Institute of Immunization and Prevention

Hangzhou, China

Institute of Immunization and Prevention

Hangzhou, China
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Hu Y.,Institute of Immunization and Prevention | Wang Y.,Institute of Immunization and Prevention | Chen Y.,Institute of Immunization and Prevention | Li Q.,Institute of Immunization and Prevention
Human Vaccines and Immunotherapeutics | Year: 2017

Objective: This study aimed to determine the degree and determinants of inequality in up-to-date fully immunization (UTDFI) coverage among children of Zhejiang province, east China. Method: We used data from the Zhejiang provincial vaccination coverage survey of 2014 and the health outcome was the UTDFI status among children aged 24–35 months. The household income per month was used as an index of socio-economic status for the inequality analysis. The concentration index (CI) was used to quantify the degree of inequality and the decomposition approach was applied to quantify the contributions from demographic factors to inequality in UTDFI coverage. Results: The UTDFI coverage was 80.63% and the CI for UTDFI coverage was 0.12028 (95% CI: 0.10852–0.13175), indicating that immunization practice significantly favored children with relatively higher socio-economic status. The results of decomposition analysis suggested that 68.2% of the socio-economic inequality in UTDFI coverage should be explained by the mother's education level. Furthermore, factors such as birth order, ethnic group, maternal employment status, residence, immigration status, GDP per-capital and percentage of public health spending of the total health spending also could explain the disparity in UTDFI coverage. Conclusion: There exists inequality in UTDFI coverage among the socio-economic disadvantage children. Health interventions of narrowing the socio-economic inequality in UTDFI coverage will benefit from being supplemented with strategies aimed at poverty and illiteracy reduction. © 2017 Taylor & Francis


Hu Y.,Institute of Immunization and Prevention | Chen Y.,Institute of Immunization and Prevention
International Journal of Environmental Research and Public Health | Year: 2017

Vaccination coverage in Zhejiang province, east China, is evaluated through repeated coverage surveys. The Zhejiang provincial immunization information system (ZJIIS) was established in 2004 with links to all immunization clinics. ZJIIS has become an alternative to quickly assess the vaccination coverage. To assess the current completeness and accuracy on the vaccination coverage derived from ZJIIS, we compared the estimates from ZJIIS with the estimates from the most recent provincial coverage survey in 2014, which combined interview data with verified data from ZJIIS. Of the enrolled 2772 children in the 2014 provincial survey, the proportions of children with vaccination cards and registered in ZJIIS were 94.0% and 87.4%, respectively. Coverage estimates from ZJIIS were systematically higher than the corresponding estimates obtained through the survey, with a mean difference of 4.5%. Of the vaccination doses registered in ZJIIS, 16.7% differed from the date recorded in the corresponding vaccination cards. Under-registration in ZJIIS significantly influenced the coverage estimates derived from ZJIIS. Therefore, periodic coverage surveys currently provide more complete and reliable results than the estimates based on ZJIIS alone. However, further improvement of completeness and accuracy of ZJIIS will likely allow more reliable and timely estimates in future. © 2017 by the authors.


Hu Y.,Institute of Immunization and Prevention | Hu Y.,Zhejiang University
International Journal of Environmental Research and Public Health | Year: 2015

Background: caregivers’ knowledge on vaccination is an important impact factor for their children’s vaccination status. The aims of this study were to evaluate the caregivers’ knowledge of vaccination, and to assess effectiveness of a health education seminar for improving caregivers’ knowledge on immunization. Methods: pre- and post-assessment design was adopted for a single group to evaluate the effectiveness of the health education seminar on vaccination. The seminar consisted of a lecture using simple understandable language. Improvements in total knowledge score before and after the seminar were assessed using a validated questionnaire that included ten questions. Description analysis and non-parametric tests were applied to evaluate and compare the vaccination knowledge level before and after the seminar. Results: 378 caregivers participated in this study. The majority were mothers. Of the ten questions, the correct response rates had significantly increased for nine questions after the education seminar. The mean total score of the assessment before the seminar was 5.2 ± 1.2 while that was 8.4 ± 0.9 for the assessment after the seminar, with a significant increase of 3.18 points. Conclusion: a short education seminar designed for caregivers had a remarkable effect on their vaccination knowledge. Health education on vaccination targeting migrant caregivers, caregivers with lower education level or household income, and employed caregivers are needed in future. © 2015 by the authors; licensee MDPI, Basel, Switzerland.


