Elsevier

Vaccine

Volume 25, Issue 4, 8 January 2007, Pages 664-671
Vaccine

Immunization coverage and its determinants in children aged 12–23 months in Gansu, China

https://doi.org/10.1016/j.vaccine.2006.08.027Get rights and content

Abstract

The study aimed to assess the determinants of immunization coverage in 12–23-month-old children born in 1997 and living in Gansu Province in West China. The World Health Organization's cluster sampling technique was used. Information was gathered by face-to-face interviews with caregivers and from immunization records. Bacille Calmette Guerin (BCG), Polio and Diphtheria, Tetanus, Pertussis (DTP) coverage at 3 months was 51.2%. At 8 and 12 months, including the Measles Vaccine, coverage was 71.3 and 86.0%, respectively. The variables associated with delay at 12 months were: low socio-economic level, low number of sources of information on vaccination and delayed immunization at 3 months. Improved immunization coverage could be achieved by improving access and delivery to poor and remote areas and by awarding incentives to providers at primary care level.

Introduction

Vaccination has been regarded as one of the 10 most important achievements of public health in the 20th century [1]. It is also considered the most cost-effective preventive health service for children [2], [3], [4]. Immunization coverage rates are accepted as an indicator of the performance and adequacy of primary pediatric health care services [5] and are also a useful tool in program management and decision making [6]. Vaccination coverage is primarily hampered by difficulty in accessing medical care, and by costs, complex transport and storage requirements, and by users characteristics, such as education and low parental knowledge, late birth order, family size and poverty [7], [8], [9], [10], [11]. In China, in addition to these factors, the migration of children from one region to another (they are part of the “floating population”) [12] has also been found to be associated with low vaccination coverage in particular for Hepatitis B Vaccine (HBV) [13].

There are also concerns as to the effect that the economic transition in China is having upon the health status of the population and their health care, with increasing inequalities and rural-urban divide [14], [15].

The goal for immunization coverage in China for the year 1995 was set at 85% for the 1:3:3:1 vaccine series (one dose of Bacille Calmette Guerin; BCG, three doses of Diphtheria, Tetanus, Pertussis; DTP, three doses of Oral Polio Vaccine; OPV and one dose of Measles Vaccine; MV). This rate has been achieved every year since 1995, although there are discrepancies between the coverage rate (at 12 months) for the three DTP doses as reported by Ministry of Health (MoH) and the coverage rate estimated by the World Health Organization (WHO): 98 and 79%, respectively, in the year 2002 [16], [17]. Additionally, overall figures do not always reflect the situation in different areas within a country.

A review of surveillance data from the Gansu Provincial Center for Disease Control and Prevention by one of the authors (F-Q C) found that the incidence of Polio and Diphtheria in the province has been nil since 1993. During the period 2000–2005, the incidence of Hepatitis B was 190 per 100,000 and of Tuberculosis, 76 per 100,000. The incidence of Measles was 13.0 per 100,000 in 2005, but there have also been outbreaks over the years.

Since the 1970s, the Chinese MoH, in collaboration with the United Nations Children's Fund (UNICEF) and the WHO, has equipped different levels of immunization stations and maintained the cold chain vaccine delivery to them. Vaccines are available and free to all children, based on the Expanded Program of Immunizations (EPI) schedule (1:3:3:1 series). Other vaccines, such as HBV, were introduced into the routine immunization schedule in 1992 (at a cost of about US$ 3 for three doses) but provided free of charge since 2002 (but with a user fee of about US$ 1.1). Gansu Province follows the national immunization schedule, as indicated in Table 1. Vaccines are purchased by the Provincial Disease Control Department and delivered from the province to the prefecture, to the county, to the township and finally to the local immunization stations in the villages. Vaccine delivery to the immunization stations is generally made every other month. The majority of immunizations are administered around the time the vaccines arrive, with the supply being fully consumed at this time. As a consequence, and compounded by breakdowns in the cold chain, some areas suffer an inadequate supply of vaccines for relatively long periods of time.

Immunizations are administered by the primary health care services, which in rural areas usually means the village doctors, i.e., the ‘barefoot doctors’ (who get 3–6 months training after junior high school and 2–3 weeks of in-service training per year thereafter), or the health workers at the township hospital. The village doctor does not receive a government salary and is only allotted a small incentive payment from the village budget. The Chinese government decreased the immunization budget over the years, making out-of-pocket payments for this service necessary [15]. Village doctors could charge for immunizations (about 20 cents per dose, for the 1:3:3:1 series). Since 2005, a decision of the central government has made all immunization services free, with no extra fee for service. In addition, provincial health departments sell immunization insurance (a kind of agreement signed between the doctor and the parent, whereby the parent receives a refund in the event that the child contracts the particular disease, covered by the insurance, which the immunization should have prevented). The fee for services and the insurance, although affordable by most people, posed an additional burden to families, particularly poor ones.

In this study, we aim to assess the immunization coverage for the 1:3:3:1 series and for HBV, and the determinants of this coverage in Gansu Province in West China.

Section snippets

Study population

The study population was made up of caregivers of children, residents in Gansu Province. The children were aged 12–23 months at the time of interview (i.e., born between January 1, 1997 and December 31, 1997). Caregivers who were not local residents were included in the sample if they had been living in the province for at least 3 months following the child's birth. Children were excluded if they were born in other provinces and had been living in Gansu for less than 3 months. If there was more

Results

Most of the respondents were of Han origin (94%). Their socio-demographic characteristics are presented in Table 2. There was a higher proportion of boys than girls; 68% were first-borns; more than half were born at home and 77% lived in rural areas. Most of the mothers were peasants and 57% did not have formal schooling or had only finished primary school.

Discussion

The results with regard to the four-vaccine series showed that even though there was a relatively low coverage rate at 3 and 8 months, there was catch-up by 12 months. However, for HBV a very low proportion of the children were Appropriate for age or Up to date immunized. According to these findings, the MoH's goal of 85% coverage was attained, although it was lower than the 1999 coverage rate as reported by the MoH (98%) [19] and higher than that estimated by the WHO (89%) [20]. Overall

Acknowledgements

Our thanks go to our colleagues at province and prefecture level, and to the village doctors from 72 counties for their data collection. Also to Ms. Bella Adler of the Braun School of Public Health and Community Medicine, Hebrew University, Hadassah, for her statistical advice.

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