Results from recent trials assessing the effect of vitamin D supplementation on the prevention of childhood acute respiratory infections (ARI) have been inconsistent. In the present study, we determined whether vitamin D supplementation prevents ARI in healthy children and repeated infections in children with previous ARI. We conducted a systematic literature search using MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials. The search included only randomised controlled clinical trials (RCT) comparing vitamin D supplementation with either placebo or no intervention in children younger than 18 years of age. We identified seven RCT and found that the summary estimates were not statistically significantly associated with a reduction in the risk of ARI (relative risk (RR) 0·79, 95 % CI 0·55, 1·13), all-cause mortality (RR 1·18, 95 % CI 0·71, 1·94), or the rate of hospital admission due to respiratory infection in healthy children (RR 0·95, 95 % CI 0·72, 1·26). However, in children previously diagnosed with asthma, vitamin D supplementation resulted in a 74 % reduction in the risk of asthma exacerbation (RR 0·26, 95 % CI 0·11, 0·59; test of heterogeneity, I²= 0·0 %). Our findings indicate a lack of evidence supporting the routine use of vitamin D supplementation for the prevention of ARI in healthy children; however, they suggest that such supplementation may benefit children previously diagnosed with asthma. Due to the heterogeneity of the included studies and possible publication biases related to this field, these results should be interpreted with caution.

Men who have sex with men (MSM) are a high risk population for human immunodeficiency virus (HIV) infection. Our study aims to find whether MSM who were recruited online had a higher prevalence of self-reported unprotected anal intercourse (UAI) than those who were recruited offline.

The aim of this study was to investigate the prevalence of high-risky behaviors, such as unprotected anal intercourse (UAI) in the last 6 months, condom using in their last homosexual anal intercourse, No. of male partners in the last 6 months among high school and college male students who have sex with men (MSM) in China. The relevant trials were retrieved up to June 2015 from several public databases, and a meta-analysis was conducted according to the published studies. The estimated rate and its 95 % confidence intervals (CI) of the relevant indexes among high school and college student MSM were collected and calculated using a fixed-effects model (the Mantel-Haenszel method) or a random-effects model (the DerSimonian and Laird method) when appropriate. A total of 15 studies (18 research data), including 3297 student MSM, were performed in this meta-analysis. The overall results showed that the rate of student MSM who reported having had UAI in the last 6 months was 65.2 % (95 % CI = 60.2 % to 70.1 %), the prevalence of student MSM having more than one male partner in the last 6 months was 58.2 % (95 % CI = 51.1 % to 65.4 %), the rate of student MSM who reported using a condom in their last homosexual anal intercourse experience was 57.5 % (95 % CI = 49.8 % to 65.1 %), the prevalence of student MSM who were infected with HIV was 3.8 % (95 % CI = 2.5 % to 5.1 %), and the rate of student MSM who were infected with syphilis was 4.6 % (95 % CI = 3.8 % to 5.4 %). There are high UAI prevalence and low condom using rate in the last homosexual anal intercourse experience among high school and college student MSM in China, and corresponding control measures for this group and more effective health education of student MSM are required to prevent HIV or sexually transmitted diseases from spreading to the general population.

Objective: The purpose of this study was to explore the situations and factors influencing casual sexual behavior among male college students, in order to provide scientific evidences and measures of the prevention and control for HIV/AIDS. Method: Using the stratified cluster sampling method, male college students who self-reported sexual behavior were selected as survey subjects in 13 colleges and universities in 11 cities of Zhejiang Province from October to November 2018. We used a custom online questionnaire to collect information on the demographic characteristics, sexual attitudes, sexual behaviors, and HIV interventions of the respondents. The χ² test was performed on the composition ratios between different groups. With the occurrence of casual sexual behavior as the dependent variable, logistic regression was used to analyze the factors influencing casual male sexual behavior. Results: A total of 2734 male college students were surveyed, aged 20.20±1.41 years, of which 595 had casual sex, accounting for 21.7%. The rate of HIV prevention awareness among the participants was 85.1%. Multivariate analysis showed that receiving a self-assessment of HIV risk conducted by the school (Ajusted OR = 1.45, 95% CI = 1.14–1.84), knowing that HIV self-test kits were available at school (Ajusted OR = 2.02, 95% CI = 1.56–2.62), accepting one-night stands (Ajusted OR = 2.82, 95% CI = 2.18–3.66), accepting commercial sex (Ajusted OR = 1.95, 95% CI = 1.53–2.48), being a man who has sex with men (Ajusted OR = 1.81, 95% CI = 1.37–2.39), being a senior (Ajusted OR = 0.46, 95% CI = 0.30–0.71), having knowledge of HIV/AIDS prevention and treatment (Ajusted OR = 0.66, 95% CI = 0.51–0.86), and knowing that the CDC provides HIV testing services (Ajusted OR = 0.56, 95% CI = 0.41–0.77) were factors influencing male college students’ casual sexual behavior. Conclusion: Male college students who have causal sexual behaviors have a high degree of openness in sexual attitudes, insufficient knowledge of AIDS prevention, and knowledge of HIV testing-related information but low testing rates. For male college students’ HIV prevention education intervention, it is necessary to emphasize the establishment of correct sexual attitudes and concepts and promote safe sexual behaviors to prevent the spread of HIV.

Background: There is growing evidence that men who have sex with men (MSM) are currently a group at high risk of HIV infection in China. Our study aims to know the factors affecting consistent condom use among MSM recruited through the internet in Huzhou city. Methods: An anonymous cross-sectional study was conducted by recruiting 410 MSM living in Huzhou city via the Internet. The socio-demographic profiles (age, education level, employment status, etc.) and sexual risk behaviors of the respondents were investigated. Bivariate logistic regression analyses were performed to compare the differences between consistent condom users and inconsistent condom users. Variables with significant bivariate between groups’ differences were used as candidate variables in a stepwise multivariate logistic regression model. All statistical analyses were performed using SPSS for Windows 17.0, and a p value < 0.05 was considered to be statistically significant. Results: According to their condom use, sixty-eight respondents were classified into two groups. One is consistent condom users, and the other is inconsistent condom users. Multivariate logistic regression showed that respondents who had a comprehensive knowledge of HIV (OR = 4.08, 95% CI: 1.85-8.99), who had sex with male sex workers (OR = 15.30, 95% CI: 5.89-39.75) and who had not drunk alcohol before sex (OR = 3.10, 95% CI: 1.38-6.95) were more likely to be consistent condom users. Conclusions: Consistent condom use among MSM was associated with comprehensive knowledge of HIV and a lack of alcohol use before sexual contact. As a result, reducing alcohol consumption and enhancing education regarding the risks of HIV among sexually active MSM would be effective in preventing of HIV transmission.

Recently, a novel H7N9 avian influenza A virus has led to a human influenza outbreak in China. Here we report a 64-year old man with possible history of chronic bronchitis died from the H7N9 infection in Huzhou City, Zhejiang Province in Eastern China. The patient had been exposed to poultry before disease onset. Phylogenetic analyses of hemagglutinin and neuraminidase genes showed a close genetic relationship between viruses from the patient and from poultry booths where he had visited, indicating that the patient may have been exposed from the infected poultry. Two poultry venders and close contacts of the patient were negative for H7N9, suggesting that there are some unknown mechanisms to prevent them from being infected by the novel H7N9 virus. Furthermore, we found five novel H7N9 virus-specific sequence variations in receptor-binding site of hemagglutinin, which may be associated with the acquisition of the ability to infect humans.