Background: The Zhejiang Immunization Information System (ZJIIS) was established in 2004. This study described the coverage rates of NIP vaccines in Zhejiang Province using the ZJIIS. Methods: Children aged 1–7 years (born from 1 January 2005 to 31 December 2011) registered in ZJIIS were enrolled in this study. All immunization records were obtained from the ZJIIS on 31 December 2012. The cohort method had been used for identifying trends and patterns in vaccine administration. Immunization coverage estimates were analyzed for both individual NIP vaccines and “Fully immunized” by age group, birth cohort, immigration status, and geography area. We also examined the timeliness vaccination for the 2010 birth cohort. Results: A total of 3,579,896 children were registered in ZJIIS. All the vaccines and doses which scheduled to be given at ≤12 months of age exceeded 90%. There was substantial decrease trend in the vaccines scheduled at >12 months of age and most of these vaccines were below 90%. The coverage of migrant children was lower than for resident children and the coverage of WenZhou (WZ), Zhoushan (ZS) and TaiZhou (TZ) was lower than other municipalities for most of vaccines across all the birth cohorts. Nearly 20%–30% of children of 2010 birth cohort delayed for the primary series vaccination scheduled at ≤12 months of age, especially among migrant children. Conclusions: The ZJIIS is useful in tracking vaccine coverage of children aged 1–7 years and the data provided by ZJIIS reflected the fact that NIP delivery was improving in Zhejiang Province, while identifying some areas for improvement. We recommend continuing surveillance to estimate of vaccine coverage through ZJIIS. Immunization strategies such as Assessment, Feedback, Incentives, and Exchange program, reminder/recall activity, home visits, school entry requirements and school-based clinics could be used to reach a higher coverage of the population.

An EPI (Expanded Program on Immunization) intervention package was implemented from October 2011 to May 2014 among migrant children in Yiwu, east China. This study aimed to evaluate its impacts on vaccination coverage, maternal understanding of EPI and the local immunization service performance. A pre- and post-test design was used. The EPI intervention package included: (1) extending the EPI service time and increasing the frequency of vaccination service; (2) training program for vaccinators; (3) developing a screening tool to identify vaccination demands among migrant clinic attendants; (4) Social mobilization for immunization. Data were obtained from random sampling investigations, vaccination service statistics and qualitative interviews with vaccinators and mothers of migrant children. The analysis of quantitative data was based on a “before and after” evaluation and qualitative data were analyzed using content analysis. The immunization registration (records kept by immunization clinics) rate increased from 87.4 to 91.9 % (P = 0.016) after implementation of the EPI intervention package and the EPI card holding (EPI card kept by caregivers) rate increased from 90.9 to 95.6 % (P = 0.003). The coverage of fully immunized increased from 71.5 to 88.6 % for migrant children aged 1–4 years (P < 0.001) and increased from 42.2 to 80.5 % for migrant children aged 2–4 years (P < 0.001). The correct response rates on valid doses and management of adverse events among vaccinators were over 90 % after training. The correct response rates on immunization among mothers of migrant children were 86.8–99.3 % after interventions. Our study showed a substantial improvement in vaccination coverage among migrant children in Yiwu after implementation of the EPI intervention package. Further studies are needed to evaluate the cost-effectiveness of the interventions, to identify individual interventions that make the biggest contribution to coverage, and to examine the sustainability of the interventions within the existing vaccination service delivery system in a larger scale settings or in a longer term.

