Background: Hepatitis B virus (HBV) infection is a major public health problem in China. Over a decade has passed since the last National Hepatitis Seroepidemiological Survey was conducted in 2006. The lack of updated data on hepatitis B in China makes assessing the current prevalence and burden of the disease inadequate. In response to the above situation, a systematic review and meta-analysis was conducted to provide a better understanding of hepatitis B epidemiology in the general population of China. Methods: A systematic search was conducted in international databases (Medline through PubMed, EMBASE, Cochrane, Web of Science) and national databases (CBM, CNKI, WanFang Data) to retrieve primary studies published between January 1, 2013 and December 31, 2017. The pooled prevalence of HBV infection and 95% confidence intervals were calculated. Quality assessment, heterogeneity testing and publication bias assessment were also performed. Results: Of the 27 studies included in the meta-analysis, the pooled estimated prevalence of HBV infection in the general population of China from 2013 to 2017 was 6.89% (95% CI:5.84–7.95%), which could be extrapolated to an estimated population of 84 million living with HBsAg in 2018. The prevalence of HBV infection in males was higher than that in females (5.88% vs 5.05%), and rural areas had a higher prevalence than urban areas (5.86% vs 3.29%). The highest prevalence of HBV infection was reported in Western provinces (8.92, 95% CI: 7.19–10.64%). In adults older than 20 years, the prevalence of HBV infection was approximately 7%, which was higher than that in children. Conclusion: The prevalence of HBV infection in the general population of China was classified as higher intermediate prevalence (5–7.99%), of which more than 90% of the HBV infection population included adults older than 20 years. The blocking of mother-to-infant hepatitis B transmission and plans involving timely birth dose of hepatitis B vaccine within 24 h should be implemented. Additionally, improving the quality of life and survival rate of the infected population through antiviral therapy and high-risk adult vaccination will be the priority of our future work. Moreover, various control measures should be implemented in different provinces across China.

The prevalence of metabolic-associated fatty liver disease (MAFLD) is rarely reported in Beijing. The goal of this study was to estimate the prevalence and risk factors of MAFLD among Beijing adults aged ≥25 years old. A cross-sectional, community-based survey with multistage stratified cluster sampling was used. Demographic, transient elastography (TE), biochemical and blood examination information was collected in all the subjects in this study. The prevalence of MAFLD was 32.40% (23,832/73,566). Risk factors independently associated with MAFLD included male gender (OR = 1.47, 95%CI, 1.43–1.52), urban residence (OR = 1.06, 95% CI, 1.02–1.10), older age (30–39 years: OR = 1.29; 40–49 years: OR = 1.43; 50–59 years: OR = 1.09; ≥60 years: OR = 1.52) and lower education (middle school: OR = 2.03; high school: OR = 1.89; undergraduate: OR = 1.69). MAFLD was more common in females than in males after 50 years of age. Lean/normal weight MAFLD patients account for approximately 3.04% (724/23,832) of MAFLD. Compared to non-MAFLD subjects, the lean/normal MAFLD patients had a higher prevalence of hypertension and diabetes, and had a higher degree of hepatic steatosis and liver function enzymology parameters (all p < 0.001). MAFLD was highly prevalent among the general population aged ≥25 years old in Beijing. MAFLD was closely associated with male gender, older age, lower education and urban residence. Even lean/normal-weight people were under risk of MAFLD.

Many encapsulated bacteria use capsules to cause invasive diseases. However, it remains largely unknown how the capsules enhance bacterial virulence under in vivo infection conditions. Here we show that the capsules primarily target the liver to enhance bacterial survival at the onset of blood-borne infections. In a mouse sepsis model, the capsules enabled human pathogens Streptococcus pneumoniae and Escherichia coli to circumvent the recognition of liver-resident macrophage Kupffer cells (KCs) in a capsular serotype-dependent manner. In contrast to effective capture of acapsular bacteria by KCs, the encapsulated bacteria are partially (low-virulence types) or completely (high-virulence types) “untouchable” for KCs. We finally identified the asialoglycoprotein receptor (ASGR) as the first known capsule receptor on KCs to recognize the low-virulence serotype-7F and -14 pneumococcal capsules. Our data identify the molecular interplay between the capsules and KCs as a master controller of the fate and virulence of encapsulated bacteria, and suggest that the interplay is targetable for therapeutic control of septic infections.

