Background: Varicella is a mild, self-limited disease caused by varicella-zoster virus (VZV) infection. Recently, the disease burden of varicella has been gradually increasing in China; however, the epidemiological characteristics of varicella have not been reported for Anhui Province. Objective: The aim of this study was to analyze the epidemiology of varicella in Anhui from 2012 to 2021, which can provide a basis for the future study and formulation of varicella prevention and control policies in the province. Methods: Surveillance data were used to characterize the epidemiology of varicella in Anhui from 2012 to 2021 in terms of population, time, and space. Spatial autocorrelation of varicella was explored using the Moran index (Moran I). The Kulldorff space-time scan statistic was used to analyze the spatiotemporal aggregation of varicella. Results: A total of 276,115 cases of varicella were reported from 2012 to 2021 in Anhui, with an average annual incidence of 44.8 per 100,000, and the highest incidence was 81.2 per 100,000 in 2019. The male-to-female ratio of cases was approximately 1.26, which has been gradually decreasing in recent years. The population aged 5-14 years comprised the high-incidence group, although the incidence in the population 30 years and older has gradually increased. Students accounted for the majority of cases, and the proportion of cases in both home-reared children (aged 0-7 years who are not sent to nurseries, daycare centers, or school) and kindergarten children (aged 3-6 years) has changed slightly in recent years. There were two peaks of varicella incidence annually, except for 2020, and the incidence was typically higher in the winter peak than in summer. The incidence of varicella in southern Anhui was higher than that in northern Anhui. The average annual incidence at the county level ranged from 6.61 to 152.14 per 100,000, and the varicella epidemics in 2018-2021 were relatively severe. The spatial and temporal distribution of varicella in Anhui was not random, with a positive spatial autocorrelation found at the county level (Moran I=0.412). There were 11 districts or counties with high-high clusters, mainly distributed in the south of Anhui, and 3 districts or counties with high-low or low-high clusters. Space-time scan analysis identified five possible clusters of areas, and the most likely cluster was distributed in the southeastern region of Anhui. Conclusions: This study comprehensively describes the epidemiology and changing trend of varicella in Anhui from 2012 to 2021. In the future, preventive and control measures should be strengthened for the key populations and regions of varicella.

The Omicron EG.5 lineage of SARS-CoV-2 is currently on a trajectory to become the dominant strain. This phase 2 study aims to evaluate the immunogenicity of SCTV01E-2, a tetravalent protein vaccine, with a specific emphasis on its immunogenicity against Omicron EG.5, comparing it with its progenitor vaccine, SCTV01E (NCT05933512). As of 12 September 2023, 429 participants aged ≥18 years were randomized into the groups SCTV01E (N = 215) and SCTV01E-2 (N = 214). Both vaccines showed increases in neutralizing antibody (nAb) against Omicron EG.5, with a 5.7-fold increase and a 9.0-fold increase in the SCTV01E and SCTV01E-2 groups 14 days post-vaccination, respectively. The predetermined statistical endpoints were achieved, showing that the geometric mean titer (GMT) of nAb and the seroresponse rate (SRR) against Omicron EG.5 were significantly higher in the SCTV01E-2 group than in the SCTV01E group. Additionally, SCTV01E and SCTV01E-2 induced a 5.5-fold and a 5.9-fold increase in nAb against XBB.1, respectively. Reactogenicity was generally mild and transient. No vaccine-related serious adverse events (SAEs), adverse events of special interest (AESIs), or deaths were reported. In summary, SCTV01E-2 elicited robust neutralizing responses against Omicron EG.5 and XBB.1 without raising safety concerns, highlighting its potential as a versatile COVID-19 vaccine against SARS-CoV-2 variants.

The Omicron EG.5 lineage of SARS-CoV-2 is currently on a trajectory to become a dominant strain. This phase 2 study aims to evaluate the immunogenicity of SCTV01E-2, a tetravalent protein vaccine, with a specific emphasis on its effectiveness against Omicron EG.5, comparing it with its progenitor vaccine, SCTV01E (NCT05933512). As of September 12, 2023, 429 participants aged ≥18 years were randomized to SCTV01E (N=215) or SCTV01E-2 (N=214) groups. Both vaccines showed increases in neutralizing antibody (nAb) against Omicron EG.5, with a 5.7-fold increase and a 9.0-fold increase in SCTV01E and SCTV01E-2 groups 14 days post-vaccination, respectively. The predetermined statistical endpoints were achieved, showing that the geometric mean titer (GMT) of nAb and the seroresponse rate (SRR) against Omicron EG.5 were significantly higher in the SCTV01E-2 group compared to SCTV01E. Additionally, SCTV01E and SCTV01E-2 induced a 5.5-fold and a 5.9-fold increase of nAb against XBB.1, respectively. Reactogenicity was generally mild and transient. No vaccine related SAEs, AESIs or deaths were reported. In summary, SCTV01E-2 elicited robust neutralizing responses against Omicron EG.5 and XBB.1 without safety concerns, underlining its potential as a versatile COVID-19 vaccine against SARS-CoV-2 variants.

