Cost-effectiveness analysis of routine immunization and supplementary immunization activity for measles in a health district of Benin

Background: This study was carried out at district level to describe the cost structure and measure the effectiveness of delivering supplementary immunization activity (SIA) and routine immunization (RI) for measles in Benin, a country heavily affected by this disease. Methods: This cost-effectiveness study was cross sectional and considered 1-year time horizon. RI consists to vaccinate an annual cohort of children aged 0-1year old and SIA consists to provide a second dose of measles vaccine to children aged 0-5years old in order to reach both those who did not seroconvert and who were not vaccinated through RI. Ingredients approach to costing was used. Effectiveness indicators included measles vaccine doses used, vaccinated children, measles cases averted and disability adjusted life years averted. Data were collected from all the 18 health care centers of the health district of Natitingou for the year 2011. In the analysis, the coverage was 89% for RI and 104% for SIA. Results: SIA total cost was higher than RI total cost (15,796,560 FCFA versus 9,851,938 FCFA). Personnel and vaccines were the most important cost components for the two strategies. Fuel for cold chain took a non-negligible part of RI total cost (4.03%) because 83% of refrigerators were working with kerosene. Cost structures were disproportionate as social mobilization and trainings were not financed during RI contrarily to SIA. In comparison with no intervention, the two strategies combined permitted to avoid 12,671 measles cases or 19,023 DALYs. The benefit of SIA was 5601 measles cases averted and 6955 additional DALYs averted. Cost per vaccinated child for SIA (442 FCFA) was lower than for RI (1242 FCFA), in line with previous data from the literature. Cost per DALY averted was 2271 FCFA (4.73USD) for SIA and 769 FCFA (1.60USD) for RI. Analysis showed that low vaccine efficacy decreased the cost-effectiveness ratios for the two strategies. SIA was more cost-effective when the proportion of previously unvaccinated children was higher. For the two strategies, costs per DALY were more likely to vary with measles case fatality ratio. Conclusions: SIA is costlier than RI. Both SIA and RI for measles are cost-effective interventions to improve health in Benin compared to no vaccination. Policy makers could make RI more efficient if sufficient funds were allocated to communications activities and to staff motivation (trainings, salaries).