Characteristics of SARS-CoV-2 transmission in a medium-sized city with traditional communities during the early COVID-19 epidemic in China.

The nationwide COVID-19 epidemic ended in 2020, a few months after its outbreak in Wuhan, China at the end of 2019. Most COVID-19 cases occurred in Hubei Province, with a few local outbreaks in other provinces of China. A few studies have reported the early SARS-CoV-2 epidemics in several large cities or provinces of China. However, information regarding the early epidemics in small and medium-sized cities, where there are still traditionally large families and community culture is more strongly maintained and thus, transmission profiles may differ, is limited. In this study, we characterized 60 newly sequenced SARS-CoV-2 genomes from Anyang as a representative of small and medium-sized Chinese cities, compared them with more than 400 reference genomes from the early outbreak, and studied the SARS-CoV-2 transmission profiles. Genomic epidemiology revealed multiple SARS-CoV-2 introductions in Anyang and a large-scale expansion of the epidemic because of the large family size. Moreover, our study revealed two transmission patterns in a single outbreak, which were attributed to different social activities. We observed the complete dynamic process of single-nucleotide polymorphism development during community transmission and found that intrahost variant analysis was an effective approach to studying cluster infections. In summary, our study provided new SARS-CoV-2 transmission profiles representative of small and medium-sized Chinese cities as well as information on the evolution of SARS-CoV-2 strains during the early COVID-19 epidemic in China.

Body mass index and risk of gastric cancer: a meta-analysis.

OBJECTIVE: Overweight and obesity, indicated as increased body mass index, are associated with the risk of some cancers. We carried out a meta-analysis on published cohort and case-control studies to assess the strength of association between body mass index and gastric cancer. METHODS: Relevant studies were identified through PubMed, Web of Science and Medline electronic databases. Adjusted relative risks (odds ratios) with 95% confidence interval were used to assess the strength of association between body mass index and gastric cancer. RESULTS: Sixteen eligible studies were included in this meta-analysis. Overall, obesity (body mass index ≥ 30 kg/m(2)) was associated with an increased risk of gastric cancer (odds ratio = 1.13, 95% confidence interval = 1.03-1.24) compared with normal weight (body mass index = 18.5 to <25 kg/m(2)), while overweight (body mass index = 18.5 to <30 kg/m(2)) showed no association (odds ratio = 1.04, 95% confidence interval = 0.96-1.12). Specifically, a stratified analysis showed there were associations between obesity and the increased risk of gastric cancer for males (odds ratio = 1.27, 95% confidence interval = 1.09-1.48), non-Asians (odds ratio = 1.14, 95% confidence interval = 1.02-1.28) and both cohort studies (odds ratio = 1.10, 95% confidence interval = 1.00-1.22) and case-control studies (odds ratio = 1.29, 95% confidence interval = 1.03-1.60). Both overweight (odds ratio = 1.22, 95% confidence interval = 1.05-1.42) and obesity (odds ratio = 1.61, 95% confidence interval = 1.15-2.24) were associated with the increased risk of gastric cardia cancer. CONCLUSIONS: The results indicated that obesity was associated with the risk of gastric cancer, especially for males and among non-Asians. Both overweight and obesity were associated with the risk of gastric cardia cancer.

Safety of influenza A (H1N1) vaccine in postmarketing surveillance in China.

BACKGROUND: On September 21, 2009, China began administering vaccines, obtained from 10 different manufacturers, against 2009 pandemic influenza A (H1N1) virus infection in priority populations. We aimed to assess the safety of this vaccination program. METHODS: We designed a plan for passive surveillance for adverse events after immunization with the influenza A (H1N1) vaccine. Physicians or vaccination providers were required to report the numbers of vaccinees and all adverse events to their local Center for Disease Control and Prevention (CDC), which then reported the data to the Chinese CDC through the online National Immunization Information System's National Adverse Event Following Immunization Surveillance System. Data were collected through March 21, 2010, and were verified and analyzed by the Chinese CDC. RESULTS: A total of 89.6 million doses of vaccine were administered from September 21, 2009, through March 21, 2010, and 8067 vaccinees reported having an adverse event, for a rate of 90.0 per 1 million doses. The age-specific rates of adverse events ranged from 31.4 per 1 million doses among persons 60 years of age or older to 130.6 per 1 million doses among persons 9 years of age or younger, and the manufacturer-specific rates ranged from 4.6 to 185.4 per 1 million doses. A total of 6552 of the 8067 adverse events (81.2%; rate, 73.1 per 1 million doses) were verified as vaccine reactions; 1083 of the 8067 (13.4%; rate, 12.1 per 1 million doses) were rare and more serious (vs. common, minor events), most of which (1050) were allergic reactions. Eleven cases of the Guillain-Barré syndrome were reported, for a rate of 0.1 per 1 million doses, which is lower than the background rate in China. CONCLUSIONS: No pattern of adverse events that would be of concern was observed after the administration of influenza A (H1N1) vaccine, nor was there evidence of an increased risk of the Guillain-Barré syndrome.