Lin Chen

Background: In the postpandemic era, trends in HIV, syphilis, and hepatitis C virus (HCV) infections, as well as the prevalence of coinfections among high-risk groups, may have shifted; however, relevant empirical studies are limited. Objective: This study aimed to assess the seropositivity rates and coinfection rates for HIV, syphilis, and anti-HCV; and to explore the correlates of HIV, syphilis, and anti-HCV positivity among voluntary counseling and testing (VCT) clients at Centers for Disease Control and Prevention (CDC)–affiliated clinics in Zhejiang Province from 2022 to 2024. Methods: This retrospective study analyzed routine data extracted in January 2025 from the National HIV Information Prevention and Control System. The Cochran-Armitage trend chi-square test was used to analyze trends in positivity rates over the years. Logistic regression was used to identify relevant indicators for positivity for HIV, syphilis, and anti-HCV in 2024. Results: The HIV positivity rates decreased from 2.462% (743/30,182) in 2022 to 1.664% (681/40,916) in 2024 (χ21 for trend =53.6; P<.001). The syphilis positivity rates were 1.378% (414/30,049), 1.502% (675/44,951), and 1.62% (647/39,929) in 2022, 2023, and 2024, respectively (χ21 for trend=6.8; P=.03). The anti-HCV positivity rates were 0.309% (77/24,950), 0.387% (161/41,593), and 0.504% (192/38,098) in 2022, 2023, and 2024, respectively (χ21 for trend=14.8; P<.001). In 2024, the positivity rates for dual HIV–anti-HCV coinfection, dual HIV-syphilis coinfection, and triple HIV-syphilis–anti-HCV coinfection were 0.011%, 0.203%, and 0.005%, respectively. Multivariable logistic regression analysis showed that age ≥35 years and HIV testing history were associated with HIV, syphilis, and anti-HCV positivity; compared with proactive consultation, outreach consultation was associated with lower odds of HIV positivity (adjusted odds ratio [aOR] 0.096, 95% CI 0.060-0.153), but higher odds of syphilis positivity (aOR 1.241, 95% CI 1.033-1.491) and anti-HCV positivity (aOR 2.837, 95% CI 1.882-4.276); compared with consulting for casual heterosexual behavior, consulting for homosexual behavior was associated with higher odds of HIV positivity (aOR 1.909, 95% CI 1.514-2.408) and lower odds of anti-HCV positivity (aOR 0.031, 95% CI 0.011-0.082). Conclusions: From 2022 to 2024 in Zhejiang Province, the HIV and anti-HCV positivity rates among VCT clients at CDC-affiliated clinics declined, while the syphilis positivity rates increased. The coinfection positivity rates for these 3 infections remained at low levels. Individuals reporting homosexual behavior constituted a high-risk group for HIV positivity yet exhibited a lower positivity rate for anti-HCV. Among CDC-affiliated VCT clients, older age, lower educational attainment, and prior HIV testing history were associated with higher infection positivity rates, suggesting that these characteristics might help refine targeting of VCT and prevention efforts within this setting.

Background: Pretreatment drug resistance (PDR) poses an increasing threat to the effectiveness of antiretroviral therapy and treatment-as-prevention strategies. Zhejiang Province, an economically developed region in eastern China with high population mobility, experiences complex HIV-1 subtype dynamics and evolving resistance patterns. However, recent population-based evidence integrating HIV genetic subtypes, PDR prevalence, and associated factors remains limited. Objective: This study aimed to characterize HIV-1 subtype distribution, estimate the prevalence of PDR, and identify associated demographic, virological, and prophylaxis-related factors among newly diagnosed individuals in Zhejiang Province from 2022 to 2024. Methods: We conducted a cross-sectional study among adults newly diagnosed with HIV-1 in Zhejiang Province between 2022 and 2024. Demographic, epidemiological, laboratory, and exposure prophylaxis information was collected through the provincial HIV surveillance system. Partial Pol gene sequences were amplified and sequenced to determine HIV subtypes and drug resistance mutations. PDR was interpreted using the Stanford University HIV Drug Resistance Database. Logistic regression models were applied to identify factors associated with PDR. Results: Among 8798 newly diagnosed individuals, the predominant subtypes were CRF07_BC (n=3913, 44.5%), CRF01_AE (n=2524, 28.7%), and CRF08_BC (n=954, 10.8%), with significant heterogeneity across age groups, sexes, transmission routes, and diagnosis years ( P <.001). Overall PDR prevalence was 5.7% (n=504), with resistance mainly to nonnucleoside reverse-transcriptase inhibitors (n=352, 4.0%). The most frequently detected mutations were K103N, M184V, and M46L. Multivariable analysis showed that higher baseline CD4 cell counts, diagnosis in 2023 and 2024, and infection with the CRF01_AE subtype were independently associated with increased odds of PDR. Pre-exposure prophylaxis was not associated with overall PDR; however, drug-specific analyses demonstrated significant associations between exposure prophylaxis and pretreatment resistance to emtricitabine ( P <.001) and lamivudine ( P <.001). Conclusions: HIV-1 genetic diversity in Zhejiang Province remains complex and dynamic, accompanied by an increasing prevalence of PDR. Although exposure prophylaxis was not linked to overall PDR, its association with emtricitabine-specific resistance highlighted the need for strengthened HIV-1 testing prior to prophylaxis initiation and enhanced resistance surveillance, but they require confirmation in future studies.

