Factors associated with non-uptake of measles-rubella vaccine second dose among children under five years in Mtwara district council, Tanzania, 2017

Introduction in 2014, Tanzania introduced the combined measles-rubella vaccine in the routine immunization schedule. Two doses of measles-rubella vaccine (MR1 and MR2) are recommended at 9 and 18 months, respectively. In 2015, MR2 coverage among eligible 18-month-old children in Tanzania was only 57%, lower than the WHO-recommended coverage (95%). During the same period Mtwara District Council (MDC) reported a coverage of 52% which is lower than the nation average. We determined factors associated with non-uptake of MR2 among children in MDC Tanzania. Methods we conducted a community-based cross-sectional survey using cluster sampling during January - April 2017 in MDC. Caretakers of children born during January 2014 - January 2015 and residing in MDC for the past three years were recruited. We interviewed participants and reviewed vaccination cards. Logistic regression modeling was employed to identify independent factors associated with uptake of MR2. Results of 1,000 children assessed, 558 (55.8%) were unvaccinated with MR2. Factors independently associated with non-uptake of MR2 included the caretaker being unaware of the ages for MR1 and MR2 administration [aOR=3.50; 95%CI 1.98-6.21; p<0.001], having MR2 vaccination services offered at the local vaccination station fewer than three days per week [aOR=1.50; 95%CI 1.42-5.59; p<0.001], not having the vaccine available during vaccination days [aOR=3.38; 95%CI 1.08-10.61; p<0.01], unwillingness of health workers to open multi-dose vaccine vials for a single child [aOR=3.80; 95% CI 2.12-6.79; p<0.001], and long waiting times for vaccination services [aOR=1.80; 95% CI 1.08-3.00; p<0.01]. Conclusion more than half the children under five years in MDC were not vaccinated with MR2. Lack of caretaker knowledge about appropriate vaccination age, unavailability of vaccine, having insufficient numbers of children waiting to warrant multidose vial use, and long clinic waiting times were associated with MR2 non-uptake. The community should receive education about MR vaccine; we recommend thorough screening of children?s vaccination status at each clinic visit and provision of vaccine whenever possible. Vaccine distribution should be improved in MDC.


Study area
Mtwara District Council is one of seven councils in Mtwara region in Elderly, and Children. The report described several regions that did not reach the ≥95% coverage MR2 targets, including Dar-es-Salaam, Lindi, Mtwara, Njombe, Coastal, Tanga, Morogoro, and Mwanza regions. Mtwara region was randomly selected from this list, after which Mtwara District Council was randomly selected from the seven regional councils as the study area. This area is inhabited by peasants and petty business [2] and had 28 health facilities providing vaccination services.

Study design
A cross-sectional community-based study was conducted in which 1,000 mothers of children born during January 2014 to January 2015 were interviewed and vaccination cards for children were reviewed.
This study was undertaken during January -April 2017. Participants had to be residents of the study area for at least the past three years and have at least one child born during the period of interest. We employed multistage cluster sampling to select 10 of the 21 area wards and five villages from each ward. Sample size per village was calculated proportionate to population size of the selected 50 villages.
Bottle spinning was employed to select the starting household from which a mother/guardian was selected for interview. If the household did not have a mother of a child born during January 2014 to January 2015, the nearest neighbor household was used to replace that participant. Data were collected from guardians/mothers using a pretested semi-structured questionnaire administered at home. If the household had more than one eligible child, the parent/guardian responded for an older child. Information collected included sociodemographic characteristics, awareness of the MR2 vaccine, vaccination status of the child, and characteristics about the vaccination health facility used by the family. Child vaccination cards were examined to assess the vaccination status of the children.

Data management and analysis
Data were entered into EpiInfo version 3.5.1. Categorical variables were summarised in proportions. Differences between proportions were examined using chi-square test. For continuous variables, medians and interquartile ranges (IQR) were calculated. Bivariate and multivariate analyses were conducted to identify independent factors associated with non-uptake of MR2. Odds Ratios (OR) and adjusted Odds Ratios (aOR) and 95% Confidence Intervals (CI) were calculated. All analyses were two-tailed and the significance level was set at 5%.

Socio-demographic characteristics of mothers and children recruited in the study
A total of 1,000 mothers of children aged <5 years were interviewed. were married and the principal occupational activity was "informal employment" (91.0%) ( Table 1). Proportion of measles-rubella second dose (MR2) non-uptake by card verification. Of 1,000 children with vaccination cards reviewed, 558 (55.8%) did not receive MR2.
Ndumbwe and Mpapura wards, neighboring wards which share the same health facility as well as the same vaccination post, had the highest proportions of unvaccinated children (81.0% and 72.2%, respectively) ( Table 2).

Factors associated with non-uptake of MR2 Vaccine
Mothers who had completed primary education or no formal education were more likely than mothers with secondary or higher

Discussion
We investigated factors associated with non-uptake of the second dose of measles-rubella vaccine in Mtwara district council of Tanzania, a district experiencing very poor coverage. We found that more than half of eligible children in the area were unvaccinated, falling short of the 95% coverage target for elimination of measles worldwide [3]. In this study, we found that unavailability of MR vaccine during scheduled vaccination days was significantly associated with nonuptake of MR2 among children in the community. This finding is consistent with previous studies [7][8][9][10]. This may be most easily  Tables   Table 1: socio-demographic of mothers and their children recruited in the study, Mtwara district council, Tanzania, 2017 Table 2: proportion of measles-rubella second dose (MR2) nonuptake by card verification Table 3: independent factors associated with non-uptake of MR2 among under fives children in Mtwara district council  1 OR = Odds ratio, aOR = Adjusted odds ratio, % = percentage, 1 = reference variable C. I. = Coefficient interval. * = p< 0.01, ** = p< 0.001, *** = p < 0.05 and-* = p ≥ 0.05.