[Characteristics and influencing factors of newly HIV infection among newly confirmed HIV/AIDS cases in Ningbo city, 2017-2020].

Objective: To identify the characteristics and influencing factors of local HIV infection among newly confirmed cases in Ningbo from 2017 to 2020 to provide evidence for traceability investigations on critical cases and facilitate the detection procedures and reduce new HIV infection. Methods: From January 1, 2017, to December 31, 2020, the newly confirmed HIV/AIDS in Ningbo were recruited. An epidemiological questionnaire was used to collect relevant information, including demography, sexual behaviors, results of HIV antibody tests, and the route of HIV transmission. According to the HIV testing, history of risk behaviors, and the level of CD4+ lymphocytes after confirmation, the HIV infection was acquired in the previous year, or the place was in Ningbo. The EpiData 3.1 and SPSS 23.0 software were used for input, sorting database and statistical analysis. Results: A total of 2 044 HIV/AIDS on-site investigations were completed. The average age of the subjects was (40.6±15.3) years old, including 1 684 males (82.4%), 758 unmarrieds (37.1%), 1 072 (52.5%) registered as permanent residents in Ningbo, 1 253 (61.3%) with junior high school education or below, 979 (47.9%) lived in Ningbo for more than five years. The proportion of local, new HIV infections was 34.34% (702/2 044). Multivariate logistic analysis showed that the proportion of local newly HIV infection was higher among those who were confirmed in 2020 (compared with the 2017 confirmed cases, OR=1.422, 95%CI:1.092-1.851), whose occupations were students/teachers/cadres/retirees (compared to commercial service/catering/public place service personnel, OR=1.682, 95%CI: 1.307-2.165), meeting sex partners via male social software locally in the last year (compared with without using related dating software, OR=1.353, 95%CI: 1.073-1.706). Conclusions: The proportion of local HIV infection of newly confirmed HIV/AIDS was relatively high in Ningbo city from 2017 to 2020. Meeting gay sex partners through local male social software appeared a risk factor for local newly HIV infection. Traceability investigations and internet intervention should be carried out for MSM. While male social software should be focused on identifying and controlling the risk of local newly HIV infection.