Many studies have investigated the positivity rate of hepatitis B surface antibody (HBsAb) after hepatitis B vaccine (HepB) immunization. However, the antibody level, assessed monthly or at more frequent intervals after each of the three doses, particularly within the first year after birth, has not been previously reported. To elucidate the level of antibody formation at various times after vaccination, the current study used the available detection data of HBsAb in hospitalized children to analyze the HBsAb level after immunization combined with their vaccination history. Both the positivity rate and geometric mean concentration (GMC) increased sequentially with immunization doses, reaching their peaks earlier after the third dose than after the first two doses, and the rate of HBsAb positivity was able to reach 100% between 11 and 90 days after completing the three doses of HepB. Within one year after receiving the three doses, the antibody positivity rate and GMC were maintained above 90% and 100 mIU/mL, respectively, and subsequently steadily declined, reaching the lowest value in the 9th and 10th years. The current findings reveal, in more detail, the level of antibody formation at different times following each dose of HepB in hospitalized children, particularly in the age group up to one year after vaccination. For the subjects of this study, we prefer to believe that the proportion of HBsAb non-response should be less than 5% after full immunization with HepB, provided that the appropriate time for blood collection is chosen.

Background/Objectives: Sabin strain-based inactivated poliovirus vaccine (sIPV) is increasingly used in China’s routine immunization program and is often administered concomitantly with other childhood vaccines. However, large-scale real-world evidence on the safety of concomitant sIPV vaccination remains limited. This study evaluated the safety of sIPV administered standalone or concomitantly with other routine vaccines using provincial surveillance data. Methods: A retrospective observational study was conducted using data from the China National Adverse Events Following Immunization Surveillance System and the Anhui Provincial Immunization Information Management System. All sIPV doses administered between 1 November 2023 and 31 July 2025 were included. AEFI reporting rates per 100,000 doses were calculated. Descriptive analyses were performed by demographic characteristics and dose number. Multivariable negative binomial regression models were used to assess the association between vaccination mode and AEFI incidence, with dose-stratified analyses when appropriate. Results: Among the 303,526 sIPV doses analyzed (135,550 standalone and 167,976 concomitant), 188 AEFI cases were reported, yielding an overall reporting rate of 61.94 per 100,000 doses. Most AEFI were mild, self-limited general reactions, mainly fever and local injection-site reactions. Only two serious AEFI were reported, both resolving without sequelae. After adjustment for confounders, no significant difference in overall AEFI incidence was observed between standalone and concomitant vaccination (aRR = 0.97, 95% CI: 0.64–1.47). AEFI reporting was associated with age and region, while no consistent dose-related trend was identified. Conclusions: sIPV showed a favorable safety profile when administered standalone or concomitantly with other routine vaccines in real-world settings. Concomitant vaccination did not increase AEFI risk, supporting the continued use of sIPV in routine immunization programs.

Following the emergence of COVID-19, breakthrough SARS-CoV-2 infections have demonstrated substantial heterogeneity in both occurrence and clinical severity. This case–control study aimed to elucidate the factors associated with the incidence, duration, and severity of SARS-CoV-2 symptoms among Chinese adults during the Omicron wave. The analysis was based on data from a national COVID-19 surveillance program encompassing six provinces—Jiangsu, Chongqing, Shandong, Hunan, Anhui, and Yunnan—and included both laboratory-confirmed and clinically diagnosed cases. Data were systematically collected between February and April 2023. For each confirmed case, a matched control was selected through simple random sampling, matched on sex, age (±5 years), and province of residence. Multivariate logistic regression analyses were employed to assess a range of potential determinants, including demographic characteristics, lifestyle behaviors, and pre-existing medical conditions, in relation to the risk of infection, as well as the persistence and severity of symptoms following SARS-CoV-2 breakthrough infection. A total of 10,426 cases and 10,426 matched controls were included in the final analysis. Among the infected individuals, 963 (9.24%) reported persistent symptoms, while 773 (7.41%) experienced moderate-to-severe clinical manifestations. Occasional alcohol consumption, presence of comorbidities, tea and coffee intake, overweight status, and a longer interval since the last vaccination dose were all significantly associated with increased odds of infection (OR > 1, FDR < 0.05). Conversely, weekly alcohol consumption and smoking were associated with a decreased risk (OR < 1, FDR < 0.05). Female sex was significantly associated with both persistent and moderate-to-severe symptoms. Additional risk factors for prolonged or severe symptoms included older age, being underweight or overweight, a history of immunotherapy, coffee consumption, and the presence of comorbidities. These findings underscore the multifactorial nature of SARS-CoV-2 infection outcomes and highlight the interplay between host characteristics and behavioral factors. The results support the development of personalized prevention strategies aimed at reducing the clinical burden and long-term impact of COVID-19.