BACKGROUND In the postpandemic era, trends in HIV, syphilis, and hepatitis C virus (HCV) infections, as well as the prevalence of coinfections among high-risk groups, may have shifted; however, relevant empirical studies are limited. OBJECTIVE This study aimed to assess the seropositivity rates and coinfection rates for HIV, syphilis, and anti-HCV; and to explore the correlates of HIV, syphilis, and anti-HCV positivity among voluntary counseling and testing (VCT) clients at Centers for Disease Control and Prevention (CDC)–affiliated clinics in Zhejiang Province from 2022 to 2024. METHODS This retrospective study analyzed routine data extracted in January 2025 from the National HIV Information Prevention and Control System. The Cochran-Armitage trend chi-square test was used to analyze trends in positivity rates over the years. Logistic regression was used to identify relevant indicators for positivity for HIV, syphilis, and anti-HCV in 2024. RESULTS The HIV positivity rates decreased from 2.462% (743/30,182) in 2022 to 1.664% (681/40,916) in 2024 (χ21 for trend =53.6; P<.001). The syphilis positivity rates were 1.378% (414/30,049), 1.502% (675/44,951), and 1.62% (647/39,929) in 2022, 2023, and 2024, respectively (χ21 for trend=6.8; P=.03). The anti-HCV positivity rates were 0.309% (77/24,950), 0.387% (161/41,593), and 0.504% (192/38,098) in 2022, 2023, and 2024, respectively (χ21 for trend=14.8; P<.001). In 2024, the positivity rates for dual HIV–anti-HCV coinfection, dual HIV-syphilis coinfection, and triple HIV-syphilis–anti-HCV coinfection were 0.011%, 0.203%, and 0.005%, respectively. Multivariable logistic regression analysis showed that age ≥35 years and HIV testing history were associated with HIV, syphilis, and anti-HCV positivity; compared with proactive consultation, outreach consultation was associated with lower odds of HIV positivity (adjusted odds ratio [aOR] 0.096, 95% CI 0.060-0.153), but higher odds of syphilis positivity (aOR 1.241, 95% CI 1.033-1.491) and anti-HCV positivity (aOR 2.837, 95% CI 1.882-4.276); compared with consulting for casual heterosexual behavior, consulting for homosexual behavior was associated with higher odds of HIV positivity (aOR 1.909, 95% CI 1.514-2.408) and lower odds of anti-HCV positivity (aOR 0.031, 95% CI 0.011-0.082). CONCLUSIONS From 2022 to 2024 in Zhejiang Province, the HIV and anti-HCV positivity rates among VCT clients at CDC-affiliated clinics declined, while the syphilis positivity rates increased. The coinfection positivity rates for these 3 infections remained at low levels. Individuals reporting homosexual behavior constituted a high-risk group for HIV positivity yet exhibited a lower positivity rate for anti-HCV. Among CDC-affiliated VCT clients, older age, lower educational attainment, and prior HIV testing history were associated with higher infection positivity rates, suggesting that these characteristics might help refine targeting of VCT and prevention efforts within this setting.

