ABSTRACT
At high levels of transmission there have been concerns that reducing transmission could result in a rebound in mortality in older age groups as the population level of immunity re aligns to new levels of exposure. It has been argued that high rates of infection in early life may stimulate active immunity at a time when other mechanisms such as maternally acquired anti bodies and the persistence of foetal haemoglobin reduce the risk of severe disease.4 Other age-dependent effects may also operate, particularly that cerebral manifestations of malaria are relatively more common among older children than infants. These concerns were first raised in the context of the WHO campaign for the eradication of malaria in the 1950s5,6 and have resurfaced with the growing use of insecticide treated nets (ITNs).4
