Vaccination coverage and its associated factors among infants in Kamukunji Sub-County, Nairobi, Kenya

Abstract

Background: Childhood vaccination is an important cost-effective public health intervention. It prevents illnesses, disabilities, and deaths/from vaccine preventable diseases. The World Health Organization (WHO) recommends 90% vaccination coverage for herd immunity to develop. The global vaccination coverage has stalled at 86% between 2015 and 2016.The poor vaccination coverage led to close to 19.5 million infants across the world missed out on basic vaccines in 2016, majority of them in sub-Sahara Africa. In Africa, vaccination coverage was 80%, the lowest ever in the world. Kenya’s vaccination coverage of 69% in 2016 and 63% in 2017 were suboptimal to prevent vaccine preventable diseases. In Kamukunji sub-County, there were reported cases of polio and measles outbreaks in 2018. Objectives: To determine coverage of fully vaccinated, vaccination coverage of each antigen and describe socio-demographic and health facility factors associated with vaccination uptake among infants in Kamukunji sub-County, Nairobi County, Kenya Methods: A cross-sectional study was carried out targeting infants aged 3 to 11 months old. Multistage sampling that included simple random sampling and modified WHO 30x7 cluster method was used to enroll 510 infants. Interviewer-administered questionnaires and data abstraction tool were used to collect data from caretakers and abstract data from vaccinating facilities and patient cards. Descriptive analysis was done using measures of central tendency and dispersion for continuous data and frequency and proportions were used for discrete data. Chi square test was used to assess the association between vaccination status and independent variables. Factors with P value <0.2 were entered into unconditional logistic regression analysis and factors with P value <0.05 were considered significantly associated with vaccination coverage. Results: Five hundred and ten (510) infants, aged 3 to 11 months with a mean age of 9 months were interviewed, 174 (34.1%) infants were not fully vaccinated according to their ages. Infants aged 3 to 5 months had 25.9%, 6 to 8 months had 53.2% while 9 to 11 months had 78.4% full vaccination coverage. All antigens had vaccination coverage of 80% and above except second dose of Rota virus vaccine (Rota2) with 78.4%. Half of vaccinating facilities attained 80% targeted vaccination coverage. Factors associated with infants’ vaccination in Kamukunji included age [aORs 0.09 (P value 0.000) for 3 to 5 months old and 0.45 (P value 0.001) for 6 to 8 months old] and distant to vaccinating facilities [aORs 0.35 (P value 0.002) for 0.5 Km to 1 Km and 0.20 (P value 0.000) for >1 Km to 5 Km]. The main (97.1%) reason of non-vaccination was not being aware of subsequent doses. Conclusion: Full vaccination coverage according to age was suboptimal. Older infants were more likely to be fully vaccinated. Longer distance to facilities had negative effect on vaccination. Recommendation: The county government should increase the number of vaccinating facilities to reduce the distance. Health facilities to put in place measures to remind the caretakers of subsequent vaccination visits