Integrated strategies incorporating health education to control Soil-transmitted Helminthiases in schoolchildren in the Philippines

Abstract

Soil-transmitted helminths (STH) are intestinal worms causing disease and morbidity globally. Mass drug administration (MDA) of antihelminthic drugs to at-risk populations is still the main strategy for control. However, MDA, as a stand-alone intervention, does not prevent reinfection. Thus, complementary approaches such as improvements in water, sanitation and hygiene (WASH) infrastructure and hygiene education are needed for sustainable control. The main aim of this PhD thesis is to determine the effectiveness and generalizability of the video based health education package, "The Magic Glasses" (for use in schools), culturally adapted for the Philippines, on STH infections in Laguna province. Having previously shown the positive impact of this intervention in increasing knowledge, improving behaviour and preventing STH infections among Chinese schoolchildren, a new cluster randomised controlled trial (RCT) was conducted in another Asian country highly endemic for STH. Results of the new RCT showed that "The Magic Glasses" has led to a statistically significant modest improvement in STH knowledge and behaviour among Filipino schoolchildren. The primary analysis demonstrated no reduction in overall STH infections, however, sub-group analysis revealed reduction of infections in intervention schools where the baseline prevalence did not exceed 15%. Its impact in preventing STH infections in schools with 15% or less endemic prevalence suggests that in low transmission areas, health education and MDA can reduce infection whereas MDA alone will not. However, in areas with higher prevalence, the health educational package including high levels of MDA coverage and improved WASH infrastructure and services will be necessary. The narrative review presented in thesis further highlights the importance of integrated strategies in the control of STH infections in the Philippines. Findings of this review showed persistently high STH prevalence despite several years of MDA implementation in the Philippines. Using the baseline data from the RCT, the STH prevalence, risk factors associated with infection, and the impact of STH on nutritional indices among schoolchildren were also explored. Results showed high STH prevalence with age, socio-economic status, rural/urban classification of schools and knowledge of STH as significant risk factors for STH. Infections with any STH were significantly associated with stunting and being underweight but not wasting or anaemia after controlling for confounding covariates. Finally, this thesis determined the costs of the intervention in the context of the trial itself and scaled up as part of the national STH control program in the Philippines at the regional and national level. The cost per student to deliver nationally was estimated at only USD 0.34. This is in comparison to the delivery of standard health education (SHE) and MDA which were costed at USD 2.30 and USD 1.14 per student, respectively. The additional cost of including the intervention into the national STH control program is therefore minimal with only 9.9% increase to the cost of the program. The findings presented in this thesis provide further evidence of the applicability, affordability and scalability of "The Magic Glasses" for the Philippine authorities to consider an integrated control program including health education, at a minimal additional cost, to target the burden of STH in schoolchildren.