Background: With the growing popularity and convenience of the internet, an increasing number of men who have sex with men (MSM) are seeking casual sexual partners online. However, the effect of online casual sexual behavior on other HIV-related risk behaviors remains unclear. Objective: This study aims to explore the characteristics of internet-based casual sexual behavior and its relationship with HIV-related risk behaviors among MSM. Methods: This cross-sectional study was conducted between June and December 2018 in 4 cities in Zhejiang Province, China. Peer-driven sampling was used for recruitment. Announcements were disseminated by 4 community-based organizations and 10 voluntary counseling and testing clinics online and offline. After informed consent, participants completed an electronic questionnaire covering demographic characteristics, casual sexual behaviors, HIV-related risk behaviors, and HIV prevention. SPSS (version 19.0; IBM Corp) was used to conduct chi-square tests, univariate and multivariate logistic regression analyses using a backward stepwise method based on the likelihood ratio test, and Poisson regression with robust variance to identify associations between finding casual sexual partners online and other risk behaviors. P values of <.05 were considered statistically significant. Results: In the past 6 months, 40.2% (302/751) of participants reported finding casual sexual partners online; 18.9% (142/751) reported finding casual sexual partners offline; 7.6% (57/751) reported having sexual intercourse with MSM without condoms after drinking alcohol; and 6.9% (52/751) reported condomless sex after using stimulants. Among those who found partners online, 62.5% (188/301) did so more than once per month and 39.5% (113/286) had more than one online sexual partner. In total, 39.3% (114/290) had sex with online partners at home and 10.1% (30/297) sought partners in other cities. Compared with participants who engaged in receptive anal intercourse (or both roles), those who engaged only in insertive intercourse reported a higher proportion of finding partners online more than once per month (72.7% vs 57.4%, P=.01), having more than 2 online sexual partners (52.1% vs 33.3%, P=.002), and conducting inconsistent condom use with online sexual partners (40.0% vs 25.8%, P=.01). Regression analysis showed that, compared with MSM who did not find partners online, those who did were more likely to report finding casual sexual partners offline (adjusted odds ratio [aOR] 9.398; 95% CI 5.956‐14.829), having sex without condoms after drinking alcohol (adjusted prevalence ratio [aPR] 1.788; 95% CI 1.062‐3.011), and having sexual intercourse without condoms after using stimulants (aPR 2.064; 95% CI 1.178‐3.617). Conclusions: Internet-based casual sexual behavior is increasingly common among MSM. Finding partners online was associated with offline partner-seeking and condomless use after alcohol or stimulant use. Future HIV prevention efforts should emphasize behavioral interventions tailored to MSM who use dating apps.

This study was conducted to explore the human immunodeficiency virus (HIV) status of and compare HIV knowledge, HIV testing, and other healthy behaviors between men who have sex with men and women (MSMW) and men who have sex with men only (MSMO), to provide a scientific basis for targeted HIV interventions for this population. A cross-sectional survey was conducted to collect demographic and behavioral information using questionnaires for statistical analysis. Among 1,993 participants, 772 (38.7%) reported having sexual intercourse with women. The results of the multivariate logistic regression model analysis indicated that MSMW had a lower probability than MSMO of reporting HIV knowledge 1 (adjusted odds ratio [aOR]:0.556, 95% CI: 0.409–0.756), knowledge 2 (aOR:0.626; 95% CI, 0.515–0.761), knowledge 3 (aOR:0.569; 95% CI: 0.447–0.724), informing their HIV status to the last casual sex partners offline (aOR: 0.515, 95% CI: 0.358–0.743), HIV testing more than once in the past 6 months (aOR: 0.696, 95% CI: 0.521–0.931), and HIV testing in a hospital in the past 6 months (aOR: 0.696, 95% CI: 0.521–0.931). In contrast, MSMW had a higher probability of post-exposure prophylaxis (PEP) intake in the past 6 months (aOR: 2.252, 95% CI: 1.570–3.229), pre-exposure prophylaxis (PrEP) intake in the past 6 months (aOR: 1.630, 95% CI: 1.091–2.434), and cumulative HIV testing more than twice (aOR: 1.917, 95% CI: 1.434–2.563). MSMW showed significant differences with MSMO in HIV knowledge and HIV related risky reduction behaviors. It is necessary to enhance awareness and skills on HIV self-testing, PEP, and PrEP among MSM. Encouraging HIV knowledge education and HIV testing service are important for MSMW. PEP and PrEP might be enhanced among MSMO for reducing the risk of HIV transmission.

Background: Men who have sex with men (MSM) are increasingly using the internet to meet casual sexual partners. Those who do are at higher risk of sexually transmitted diseases. However, little is known about the rates and associations of frequent HIV testing and self-testing among such MSM. Objective: We aimed to examine HIV serostatus communication and perceptions regarding the HIV infection risk of internet-based partners, along with their associations with frequent HIV testing and self-testing. Methods: A cross-sectional study was conducted between May 2018 and April 2019 in Zhejiang Province, China. The study participants were assigned male at birth, were aged 18 years or older, had had casual sex with another male found through the internet in the last 6 months, and were HIV-negative. Information was obtained on HIV-testing behavior, along with demographic characteristics, HIV-related knowledge, internet-based behaviors, sexual behaviors with male partners, HIV serostatus communication, and perceptions regarding the HIV infection risk of internet-based partners. Uni- and multivariate logistic regression models were used to measure the associations of HIV testing and self-testing. Results: The study recruited 281 individuals who had sought casual sexual partners through the internet during the previous 6 months. Of the participants, 61.9% (174/281) reported frequent HIV testing (twice or more frequently) and 50.9% (119/234; 47 with missing values) reported frequent HIV self-testing. MSM who always or usually communicated about the HIV serostatus of internet-based partners in the previous 6 months had 3.12 (95% CI 1.76-5.52) and 2.45 (95% CI 1.42-4.22) times higher odds of being frequently tested or self-tested for HIV, respectively, compared with those who communicated about this issue minimally or not at all. Conclusions: There remains a need to improve the frequency of HIV testing and self-testing among internet-based MSM. HIV serostatus communication should be improved within the context of social networking applications to promote frequent HIV testing among internet-based MSM, especially for those who communicated about this issue minimally or not at all.