Following the rollout of a booster campaign to promote immunity against COVID-19 in China, this study aimed to assess booster hesitancy among adults who were fully vaccinated with primary doses across Zhejiang Province. Firstly, the modified 5C scale developed by a German research team was assessed for reliability and validity via a pre-survey in Zhejiang Province. Then, a 30-item questionnaire was established to conduct online and offline surveys during 10 November to 15 December 2021. Demographic characteristics and information on previous vaccination experience, vaccine type of primary doses, attitudes towards booster doses and awareness of SARS-CoV-2 infection were collected. Chi-square tests, pairwise comparison and multivariate logistic regression were performed in data analysis. In total, 4039 valid questionnaires were analyzed, with booster hesitancy of 14.81%. Dissatisfaction with previous vaccination experience of primary doses (ORs = 1.771~8.025), less confidence in COVID-19 vaccines (OR = 3.511, 95%CI: 2.874~4.310), younger age compared to the elderly aged 51–60 years old (2.382, 1.274~4.545), lower education level (ORs = 1.707~2.100), weaker awareness of social responsibility of prevention and control of COVID-19 (1.587, 1.353~1.859), inconvenience of booster vaccination (1.539, 1.302~1.821), complacency regarding vaccine efficacy as well as self-health status (1.224, 1.056~1.415) and excessive trade-offs before vaccination (1.184, 1.005~1.398) were positively associated with booster hesitancy. Therefore, intelligent means should be strengthened to optimize vaccination services. More influential experts and other significant figures should be supported to promote timely evidence-based information via various media platforms to reduce public hesitancy and increase booster uptake.

In order to control the spread of rubella and reduce the risk for congenital rubella syndrome, an additional rubella vaccination program was set up for all secondary school students since 2008 in Zhejiang, China. We conducted a descriptive analysis of rubella incidence among different age groups from 2005 to 2015 and a serosurvey of female subjects aged 15–39 years to understand the possible effects of this immunization program. The average annual rubella incidence rate had decreased from 15.86 per 100,000 population (2005–2007) to 0.75 per 100,000 population (2013–2015) in Zhejiang. The decrease in the rate of rubella incidence in girls aged 15–19 years was more accelerated (from 138.30 to 0.34 per 100,000) than in the total population during 2008–2015 (from 32.20 to 0.46 per 100,000). Of 1225 female subjects in the serosurvey, 256 (20.9%) were not immune to rubella. The proportion of subjects immune to rubella was significantly different among different age groups (Wald χ2 = 22.19, p = 0.000), and subjects aged 15–19 years old had the highest immunity (88.0%). Rubella antibody levels were significantly lower in women aged 25–30 years with 26.7% of them not immune, followed by the group aged 20–24 years (25.0%) and 30–35 years (24.5%). Rubella vaccine included in the Expanded Program on Immunization together with vaccination activities for secondary school students can help in rubella control, particularly in targeted age groups in the program. Seroprevalence of antibodies to the rubella virus amongst the female population within childbearing age in Zhejiang, China, is still too low to provide immunity. In addition to vaccination programs in the secondary schools, rubella vaccination should also be encouraged in women of childbearing age, which can be done effectively combined with pre-marital examination in China.

Background: Measles and rubella are vaccine-preventable diseases targeted for elimination in most World Health Organization regions, and China is considered to have momentum towards measles elimination. Therefore, this study aimed to assess the population immunity levels against measles and rubella in Zhejiang Province in China in order to provide valuable insights for informing future public health measures and contributing to the ongoing global campaign against these diseases. Materials and methods: A cross-sectional serological survey was conducted in 2022. A total of 2740 blood samples were collected from healthy individuals spanning the age range of 0–59 years, representing diverse demographic strata across 11 prefectures in Zhejiang Province in China. The sera were tested for measles and rubella IgG antibodies to determine positivity rates and geometric mean concentrations (GMCs). Results: The overall positivity rate for the measles IgG antibody was 85.3%, with a GMC of 588.30 mIU/mL. The positivity rate for the rubella IgG antibody was 70.9%, and the GMC was 35.30 IU/mL. Measles IgG antibody positivity rates across the 0–11 months, 12–23 months, 24–35 months, 3–5 years, 6–9 years, 10–14 years, 15–19 years, 20–29 years, and 30–59 years age groups were 63.1%, 92.5%, 97.0%, 94.0%, 85.8%, 77.3%, 86.9%, 84.9%, and 88.7%, respectively (trend χ² = 118.34, p < 0.001). Correspondingly, rubella antibody positivity rates for these same age brackets were 55.9%, 87.9%, 94.7%, 88.2%, 69.9%, 54.2%, 72.6%, 67.5%, and 74.3% (trend χ² = 199.18, p < 0.001). Both univariate and multivariate analyses consistently demonstrated that age, immunization history, and differing economic levels were significant factors contributing to variations in antibody levels. Conclusions: The seroprevalence of measles and rubella was lower than that required for herd immunity. Periodic vaccination campaigns should be launched to increase immunity.