Background: A major obstacle to successful coronavirus disease (COVID-19) vaccine rollout is vaccine hesitancy. Acceptance of and preferences for COVID-19 vaccination among healthcare workers (HCWs) is critical, because they are a key target group for vaccination programs, and they are also highly influential to vaccine uptake in the wider population. This study sought to comparatively determine the acceptance of and preference for COVID-19 vaccination among HCWs and the general population. Methods: An Internet-based, region-stratified discrete-choice experiment was conducted among 352 HCWs and 189 general population respondents recruited in March 2020 from 26 Chinese provinces. We accessed knowledge of disease, attitude towards and acceptance of COVID-19 vaccination. Several attributes (related to COVID-19 disease, COVID-19 vaccination and one social acceptance) were identified as key determinants of vaccine acceptance. Results: HCWs had a more in-depth understanding of COVID-19 and showed a higher willingness to accept COVID-19 vaccines with lower effectiveness and/or more severe adverse effects compared to the general population. 76.4% of HCWs (vs 72.5% of the general population) expressed willingness to receive vaccination (χ ² =2.904, p =0.234). High levels of willingness to accept influenza (65.3%) and pneumococcal (55.7%) vaccination were also seen in HCWs. Future COVID-19 disease incidence (OR: 4.367, 95% CI 3.721–5.126), decisions about vaccination among social contacts of respondents (OR 0.398, 95% CI 0.339–0.467), and infection risk >30% (OR 2.706, 95% CI 1.776–2.425) significantly increased the probability of vaccination acceptance in HCWs. Conclusion: Multi-component interventions to address the key determinants of hesitancy in both HCWs and in the general population should be considered for COVID-19 vaccination programs.

Background: The attenuated live varicella vaccine had been shown to be effective in preventing varicella and reducing the disease burden in the United States. However, little work has been done on investigating vaccine effectiveness in China where 3 varicella vaccines are available. Although the vaccines contain the same strain of virus, the vaccines licensed in China were from manufacturers different from the one licensed in the United States. We conducted a matched case–control study to assess the effectiveness of the 3 varicella vaccines in use in China. Methods: In 2005, we enrolled 1000 cases from Guangzhou, China and 1000 controls matched by age and place of residence. The cases were children clinically diagnosed with acute onset of a diffuse maculopapulovesicular rash without other apparent cause. We interviewed the legal guardians of the participants for demographic information and disease history after obtaining informed consent. We collected information on vaccination status from electronic vaccination records. Results: The 3 varicella vaccines in China (Varilrix from GlaxoSmithKline, Changchun and Shanghai from Changchun and Shanghai Institutes of Biologic Products, respectively) had similar effectiveness: Varilrix 86.4% (95% confidence interval [CI]: 72.6, 93.2), Changchun 79.5% (95% CI: 58.1, 90.0), and Shanghai 92.6% (95% CI: 68.9, 98.2). Vaccine effectiveness was higher during the first year after vaccination than during the subsequent 5 years, but the differences did not reach statistical significance. Conclusions: The varicella vaccines in China are highly effective in preventing clinical varicella. Further studies on laboratory-confirmed cases are needed to verify the change of vaccine-induced immunity over time.

Data on the association between air pollution and risk of ischemic stroke in China are still limited. This study aimed to investigate the association between short-term exposure to ambient air pollution and risk of ischemic strokes in Guangzhou, the most densely-populated city in south China, using a large-scale multicenter database of stroke hospital admissions. Daily counts of ischemic stroke admissions over the study years 2013–2015 were obtained from the Guangzhou Cardiovascular and Cerebrovascular Disease Event Surveillance System. Daily particulate matter <2.5 μm in diameter (PM_2.5), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃), and meteorological data were collected. The associations between air pollutants and hospital admissions for stroke were examined using relative risks (RRs) and their corresponding 95% confidence intervals (CIs) based on time-series Poisson regression models, adjusting for temperature, public holiday, day of week, and temporal trends in stroke. Ischemic stroke admissions increased from 27,532 to 35,279 through 2013 to 2015, increasing by 28.14%. Parameter estimates for NO₂ exposure were robust regardless of the model used. The association between same-day NO₂ (RR = 1.0509, 95% CI: 1.0353–1.0668) exposure and stroke risk was significant when accounting for other air pollutants, day of the week, public holidays, temperature, and temporal trends in stroke events. Overall, we observed a borderline significant association between NO₂ exposure modeled as an averaged lag effect and ischemic stroke risk. This study provides data on air pollution exposures and stroke risk, and contributes to better planning of clinical services and emergency contingency response for stroke.

Background: The re-emergence of dengue virus 4 (DENV-4) has become a public health concern in South America, Southeast Asia and South Asia. However, it has not been known to have caused a local outbreak in China for the past 20 years. The purpose of this study was to elucidate the epidemiology of one local community outbreak caused by DENV-4 in Guangzhou city, China, in 2010; and to determine the molecular characteristics of the genotype II virus involved. Case presentations: During September and October of 2010, one imported case, a Guangzhou resident who travelled back from Thailand, resulted in 18 secondary autochthonous cases in Guangzhou City, with an incidence rate of 5.53 per 10,000 residents. In indigenous cases, 14 serum samples tested positive for IgM against DENV and 7 for IgG from a total of 15 submitted serum samples, accompanied by 5 DENV-4 isolates. With identical envelope gene nucleotide sequences, the two isolates (D10168-GZ from the imported index case and Guangzhou 10660 from the first isolate in the autochthonous cases) were grouped into DENV-4 genotype II after comparison to 32 previous DENV-4 isolates from GenBank that originated from different areas. Conclusions: Based on epidemiological and phylogenetic analyses, the outbreak, which was absent for 20 years after the DENV-4 genotype I outbreak in 1990, was confirmed as DENV-4 genotype II and initially traced to the imported index case, a Guangzhou resident who travelled back from Thailand.