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Table 2 Key decisions related to design of the gaining and sustaining control of schistosomiasis studies, and their rationale

From: Gaining and sustaining schistosomiasis control: study protocol and baseline data prior to different treatment strategies in five African countries

Decision Rationale
The study arms would not necessarily align with WHO recommendations for PCT The WHO recommendations are not solidly evidence-based, and studying them would not answer most pressing questions
Sustaining schistosomiasis control studies would only involve SBT, and not adults or CWT Existing data indicate adults are not major sources of transmission when prevalence of infection is <25 %, making testing and interventions for adults not cost-effective when resources are limited
Sustaining and gaining control of schistosomiasis studies would involve places with prevalence 10–24 % and ≥25 % in children aged 9–12 year, respectively The cutoff of 10 % for sustaining studies was based on the idea that below that, one is moving towards elimination, and this will require additional interventions besides PCT. The choice of 25 % prevalence to divide gaining and sustaining studies was based on expert opinion
Sustaining control of schistosomiasis studies would include three arms, gaining studies would have six arms SCORE would have preferred to test many more combinations of interventions, however this was not practical. The numbers of arms, numbers of villages per arm and number of children per village were an attempt to balance scientific, resource-related and practical considerations
Children aged 13–14 years would be tested to determine eligibility of a village for the sustaining or gaining control of schistosomiasis studies Children who test positive must be treated. Testing children aged 9–12 years and treating those infected could affect the year 1 and subsequent study results, especially if prevalence is high. A very high prevalence could necessitate treating the entire village
“Drug holidays” would be included in study arms The cost and impact of “drug holidays” is not known. If holidays have minimal negative effects on prevalence and intensity of Schistosoma infection in villages that have been targetted by PCT, holidays could allow for more widespread treatment
In all studies, first-year students would be tested at the beginning and end of the study First-year students provide a measure of new infections in the community. If transmission is decreasing, prevalence and intensity in these children should fall
A convenience sample of adults would be tested in gaining control of schistosomiasis studies Although initial plans called for a more systematic approach to identifying adults for testing, this proved impractical given the resources, so convenience samples were allowed
SCORE would provide mobile data collection software Information provided at the harmonization meeting indicated that the software being used in lymphatic filariasis research could be readily adapted for SCORE use. This turned out not to be the case, but SCORE’s commitment to standardising data collection, providing support for data cleaning and storage and supporting mobile technology remained
SCORE-supported research needed to be conducted in close collaboration with Ministries of Health and Education This was deemed essential both to ensure that PCT in SCORE study areas were conducted per protocol and to encourage the Ministries to use the results. In addition, it was assumed that PZQ access and use would work best when coordinated with the national schistosomiasis control programme
Study villages would need to achieve high levels of coverage; if these were not achieved during PCT, a team would need to return to the village to provide additional treatment It was recognised that high coverage levels are not always achieved by PCT programmes. However, comparison of effectiveness among arms would require that treatments be delivered and actually consumed. Investigators were encouraged to have treatments directly observed to assure compliance
Investigators would be encouraged to publish their countries’ results; the SCORE secretariat would take responsibility for publishing combined results In addition to encouraging widespread dissemination of the results of research, data sharing approaches that would allow investigators to use the data for modelling and other purposes were to be developed
  1. CWT community-wide treatment, PCT preventive chemotherapy, PZQ praziquantel, SBT school-based treatment, SCORE schistosomiasis consortium for operational research and evaluation, WHO World Health Organization