SUGGESTIONS ON HOW TO AVOID THE IMMUNITY TRAP
Inherent in a strategy which requires repeated application of temporary control methods, is the specter of the Immunity Trap. After several years of suppressing malaria transmission by temporary methods, if the methods are suspended for any reason, the previously protected population will be extremely vulnerable to acute disease and death because they will have lost their immunity. The longer the temporary methods are used, the greater will be the risk for the population to fall into the Immunity Trap.
This experience has been clearly documented in Sudan and other African countries. The long history of this problem was described in Webb’s 2014 book, ‘The long struggle against malaria in tropical Africa’.
The way to avoid the Immunity Trap is to add permanent control methods so that if funding or operations are suspended, the permanent methods will reduce the malaria rebound. Such permanent methods include agricultural land reclamation of anopheline breeding sites, housing improvements with screens, and urban drainage, as well as attacking larvae with the microbial bit recently demonstrated in Dar es Salaam.