1.3 MDA and transmission blocking vaccines Apart from the direct benefit of MDA as a malaria control tool, the proposed study has a scientific objective to determine the suitability of several evaluation tools for a transmission blocking vaccine (TBV). TBV work by inducing antibodies that react with parasite surface antigens in the mosquito midgut after a blood meal. These immune responses suppress the infectivity to mosquitoes and can therefore potentially prevent transmission. Although several groups work on the production of a TBV, there is no experience with the evaluation of such a vaccine in the field. The evaluation of a TBV is rather different of the evaluation of a conventional vaccine which protects the vaccinated individual directly. A TBV doesn't protect the vaccinated individual but the community and has therefore to be evaluated on the community level. Limited available data regarding the protection of communities comes from studies on insecticide treated bed nets.