Preschool age participation in mass drug administration: Analyzing the impact on community-wide schistosomiasis...

Schistosome infection in childhood is common and can lead to morbidity. A formulation of praziquantel to treat preschool-aged children (PSAC) has been developed recently. This paper assesses the impact of including PSAC in mass drug administration (MDA) on transmission and morbidity at a community-wide level.

We used a model of schistosome transmission to simulate the probability of a community reaching elimination as a public health problem (EPHP) and the reduction in morbidity of children resulting from infections until the age of 5 years, measured by a "worm years" metric as a score of morbidity.

Including PSAC in MDA will almost always lead to a reduction in morbidity. However, it does not necessarily result in a substantial increase in the probability of EPHP. The proportion of schistosome infections in each age group is a key factor in determining the effectiveness of MDA programs, which prioritize different age groups for treatment.

Policymakers should be aware that including PSAC in MDA may not help to reach the World Health Organization target of EPHP. However, a reduction in the average summed worm infection burden at the age children typically start attending school is highly desirable in increasing the long-term benefit of MDA in early childhood.