Sun M.,Institute of Immunization and Prevention | Ma R.,Institute of Immunization and Prevention | Zeng Y.,Institute of Immunization and Prevention | Luo F.,Institute of Immunization and Prevention | And 2 more authors.
Vaccine | Year: 2010

Objective: To properly evaluate the immunization status and determine risk factors of migrant children in 23 densely populated towns and townships in Beijing. Methods: A household cluster sampling survey was implemented and standard face-to-face interviews were conducted with 1820 migrant children aged 12-35 months. Demographic characteristics of the child and primary caregiver, the child's migrant characteristics, the primary caregiver's knowledge and attitude toward immunization, information about immunization services provided by the local clinic, and the child's immunization history were obtained. Weighted up-to-date (UTD) and age-appropriate immunization rates for the following four vaccines were assessed: three doses of diphtheria, tetanus and pertussis combined vaccine (DTP); three doses of oral poliomyelitis vaccine (OPV); three doses of hepatitis B vaccine (HepB); and one dose of Measles-containing vaccine (MCV). Weighted UTD and age-appropriate immunization rates for the overall series of these four vaccines (the 3:3:3:1 immunization series) were also estimated. Risk factors for not being UTD, being invalid and being delayed for the 3:3:3:1 immunization series were explored using both single-level and multi-level multinomial logistic regression models. Results: For each antigen, the weighted UTD immunization rate was above 83%, but the age-appropriate immunization coverages for HepB, OPV, DPT, and MCV were only 45.6%, 49.6%, 50.8% and 54.7%, respectively. The 1st dose was most likely to be invalid or delayed within HepB, OPV and DPT series. For the 3:3:3:1 immunization series, the weighted UTD and age-appropriate immunization rates were 78.1% and 20.5%, respectively. Immunization status of migrant children tended to be homogenous within a village and therefore, multi-level model was more appropriate for assessing risk factors. Besides demographic characteristics, several other factors were significantly associated with age-appropriate immunization coverage. These factors included: the child's migrant characteristics; the primary caregiver's awareness of the importance of vaccination, and outreach services provided by immunization clinics including notification services and supplementary immunization activities (SIAs). The frequency and duration of clinical immunization sessions significantly influenced the UTD immunization rate but not the age-appropriate immunization rate. The degree of the primary caregiver's satisfaction with clinic services and convenience to vaccination clinic had no impact on the child's immunization status. Conclusion: Alarmingly low age-appropriate immunization coverage of migrant children in densely populated areas demanded immediate intervention. Community context was an important factor to a migrant child's vaccination status and should be considered when taking measures. Strategies to strengthen outreach immunization service need to be developed to effectively improve the age-appropriate immunization coverage of migrant children. © 2009 Elsevier Ltd. All rights reserved.


Hu Y.,Institute of Immunization and Prevention | Li Q.,Institute of Immunization and Prevention | Luo S.,Institute of Immunization and Prevention | Lou L.,Institute of Immunization and Prevention | And 2 more authors.
PLoS ONE | Year: 2013

Background:The reported coverage rates of first and second doses of measles containing vaccine (MCV) are almost 95% in China, while measles cases are constantly being reported. This study evaluated the vaccine coverage, timeliness, and barriers to immunization of MCV1 and MCV2 in children aged from 8-48 months.Methods:We assessed 718 children aged 8-48 months, of which 499 children aged 18-48 months in September 2011. Face to face interviews were administered with children's mothers to estimate MCV1 and MCV2 coverage rate, its timeliness and barriers to vaccine uptake.Results:The coverage rates were 76.9% for MCV1 and 44.7% for MCV2 in average. Only 47.5% of surveyed children received the MCV1 timely, which postpone vaccination by up to one month beyond the stipulated age of 8 months. Even if coverage thus improves with time, postponed vaccination adds to the pool of unprotected children in the population. Being unaware of the necessity for vaccination and its schedule, misunderstanding of side-effect of vaccine, and child being sick during the recommended vaccination period were significant preventive factors for both MCV1 and MCV2 vaccination. Having multiple children, mother's education level, household income and children with working mothers were significantly associated with delayed or missing MCV1 immunization.Conclusions:To avoid future outbreaks, it is crucial to attain high coverage levels by timely vaccination, thus, accurate information should be delivered and a systematic approach should be targeted to high-risk groups. © 2013 Hu et al.


