PUB - Publikationen an der Universität Bielefeld

- Background Vaccination is one of the most successful and effective tools for preventing infectious diseases. However, despite the well-established benefits of vaccinations many children in different regions of the world remain unvaccinated. - Objectives The aim of this dissertation was to describe a vaccination process in a transitional country, using the example of Kyrgyzstan. Among the specific aims of this dissertation was an analysis of factors associated with children's vaccination status. The study also aimed to assess parental attitudes towards childhood vaccinations and to analyze factors associated with them. An important aim of this study was an assessment of up-to-date and age-appropriate vaccination. Based on the results of the dissertation recommendations should be given to vaccination policy makers. - Methods Three sources of data were used in this work to answer different aims of the study. For the assessment of up-to-date vaccination, all three data sets were used, namely, the Demographic and Health Survey (DHS) (1997), the Multiple Indicator Cluster Survey (MICS) (2005) and data from an own cross-sectional study, conducted in the capital of Kyrgyzstan, Bishkek, in September 2006. - Results Up-to-date vaccination coverage The up-to-date vaccination coverage based on all three data sources was at relatively high levels but lower than reported by the local Ministry of Health. According to the DHS data, up-to-date vaccination coverage among children of 12 to 35 months of age ranged between 90 percent (measles vaccine) and 99 percent (first dose of polio vaccine). According to the MICS data, up-to-date coverage among children of 12 to 59 months of age was highest for vaccine against tuberculosis (99 percent) and lowest for vaccine against measles (95 percent). At least one dose of DTP- and polio vaccines received 99 percent and 97 percent of children, respectively. However, a lower proportion of children was completely immunized with all three doses (52 percent with DTP-vaccine and 60 percent with polio vaccine). About 24 percent and 15 percent of children received only one dose of DTP- and polio vaccines. According to the study conducted in the capital Bishkek, 96 percent of first-year pupils (6-7 years of age) were vaccinated against tuberculosis and 89 percent against measles. At least one dose of hepatitis B, DTP- and polio vaccines was administered to 81 percent, 94 percent and 96 percent of children, respectively. However, only 83 percent of those children were vaccinated completely with all three doses of DTP- and polio vaccines and 77 percent with all three doses of hepatitis B vaccine. Age-appropriate vaccination The age-appropriate vaccination was much lower compared to up-to-date vaccination. A substantial proportion of children was vaccinated with a considerable delay. About 85 percent (95 percent CI: 82.6-87.8) of children were vaccinated with a first dose of DTP-vaccine without any delay, 74 percent (70.1-79.2) with a second dose and 62.9 percent (59.3-66.6) with a third dose. Although polio vaccine should be administered at the same schedule as DTP-vaccine, there were some differences in age-appropriate vaccination. About 85 percent of children were vaccinated with a first dose of polio vaccine, but only about 65 percent and 59 percent with second and third doses, respectively. Only 75 percent of children received vaccine against measles without any delay. Parental attitudes towards vaccination The perceived importance of childhood vaccinations among parents was at very high level; about 96 percent of parents believed that vaccinations were important (about 40 percent very important). The overwhelming majority of parents had positive attitudes towards vaccination. However, a small proportion of parents expressed some concerns regarding vaccine safety. Moreover, about 15 percent of parents were opposed to mandatory vaccinations and about 5 percent had strong anti-mandatory attitudes. Lower education of both parents was associated with higher vaccine safety concerns and higher anti-mandatory attitudes. Parents whose children had allergies, were also more likely to have higher vaccine safety concerns and higher anti-mandatory attitudes. Internal migration was also associated with anti-mandatory attitudes; parents, who migrated to the capital from other urban regions, were more likely to have anti-mandatory attitudes. About 11 percent of parents would refuse childhood vaccinations if they had another child in the future. Factors associated with incomplete or missing vaccination Multilevel logistic regression analyses of the MICS data showed that the only variable significantly associated with the incomplete vaccination status of children was the wealth index. The risk of not being completely vaccinated with DTP and polio vaccine was higher among children from poorer families compared to those from richest families. Results of the study conducted in the capital Bishkek showed that children who were not born in the capital, with parents with no sources of vaccinations and with a poor access to health care were more likely not to be vaccinated with the measles vaccine. The same pattern of association was observed for vaccine against hepatitis B. Furthermore, children whose parents had concerns about vaccine safety were also more likely not to be vaccinated against hepatitis B. - Conclusions Up-to-date vaccination coverage was at high levels according to all data sources and was higher compared to other developing and even developed countries. Considerable proportion of children was vaccinated with delay. Factors associated with no vaccination were a mixture of patterns observed both in developing and developed countries. Some parents had concerns about vaccine safety and a small proportion of parents had anti-mandatory attitudes. Policy makers should take these findings into consideration in order to adequately plan vaccination programmes.