CoronaVac is an inactivated vaccine containing whole-virion SARS-CoV-2, which has been approved in 43 countries for emergency use as of 26 November 2021. However, the long-term immune persistence of the CoronaVac vaccine is still unknown. Here, we reported the status of the persistence of antibodies and cellular responses within 12 months after two doses of CoronaVac. Such data are crucial to inform ongoing and future vaccination strategies to combat COVID-19.

Neutralizing antibody is an important indicator of vaccine efficacy, of which IgG is the main component. IgG can be divided into four subclasses. Up to now, studies analysing the humoral response to SARS‐CoV‐2 vaccination have mostly focused on measuring total IgG, and the contribution of specific IgG subclasses remains elusive. The aim of this study is to investigate the kinetics of neutralizing antibodies and IgG subclasses, and to explore their relationships in people vaccinated with inactivated COVID‐19 vaccine. We conducted a prospective cohort study in 174 healthy adults aged 18–59 years old who were administrated 2 doses of CoronaVac 14 days apart and a booster dose 1 year after the primary immunization, and followed up for 15 months. Blood samples were collected at various time points after primary and booster immunization. We used live SARS‐CoV‐2 virus neutralizing assay to determine neutralizing ability against the wild‐type strain and 4 variants (Beta, Gamma, Delta and Omicron) and ELISA to quantify SARS‐CoV‐2 RBD‐specific IgG subclasses. The results showed that the 2‐dose primary immunization only achieved low neutralizing ability, while a booster shot can significantly enhance neutralizing ability against the wild‐type strain, Beta, Gamma, Delta and Omicron variants. IgG1 and IgG3 were the most abundant serum antibodies, and IgG2 and IgG4 were hardly detected at any time. The ratio of IgG1/IgG3 was positively associated with the neutralization ability. The underlying mechanism requires further exploration.

Backgroud: Beijing was hyper-endemic for hepatitis A until the 1990s and has been vaccinating against hepatitis A since 1994. The objective is to study the epidemiology and changes of antibody level of hepatitis A from 1990 to 2017. Methods: A multistage randomized cluster sampling serological cross-sectional study was conducted in individuals over one year old in 1992, 2006 and 2014 in Beijing. Venous blood samples were collected to test anti-HAV antibody. The incidence data of hepatitis A were obtained from National Notifiable Disease Reporting System (NNDRS) and CDC statistics in Beijing. The vaccination data of hepatitis A immunization were acquired from Beijing Immune Information System. Results: From 1990 to 2017, the reported incidence rate of HAV in Beijing declined from 59.41/100,000 in 1990 to 0.80/100,000 in 2017. The average age of HAV infection was postponed from individuals under 20 years old to individuals over 20 years old. After hepatitis A vaccine was introduced to Beijing, the outbreak of hepatitis A decreased sharply. Adjusted anti-HAV positive rate in general population was 68.23%, 81.73% and 82.47% respectively in 1992, 2006 and 2014. Due to hepatitis A vaccination conducted in children, the anti-HAV positive rate in individuals under 20 years old increased from 1992 to 2014, while in individuals over 20, this rate was barely changed. The coverage rate in target population was higher than 99% after hepatitis A vaccine was integrated into Expanded Program on Immunization (EPI). Conclusion: Incidence rate of hepatitis A in Beijing has decreased dramatically from 1990 to 2017. Hepatitis A vaccine plays an important role in protecting individuals under 20 years old. A higher proportion of adults will be susceptible to hepatitis A virus due to the decay of antibodies as they grow up from childhood to adulthood, which may result in possible outbreak of hepatitis A.