Demonstrating the impact of the new vaccine will encourage other countries to introduce it.
Measuring impact will allow MVP to evaluate its goals and strategy
The definition of success for the Meningitis Vaccine Project is the elimination of epidemic meningitis in sub-Saharan countries that introduce the meningococcal A conjugate vaccine. Although it is estimated that it will take about a decade to eliminate the disease (the time it will take to conduct mass vaccination campaigns throughout the meningitis belt), MVP has developed a postintroduction evaluation plan to assess the impact of the introduction of MenAfriVac® in the first introduction countries.
Evaluating the impact of mass vaccination
Measuring the impact of the first mass vaccination campaigns is essential— for scientific reasons, to show that the new meningococcal A conjugate vaccine works as expected; for economic reasons, to show that introduction of the new conjugate vaccine is a money-saving intervention compared to costly emergency vaccination campaign; and for advocacy reasons, because the best argument for additional funding is to show that the funds given for the first introductions have been effectively used, both in terms of reaching the target population and reducing group A meningococcal disease burden in the targeted countries. Showing impact is also a powerful advocacy tool to encourage other meningitis belt countries to introduce the vaccine expeditiously.
Principal evaluation goals include the following:
- Accurate assessment of vaccination coverage.
- Comprehensive plan to monitor Adverse Events Following Immunization (AEFI).
- Case-based meningitis surveillance before and after introduction.
- Effect of vaccine introduction on carriage of group A and other meningococci.
Since strong laboratory-surveillance is essential for detecting and confirming meningococcal disease cases and for evaluating the effectiveness of MenAfriVac®, disease surveillance and laboratory capabilities have been reinforced in Burkina Faso, Mali, and Niger, the first three introduction countries. Continued investment in these infrastructures is essential to ensure that the information necessary to determine vaccine effectiveness will be available.
Monitoring at country level will be carried out by country-based surveillance units with technical support from WHO, UNICEF, and other partners, including the London School of Hygiene and Tropical Medicine, who is in charge of conducting a series of carriage studies to evaluate the impact of MenAfriVac® on the transmission of meningococcal infection in countries of the African meningitis belt.
Impact on health systems and economies
A socioeconomic impact study estimated the expected health outcomes, treatment costs, vaccination costs, and cost-effectiveness of vaccination in the hyperendemic countries over a six-year-period.1 The analysis compared the costs and results anticipated after the introduction of MenAfriVac® against the current strategy of reactive vaccinations with polysaccharide vaccine. The comparison predicted that the introduction of MenAfriVac® is a cost-savings intervention (US$192 saved per disability-adjusted life year [DALY] averted). Two important characteristics of the new meningococcal A conjugate vaccine account for the savings: (1) MenAfriVac® is likely to result in herd immunity, a benefit not seen with polysaccharide vaccines and (2) MenAfriVac® is priced at less than one half the cost of the polysaccharide vaccine.
1. World Health Organization and UNICEF. Eliminating serogroup A meningococcal meningitis epidemics as a public health problem in Africa. An investment case for the GAVI Alliance. 15 May 2008.
Photo: Monique Berlier.