Factors associated with vaccination status in children under 5 years of age in two communities in South Africa

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Epidemiology in the field of Epidemiology & Biostatistics November 2016Background The vaccination coverage estimates reported for South Africa by WHO are below the 90% target indicating that many children in South Africa remain unvaccinated. Data on proportion of children with delayed vaccination and factors leading to missed and delayed vaccination are limited in this setting. The aim of this study was to describe the vaccination coverage and assess factors associated with missed and delayed vaccination in South Africa. Methods and material A secondary data analysis which used data from two Healthcare Utilisation Surveys was conducted in Soweto, Johannesburg in 2012 and in Edendale, Pietermaritzburg in 2013. The analysis was restricted to children aged less than 5 years who had immunisation cards/ vaccine histories. Vaccination coverage and proportion of children with delayed vaccination were calculated for each vaccine dose recommended during the first year of life as described in the South Africa Expanded Programme on Immunisation. Pearson’s Chi square test and Fisher’s exact test were used to compare vaccination coverage across sites. Factors association with delayed and missed third doses of the Diphtheria Tetanus Pertussis vaccine (DTP3) were assessed using univariate and multivariate logistic regression models. Results Vaccination coverage was high (above 90%) for most vaccines except for the third dose of the pneumococcal conjugated vaccine (PCV3) and the second dose of rotavirus vaccine, which had coverage of 80.3% and 85.4% respectively. In Edendale, the coverage for all vaccines appeared to be lower than in Soweto. Vaccination coverage in Soweto ranged from 83.4% to 99.4% and 66.9% to 95.9% in Edendale. In Soweto, DTP3 coverage decreased significantly from 2008 to 2012 (p<0.0001). The highest DTP3 coverage in Soweto was in children aged 48-59 months (98.4%, p<0.0001). In Edendale there was no significant trend observed in coverage by age group or year. A higher proportion of delayed DTP3 vaccination was observed among children aged 12-23 months in Soweto (36.7%, p=0.007) and among children aged 36-47 months in Edendale (42.3%, p<0.0001). Delays were more common in children born in 2010 (47.2%, p