SOCIOECONOMIC FACTORS AFFECTING VACCINATION COVERAGE AND TIMELINESS AMONG CHILDREN LIVING ALONG THE THAI-MYANMAR BORDER
Keywords:vaccination coverage, vaccination timeliness, Thailand-Myanmar border, migrant, expanded program on immunization, immunization
Vaccination coverage in children may be inadequate among those living in areas with poor access to health care facilities potentially causing disease outbreaks. We assessed vaccination coverage and timeliness among children living in Thailand along the Thai-Myanmar border and assessed the factors associated with these findings in order to inform efforts to improve vaccination rates. We conducted a cross-sectional study at 11 child development centers run by the Mae Song Sub-district administrative office, Tha Song Yang District, Tak Province, Thailand from January to May 2018. The vaccination records for the first year of life used to obtain data for this study were from child health booklets, other documents and records from the extended program of immunization (EPI) register database for the Mae Song Health Promotion Hospital, a primary health facility in the study area. Anthropometry of the study subjects was measured by the study team. Caregivers of the study subjects were asked to complete a questionnaire asking about socio-demographic factors, household income, subject birth place, vaccination history and birth order. A total of 304 subjects were included in the study; 50.2% male. The mean (±standard deviation; range) age of study subjects was 4.5 (±1.1, 2-6 years). Majority (95.3%) of subjects had received the Bacillus Calmette-Guérin (BCG) vaccine, 87.1% had received the third dose of the diphtheria, tetanus, pertussis (DTP) vaccine; 87.1% had received the third dose of the hepatitis B (HepB) vaccine, 87.1% had received the third dose of the oral poliovirus (OPV) vaccine and 93.6% had received the first dose of the measles, mumps, Rubella (MMR) vaccine. Sixty-two-point-seven (62.7) percent of subjects had received all the above vaccine doses by age 12 months. The median delays in receiving vaccination doses were: 7.7 weeks for the birth dose of the HepB vaccine, 14.8 weeks for the third dose of the DTP vaccine, 14.8 weeks for the third dose of the HepB vaccine, 14.8 weeks for the third dose of the OPV vaccine and 22.6 weeks for the first dose of the MMR vaccine. Fifteen-point-one (15.1) percent of study subjects received timely vaccinations. The factors significantly associated with vaccination coverage and timeliness were: the caregiver being literate in the Thai language (adjusted odds ratio (aOR): 2.1, 95% confidence interval (CI): 1.1-3.9, p = 0.018), the study subject being aged 2-4 years (aOR: 2.3, 95% CI: 1.1-4.5, p = 0.024) the study subject being the first or second born child (aOR: 1.9, 95% CI: 1.1-3.2, p = 0.028) and vaccinations being given at the Health Promotion Hospital (aOR: 2.1, 95% CI: 1.3-3.6, p = 0.005). In summary, among study subjects the vaccination coverage was inadequate (<90%) for the BCG, HepB, OPV and DTP vaccines but adequate for the MMR vaccine during the first year but the great majority of vaccines were not given in a timely manner and the factors associated with this were the caregiver being literate, a young study subject, the birth order of the study subject and where the vaccines are given. We conclude, timely reminders need to be given to caregivers, especially to those who are illiterate in the Thai language, those who have at least 3 children, those with older children and those who do not live near a hospital, in order to improve first year vaccination rates in the study population. Further studies are needed to determine if these efforts can improve these vaccination rates.