Hu Y.,Institute of Immunization and Prevention | Shen L.,Institute of Immunization and Prevention | Guo J.,Institute of Immunization and Prevention | Xie S.,Institute of Immunization and Prevention
International Journal of Environmental Research and Public Health | Year: 2014

Background: Vaccine-preventable diseases cause more than one million deaths among children under 5 years of age every year. Public Health Workers (PHWs) are needed to provide immunization services, but the role of human resources for public health as a determinant of vaccination coverage at the population level has not been assessed in China. The objective of this study was to test whether PHW density was positively associated with childhood vaccination coverage in Zhejiang Province, East China. Methods: The vaccination coverage rates of Measles Containing Vaccine (MCV), Diphtheria, Tetanus and Pertussis combined vaccine (DTP), and Poliomyelitis Vaccine (PV) were chosen as the dependent variables. Vaccination coverage data of children aged 13-24 months for each county in Zhejiang Province were taken from the Zhejiang Immunization Information System (ZJIIS). Aggregate PHW density was an independent variable in one set of regressions, and Vaccine Personnel (VP) and other PHW densities were used separately in another set. Data on densities of PHW and VP were taken from a national investigation on EPI launched by Ministry of Health of China in 2013. We controlled other determinants that may influence the vaccination coverage like Gross Domestic Product (GDP) per person, proportion of migrant children aged <7 years, and land area. These data were taken from Zhejiang Provincial Bureau of Statistics and ZJIIS. Results: PHW density was significantly influence the coverage rates of MCV [Adjusted Odds Ratio(AOR) = 4.29], DTP3(AOR = 2.16), and PV3 (AOR = 3.30). However, when the effects of VPs and other PHWs were assessed separately, we found that VP density was significantly associated with coverage of all three vaccinations (MCV AOR = 7.05; DTP3 AOR = 1.82; PV3 AOR = 4.83), while other PHW density was not. Proportion of migrant children < 7 years and Land area were found as negative and significant determinants for vaccination coverage, while GDP per person had no effect on vaccination coverage. Conclusions: A higher density of PHWs (VP) would improve the availability of immunization services over time and space, which may increase the possibility of achieving a higher childhood vaccination coverage rate. It was indicated that the level of GDP per person had no association with the improved vaccination coverage after controlling for other potential factors. Our findings implicated that PHW density was a major constraint on immunization coverage in Zhejiang Province. © 2014 by the authors; licensee MDPI, Basel, Switzerland.


Hu Y.,Institute of Immunization and Prevention | Chen E.,Institute of Immunization and Prevention | Li Q.,Institute of Immunization and Prevention | Chen Y.,Institute of Immunization and Prevention | Qi X.,Institute of Immunization and Prevention
Asia-Pacific Journal of Public Health | Year: 2015

The study aimed to assess the determinants of immunization coverage in children born in 2008-2009, living in Zhejiang Province. The World Health Organization's cluster sampling technique was applied. Immunization coverage of 5 vaccines was assessed: BCG vaccine, diphtheria and tetanus toxoids and pertussis vaccine, poliomyelitis vaccine, hepatitis B vaccine, and measles-containing vaccine. Determinants for age-appropriate immunization coverage rates were explored using logistic regression models. Immunization coverage of 5 vaccines were all greater than 90%, but the age-appropriate immunization coverage rates for 3 months and for first dose of measles-containing vaccine was 41.3% and 64.5%, respectively. Siblings in household, mother's education level, household registration, socioeconomic level of resident areas, satisfaction with clinical immunization service, and convenient access to local immunization clinic were associated with age-appropriate coverage rates. Age-appropriate immunization coverage rates should be given more attention and should be considered as a benchmark to strive for in the future intervention. © 2011 APJPH.


Hu Y.,Institute of Immunization and Prevention | Chen Y.,Institute of Immunization and Prevention | Guo J.,Institute of Immunization and Prevention | Tang X.,Institute of Immunization and Prevention | Shen L.,Institute of Immunization and Prevention
Human Vaccines and Immunotherapeutics | Year: 2014

