 169/5 775), and with increasing proportion along with the increase of age. The majority of female cases had extra-marital and/or non-commercial heterosexual behavior (62.5%, 1 600/2 559), with increasing proportion of extra-marital and/or non-commercial heterosexual behavior. The proportion of heterosexual behavior with spouse or stable sexual partners showed a downward trend. The estimations based on CD4 counts back calculation model showed that among the newly reported HIV-infected cases aged 50 years and above, the average age being infected was (54.8±10.2) years, with 33.8% (4 263/12 621) infected before 50. The interval between infection and diagnosis was (5.7±6.2) years, of which 52.6% (6 636/12 621) were infected for 5 years or longer and 34.7% (4 384/12 621) were in the last 3 years. There was no linear correlation trend in the composition of infection years among the newly reported HIV-infected cases over 50-years-old. Conclusions: In Henan, from 1995 to 2020, the number of newly reported HIV-infected cases aged 50 years and above was increasing and sexual transmission becoming the main transmission route. The increase of prevalence was mostly seen in 60-years-old men, low education level and detected mainly by medical institutions. For this age group, the focus of HIV/AIDS prevention and control should target on those who were transmitted through extra-marital and/or non-commercial heterosexual, commercial heterosexual and MSM behavior and it is necessary to strengthen the HIV testing and detection in this population and in the elderly floating group.