Objective: To understand the vaccination of varicella attenuated live vaccine (VarV) among students in collective institutions, to provide a basis for analying the protective effect of vaccination. Methods: All collective institutions with chickenpox epidemic and post exposure vaccination in Jing an District from 2017 to 2019 were investigated. All students( n =6 473) in the affected class were included. Vaccination status and the incidence information of disease were collected to analyze vaccine effectiveness (VE). Results: The proportion of study subjects without an immunization history decreased year by year, and 7.5% in 2017, 7.2 % in 2018, and 4.9% in 2019. The proportion with a history of one dose prior to exposure in cases was 90.0%, it was lower than 93.5% in the non cases ( χ 2=6.53, P <0.05). The proportion with one dose as post exposure prophylaxis in cases was 8.3%, it was much lower than 44.1% in the non cases ( χ 2=179.06, P <0.01). The proportion with one dose as post exposure prophylaxis in secondary cases was 28.6%, much lower than 44.1% in the non cases ( χ 2=9.44, P <0.01).Unvaccinated ones and the second dose as post exposure prophylaxis ones in cases had the highest rate of varicella development (11.0%), a history of one dose prior to exposure and one dose as post exposure prophylaxis in cases had the lowest varicella rate (1.0%).There was a clear protective effect within two years after one dose of VarV inoculation, VE was 63.1%(95% CI =11.0%-84.7%). Conclusion The vaccine effectiveness of one dose VarV was limited. Post exposure prophylaxis as early as possible was highly effective in decreasing secondary attack rate.

ObjectiveTo analyze the epidemiological characteristics and the vaccination status of the cases in Jing’an District from 2017 to 2019， so as to provide reference basis for the strategy of prevention and control of varicella epidemic. MethodsDescriptive epidemiological methods were used to analyze the epidemiological characteristics of varicella in Jing’an District. The differences between the vaccinated group and the unvaccinated group were compared by statistical methods. ResultsA total of 2 508 cases of varicella were reported with an average annual incidence of 78.7/10⁵ from 2017 to 2019. There was no significant difference in the incidence among the three years（χ²=5.535，P=0.063）. There were 1 308 males and 1 200 females， and sex ratio was 1.1∶1. The highest incidence occurred in the age group from 5 to 9 years old （562 cases， 479.3/10⁵）. Two annual peaks occured in May and November. The incidence in the aged 18 and below decreased year by year. There was significant difference in the proportion among the three years（χ²=78.129， P<0.001）. The median interval from vaccination to onset was 5 years among the vaccinated cases. There was significant difference in the cases who received two doses of vaccine in three years（χ²=90.902， P<0.001）. ConclusionWe should strengthen the monitoring system and pay more attention to the epidemiological characteristics of varicella. The protective efficacy of two-doses vaccine needs to be systematically evaluated.

Objective:To analyze the effectiveness and immunogenicity of enterovirus-A71(EV-A71) vaccine in immunization program.Methods:A cohort study was conducted in immunization clinics in Jing’an district in Shanghai from October to December 2017. Children who received EV-A71 vaccine based on a 2-dose schedule (on day 0 and day 30) were enrolled as vaccine group and those who received no EV-A71 vaccine were enrolled as control group. After 1-year follow-up, the effectiveness and neutralizing antibody level and the positive results of antibody immunogenicity in vaccine group were analyzed.Results:A total of 3 018 children aged 8-20 months were enrolled, in whom 1 211 were in vaccine group and 1 807 were in control group. The vaccine effectiveness was 100% against EV-A71-associated hand, foot, and mouth disease (HFMD) indicated by 1 year follow-up (95 %CI: -66.99%-100.00%). The geometric mean titer of neutralizing antibody (GMT) was 41.76 (95 %CI: 35.60-49.34) at day 60 and 28.44(95 %CI: 23.59-34.54) at day 365 in 124 children in vaccine group. Conclusions:In children, EV-A71 vaccine elicited EV-A71-specific immune response. Less EV-A71-associated HFMD cases have been observed, further observation is needed.

ObjectiveTo understand the surveillance of influenza-like illness (ILI) and influenza vaccination status in Jing’an District, Shanghai, and to provide a basis for optimizing influenza prevention and control strategies. MethodsThe sentinel surveillance data for ILI and virological surveillance data of influenza viruses in Jing’an District were collected from the Chinese influenza surveillance information system, and data for influenza vaccination were collected from Shanghai immunization information system from September 2017 to August 2023. Epidemiological characteristics of ILI, influenza etiology, and the temporal and population distributions of influenza vaccination were analyzed using descriptive epidemiological methods. ResultsILI as a percentage of total visit surveillance units (ILI%) reported by sentinel hospital was increased in Jing’an District of Shanghai from September 2017 to August 2023 (F=18.841, P=0.012). The peak of the influenza cases mainly appeared in winter-spring, but there were two peaks in winter-spring and summer from September 2019 to August 2020, from September 2020 to August 2021, and from September 2021 to August 2022. In particular, there were two peaks in winter-spring from September 2022 to August 2023, with a rebound during the descending process. The average positive rate of ILI was 21.64% (2 421/11 189) during the 6 years. There was a peak in winter-spring during every year with the exception of the period from September 2020 to August 2021. The dominant strains were B/Yamagata and A/H1N1 in winter-spring from September 2017 to August 2018. The dominant strain was A/H1N1 in winter-spring from September 2018 to August 2019 and from September 2022 to August 2023. The dominant strain was B/Victoria in winter-spring from September 2019 to August 2020 and from September 2021 to August 2022. Different subtype strains occurred alternately, and the dominant strains were A/H1N1 and A/H3N2 in recent years. The influenza vaccination coverage was 2.94% from September 2017 to August 2023, and the vaccination coverage was highest in young children. The vaccination coverage for females was higher than that for males (χ²=546.963, P<0.001), and the vaccination coverage for registered residents was higher compared to that for migrants (χ²=123.141, P<0.001). ConclusionILI% exhibits an upward trend in Jing’an District of Shanghai, and the dominant strain is A subtype. The influenza vaccination coverage is still low, which is insufficient to have an impact on the spread of influenza. It is recommended that the surveillance of ILI and variations of influenza virus strains should be improved continuously, and effective steps should be taken to promote influenza vaccination.