Risky sexual networks and concentrated HIV epidemics among men who have sex with men in Wenzhou, China: a respondent-driven sampling study.

BACKGROUND: The high and continually increasing prevalence of human immunodeficiency virus (HIV) and other sexually transmitted diseases among men who have sex with men (MSM) in China underscores the critical importance of examining the exact sexual networks that result in HIV transmission, as well as HIV infection, using powerful sampling methods, such as respondent-driven sampling (RDS), to improve the sexual health of this population. METHODS: Using RDS, a cross-sectional study was conducted among MSM in Wenzhou, Zhejiang province, China from December 2013 to June 2014. The type of sex, numbers of anal sex partners, male oral sex partners and vaginal sex partners, condom use during each type of sex over the previous 6 months, prevention behaviors, risk perception, and the burdens of HIV and syphilis were investigated and analyzed. RESULTS: Of 424 MSM, a great number of them did anal sex, male oral sex, and vaginal sex during the previous 6 months, and weighted estimates for the prevalence that MSM did not conduct these sexual behaviors were 11.2 % (95 % confidence interval [CI] =6.7-16.50 %), 20.3 % (95 % CI = 15.2-27.1 %), and 58.9 % (95 % CI = 52.1-65.8 %), respectively. Multiple sexual partners, engaging in regular, casual and commercial sex, and lack of condom use during all types of sex were common among MSM. The estimated HIV and syphilis prevalences were 22.8 % (95 % CI = 16.9-28.5 %) and 9.7 % (95 % CI = 6.4-13.6 %), respectively. Of the participants, 53.5 % (95 % CI = 45.3-60.2 %) received HIV-related interventions during the previous year, 48.1 % (95 % CI = 39.7-55.1 %) had never been tested for HIV, and only 14.1 % (95 % CI =10.1-19.2 %) perceived a risk of contracting HIV. Multiple logistic regression analysis revealed that age over 44 years (adjusted odds ratio [AOR] = 3.60, 95 % CI = 1.34-9.64), a monthly income of 3001-4000 yuan (approximately 470-630 US$) (AOR = 1.96, 95 % CI = 1.67-3.60), multiple anal sex partners (AOR = 1.93, 95 % CI = 1.15-3.24), awareness of the possibility of contracting HIV (AOR = 3.18, 95 % CI = 1.56-6.48), and current syphilis infection (AOR = 3.01, 95 % CI = 1.44-6.29) were predictors of HIV infection. CONCLUSIONS: HIV transmission has become highly prevalent and will likely become more prevalent among MSM and their female partners if these risky sexual networks persist. Our findings call for urgent and effective interventions to prevent the rapid transmission of HIV among MSM in Wenzhou.

Travel-associated outbreak of COVID-19 in a departmental store, Wenzhou, China.

INTRODUCTION: A local outbreak of coronavirus disease 2019 (COVID-19) has rapidly evolved into a global pandemic and the number of cases and deaths has increased exponentially. In this study, we report a COVID-19 outbreak that occurred in a departmental store, between January and February 2020, in Wenzhou, China and investigated the reasons for the outbreak. METHODOLOGY: An outbreak investigation was initiated after the index case was diagnosed as COVID-19. Cases (confirmed and suspected) and close contacts were defined. Their pharyngeal swabs were collected and examined with real-time polymerase chain reaction (RT-PCR) for nucleic acid. All investigations of the confirmed and suspected cases were carried out by epidemiologists and the source of infection was tracked by using big data. RESULTS: Thirty-nine COVID-19 cases and one asymptomatic individual were found in this outbreak, as determined by clinical manifestations, epidemiological investigation, and RT-PCR. Majority of COVID-19 cases occurred in a departmental store, three of whom traveled to participate in a meeting held in H city. After disease outbreak in the departmental store, intra-family transmission of COVID-19 occurred in five families. Two clusters of the COVID-19 outbreak were identified. One cluster was attributed to the family party, while another was attributed to a hotel party, which was responsible for transmission across three generations, infecting five family members. CONCLUSIONS: This was travel associated COVID-19 outbreak in a departmental store in Wenzhou, China. High infectivity of COVID-19 was observed. A departmental store, especially without recirculation of the air, was a high-risk site for the transmission of COVID-19. The use of big data and related information was very useful in epidemiological investigation of cases and contacts.