Background: We studied completeness and timeliness of vaccination and determinants for low and delayed uptake in children born between 2008 and 2009 in Zhejiang province in eastern China. Methods: We used data from a cross-sectional cluster survey conducted in 2011, which included 1146 children born from 1 Jan 2008 to 31 Dec 2009. Various vaccination history, social-demographic factors, attitude and satisfaction toward immunization from caregivers were collected by a standard questionnaire. We restricted to the third dose of HepB, PV, and DPT (HepB3, PV3, and DPT 3) as outcome variables for completeness of vaccination and restricted to the first dose of HepB, PV, DPT, and MCV(HepB1, PV 1, DPT1, and MCV1) as outcome variables for timeliness of vaccination. The χ2 test and logistic regression analysis were applied to identify the determinants of completeness and timeliness of vaccination. Survival analysis by the Kaplan-Meier method was performed to present the timeliness vaccination. Results: Coverage for HepB1, HepB3, PV1, PV3, DPT1, DPT3, and MCV1 was 93.22%, 90.15%, 96.42%, 91.63%, 95.80%, 90.16%, and 92.70%, respectively. Timely vaccination occurred in 501/1146(43.72%) children for HepB1, 520/1146(45.38%) for PV1, 511/1146(44.59%) for DPT1, and 679/1146(59.25%) for MCV1. Completeness of specific vaccines was associated with mother' age, immigration status, birth place of child, maternal education level, maternal occupation status, socioeconomic development level of surveyed areas, satisfaction toward immunization service and distance of the house to immunization clinic. Timeliness of vaccination for specific vaccines was associated with mother' age, maternal education level, immigration status, siblings, birth place, and distance of the house to immunization clinic. Conclusion: Despite reasonably high vaccination coverage, we observed substantial vaccination delays. We found specific factors associated with low and/or delayed vaccine uptake. These findings can help to improve strategies such as Reaching Every District (RED), out-reach vaccination services and health education to reach children who remain inadequately protected. © 2014 Landes Bioscience.


Hu Y.,Institute of Immunization and Prevention | Li Q.,Institute of Immunization and Prevention | Chen E.,Institute of Immunization and Prevention | Chen Y.,Institute of Immunization and Prevention | Qi X.,Institute of Immunization and Prevention
International Journal of Environmental Research and Public Health | Year: 2013

Objective: To determine the coverage of childhood immunization appropriate for age among socio-economically disadvantaged recent migrants living in East China and to identify the determinants of full immunization uptake among these migrant children. Methods: This is a cross-sectional survey of 1,426 migrant mothers with a child aged ≤24 months, who were interviewed with a pretested questionnaire. Various vaccines, migration history and some other social-demographic and income details were collected. Single-level logistic regression analyses were applied to identify the determinants of full immunization status. Results: Immunization coverage rates are lower among migrants and even lower among recent migrants. The likelihood of a child receiving full immunization rise with parents' educational level and the frequency of mother's utilization of health care. Higher household income also significantly increase the likelihood of full immunization, as dose post-natal visits by a health worker. Conclusions: Recent migrant status favours low immunization uptake, particularly in the vulnerability context of alienation and livelihood insecurity. Services must be delivered with a focus on recent migrants. Investments are needed in education, socio-economic development and secure livelihoods to improve and sustain equitable health care services. © 2013 by the authors; licensee MDPI, Basel, Switzerland.


PubMed | Institute of Immunization and Prevention
Type: Journal Article | Journal: International journal of environmental research and public health | Year: 2016

In 2014 a 2-doses varicella vaccine (VarV) schedule was recommended by the Zhejiang Provincial Center for Disease Control and Prevention. We aimed to assess the coverage of the 1st dose of VarV (VarV) and the 2nd dose of VarV (VarV) among children aged 2-6 years through the Zhejiang Provincial Immunization Information System (ZJIIS) and to explore the determinants associated with the VarV coverage.Children aged 2-6 years (born from 1 January 2009 to 31 December 2013) registered in ZJIIS were enrolled. Anonymized individual records of target children were extracted from the ZJIIS database on 1 January 2016, including their VarV and (measles-containing vaccine) MCV vaccination information. The VarV and VarV coverage rates were evaluated for each birth cohorts. The coverage of VarV also was estimated among strata defined by cities, gender and immigration status. We also evaluated the difference in coverage between VarV and MCV.A total of 3,028,222 children aged 2-6 years were enrolled. The coverage of VarV ranged from 84.8% to 87.9% in the 2009-2013 birth cohorts, while the coverage of VarV increased from 31.8% for the 2009 birth cohort to 48.7% for the 2011 birth cohort. Higher coverage rates for both VarV and VarV were observed among resident children in relevant birth cohorts. The coverage rates of VarV and VarV were lower than those for the 1st and 2nd dose of MCV, which were above 95%. The proportion of children who were vaccinated with VarV at the recommended age increased from 34.6% for the 2009 birth cohort to 75.2% for the 2013 birth cohort, while the proportion of children who were vaccinated with VarV at the recommended age increased from 19.7% for the 2009 birth cohort to 48.7% for the 2011 birth cohort.Our study showed a rapid increasing VarV coverage of children, indicating a growing acceptance of the 2-doses VarV schedule among childrens caregivers and physicians after the new recommendation released. We highlighted the necessity for a 2-doses VarV vaccination school-entry requirement to achieve the high coverage of >90% and to eliminate disparities in coverage among sub-populations. We also recommended continuous monitoring of the VarV coverage via ZJIIS over time.

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