To identify differences in human immunodeficiency virus (HIV) risky behavior and healthy practices between rural and urban men who have sex with men (MSM) in Southeast China, a cross-sectional study was conducted on MSM aged ≥ 18 years recruited from four community-based organizations (CBOs) in seven cities in Zhejiang Province between October 2022 and March 2023. An electronic survey questionnaire was completed by the study participants to collect HIV risky behavior and healthy practices. The chi-square test and multiple logistic regression were used for analysis. Among the 1,993 MSM participants, 21.1% (420) were rural MSM. Compared with urban MSM, rural MSM was more likely to have a low level of education (high school and below; 46.2% vs. 40.2%, p = 0.028) and a low annual income (≤ 90,000 RMB; 71.2% vs. 64.7%, p = 0.013). Multiple logistic regression showed that, compared with urban MSM in the past 6 months behaviors, rural MSM had lower odds of finding casual sex partners on the Internet (adjusted odds ratio [aOR]: 0.790, 95% confidence interval [CI]: 0.633–0.986), using stimulants with online casual sex partners (aOR: 0.688, 95% CI: 0.506–0.936), and high odds of ever having sex with a female (aOR: 1.460, 95% CI:1.036–2.058). Rural MSM reported lower odds of an HIV knowledge score of 2–3 (aOR: 0.586, 95% CI: 0.454–0.756), HIV testing more than twice (aOR: 0.583, 95% CI: 0.455–0.748), and obtaining four to five types of HIV information (aOR: 0.661, 95% CI: 0.529–0.826), as well as higher odds of high/very high awareness of HIV infection risk (aOR: 2.312, 95% CI: 1.638–3.263), compared to urban MSM. Rural MSM and urban MSM reported discrepancies in HIV risky behavior, HIV knowledge and HIV-related healthy practices. Paying more attention to HIV risky behavior and improving healthy practices in rural areas may help to prevent HIV transmission.

Background: HIV notification and testing integrated into partner service (PS) practices among HIV-positive individuals have been proven to be an efficient approach for case finding, although it remains a weak link in China. Although nonmarital sexual activities accounted for a large proportion of newly diagnosed HIV-positive cases in China, little is known about PS uptake and associated factors within nonmarital partnerships. Objective: This study aimed to describe HIV PS utilization and its associated factors among HIV-positive individuals with nonmarital sexual partners. Methods: We recruited newly diagnosed HIV-positive individuals who had nonmarital sexual partners in 2022 in Zhejiang Province and offered them PS. We described the PS uptake cascade within sexual partner categories and analyzed the associated factors with 3 primary outcomes from the participants’ perspective: nonmarital partner enumeration, HIV testing, and HIV positivity. Results: In this study, 3509 HIV-positive individuals were recruited as participants, and they enumerated 2507 nonmarital sex partners (2507/14,556, 17.2% of all nonmarital sex partners) with contact information. Among these, 43.1% (1090/2507) underwent an HIV test, with an HIV-positive rate of 28.3% (309/1090). Heterosexual commercial partners were the least likely of being enumerated (441/4292, 10.3%) and had the highest HIV-positive rate (40/107, 37.4%). At the participant level, 48.1% (1688/3509) of the participants enumerated at least one nonmarital sex partner with contact information, 52.7% (890/1688) had a sex partner tested for HIV, and 31% (276/890) had at least one nonmarital sex partner who tested positive. Multivariate analysis indicated that gender and transmission route were associated with both nonmarital sex partner enumeration and HIV testing. Age and occupation were associated with nonmarital sex partner enumeration and HIV positivity. Compared with participants who had no regular nonmarital sex partner, those who had a regular nonmarital sex partner were more likely to enumerate nonmarital sex partners (adjusted odds ratio [aOR] 3.017, 95% CI 2.560-3.554), have them get tested for HIV (aOR 1.725, 95% CI 1.403-2.122), and have an HIV-positive nonmarital sex partner (aOR 1.962, 95% CI 1.454-2.647). Conclusions: The percentage of partner enumeration was low, and HIV testing rate was moderate among nonmarital partnerships of HIV-positive individuals. More efforts should be made to improve PS practices among HIV-positive individuals and address the gap in partner enumeration, especially for heterosexual commercial nonmarital partnerships. Additionally, enhancing PS operational skills among health care personnel could increase the overall efficiency of PS uptake in China.