Factors affecting childhood immunization in Lao People's Democratic Republic: a cross-sectional study from nationwide, population-based, multistage cluster sampling.

Vaccines are one of the most important achievements in public health, and a major contributor to this success is the Expanded Programme on Immunization (EPI). The effective vaccination series of the EPI should be used by its target population. Various factors influence the utilization of the EPI vaccination series. In Lao People's Democratic Republic (Lao PDR), immunization coverage was lower than the regional average. This study evaluates risk factors affecting immunization underutilization among children five to nine years of age. It is a cross-sectional study from nationwide, population-based, multistage cluster sampling. The children who have received 'standard six' antigens and those who have been partially immunized are compared. In a bivariate analysis, household occupation, maternal age, means of transportation, time to the nearest health facilities, the child's birthplace, birth attended by medical staff, and notification of vaccination date by medical staff, village authority, or megaphone were associated with vaccination status. The final multivariate logistic regression model revealed that maternal age and notification of vaccination date by the village authority increased the odds of full vaccination, while notification of vaccination date by megaphone had decreased those odds. Further detailed qualitative research may be needed to discover how maternal sociodemographic factors influence the utilization of these services. Future research needs to target younger children and must include health care provider factors related to vaccination services.