Background: Routine immunisation (RI) contributes immensely to reduction in mortality from vaccine preventable diseases (VPD) among children. The Nigerian Demographic and Health Survey, 2008 revealed that only 58 % of children in Osun State had received all recommended vaccines, which is far below World Health Organization (WHO) target of 80 %. We therefore, assessed RI uptake and its determinants among children in Atakumosa-west district of Osun State. Methods: Atakumosa-west district has an estimated population of 90,525 inhabitants. We enrolled 750 mothers of children aged 12-23 months in this cross-sectional study. Semi-structured questionnaires were used to obtain data on socio-demographic characteristics, knowledge of mothers on RI, history of RI in children and factors associated with full RI uptake. A fully-immunised child was defined as a child who had received one dose of Bacillus-Calmette-Guerin, three doses of Oral-Polio-Vaccine, three doses of Diptheria-Pertusis-Tetanus vaccine and one dose of measles vaccine by 12 months of age. We tested for the association between immunisation uptake and its likely determinants using multivariable logistic regression at 0.05 level of significance and 95 % confidence Interval (CI). Results: Mean ± (SD) age of the mothers and children were 27.9 ± 6.1 years and 17.2 ± 4.0 months, respectively. About 94 % (703/750) of mothers had received antenatal care (ANC) and 63.3 % (475) of the children possessed vaccination cards. Seventy-six percent (571/750) had good knowledge of RI and VPD. About 58 % (275/475) of children who possessed vaccination card were fully-immunised. Mothers antenatal care attendance (aOR = 3.3, 95 % CI = 1.1-8.3), maternal tetanus toxoid immunisation (aOR = 3.2, 95 % CI = 1.1-10.0) access to immunisation information (aOR = 1.8, 95 % CI = 1.1-2.5) and mothers having good knowledge of immunisation (aOR = 2.4, 95 % CI = 1.6-3.8) were significant determinants of full immunisation. Conclusions: Routine immunisation uptake was still below WHO target in the study area. Encouraging mothers to attend antenatal care and educational interventions targeted at rural mothers are recommended to improve vaccination status of children in the rural communities.
We conducted this study in Atakumosa-west district which is a predominantly rural district in Osun State, south-western Nigeria. It had an estimated population of 90,525 inhabitants based on the 2007 population census [11]. Atakumosa-west district is made up of eleven wards with about 170 widely distributed settlements. The Yorubas are the main ethnic tribe residing in the area most of whom are farmers. There are 27 primary health centers and two comprehensive health centers all of which provide routine immunisation. We conducted a community-based cross-sectional study between September and October 2013. Mothers of children 12–23 months old who were resident in the district at the time of the survey were interviewed. At the time of the study, children 12–23 months of age were considered eligible for sampling. We used the method in the WHO immunization coverage cluster survey reference manual to determine the sample size based on a full immunisation coverage of 57.8 % [9], significance level of 5 % corresponding to a standard normal deviate (z) of 1.96, precision of 5 % and design effect (DEFF) of 2 and obtained a minimum sample size of 750 children [12]. We used a two-stage cluster sampling technique to sample eligible children. At stage one (selection of clusters), we selected 30 clusters from the available 170 clusters based on probability- proportional- to- size of the population. In stage two (selection of households), we selected 25 households from each of the 30 clusters selected at stage one. The first household in each cluster was selected randomly and subsequent households were selected contiguously in the right direction until the required number of households for that cluster was achieved. From each selected household, one eligible child was selected. If a selected household had more than one eligible child, only one was randomly selected. If a selected household had no eligible child, the next contiguous household was visited and one eligible child selected. We sampled an equal number of children from each of the 30 clusters [12]. Thus, 25 children were sampled per cluster, giving a total sample size of 750 children. Data for the study were collected by 15 trained community health extension workers using standardised structured and pretested interviewer-administered questionnaires. The questionnaires were administered in ‘Yoruba’; the predominant spoken language and back translated to English to avoid any ambiguity. Data collected include socio-demographic characteristics of mothers and children, knowledge of mothers regarding routine immunisation, vaccination status of children and reasons for incomplete or non-vaccination. If a card was available, the interviewer recorded the vaccination information and dates of each vaccination received by the child. If a child had never received a vaccination card, or the mother was unable to show the card to the interviewer, the vaccination information for the child was based on the mother’s report. To assess the knowledge of mothers, responses were scored using six questions on various aspects of routine immunisation. The questions assessed respondent’s ability to state: the correct purpose of immunisation, correct age a child should receive second dose of RI vaccinations, last dose of RI vaccines, total number of visits a child should make to the health facility to receive all recommended doses, at least three symptoms of vaccine preventable diseases and at least three vaccine preventable diseases. Each correct response was scored one point while each wrong response was scored zero. Mothers who scored three points and below were graded as having poor knowledge while those who scored four points and above were graded as having good knowledge. This scoring system is similar to that used in determining vaccination coverage in Nigeria [9]. Based on the type and doses of RI antigens received, we categorized the children as fully immunised, partially immunised, or un-immunised. We defined a “fully immunised child” as a child who had received one dose of BCG, three doses of OPV (excluding OPV given at birth), three doses of DPT vaccine and one dose of measles vaccine by 12 months of age; “partially immunised child” a child who missed at least any one of the above doses; “un-immunised child” a child who had not received any vaccine by 12 months of age [13]. Data were entered, cleaned and edited for inconsistencies before analyzing with Epi info version 7. Descriptive analysis was done and the results were summarized as frequencies and proportions for categorical variables and means and standard deviations (SD) for continuous variables. During bivariate analysis, associations between categorical variables were assessed using the Chi square test at 95 % Confidence Interval (CI). A multivariable logistic regression model with full immunisation status as dependent variable was built to rule out possible confounders. All analyses were done at 95 % CI and 0.05 level of significance.