Findings from a new study in Zanzibar, published January 23 in PLoS Neglected Tropical Diseases, pave the way for the World Health Organization (WHO) to recommend the mass co-delivery of three anti-parasitic drugs for the first time.
The study shows the safety of delivering three drugs simultaneously – ivermectin, albendazole and praziquantel – in order to tackle three diseases, elephantiasis (lymphatic filariasis), soil-transmitted worms (helminths), and schistosomiasis. Public health interventions based on distribution of these drugs have generally been implemented using one drug at a time. But a coordinated approach could prove to be much more resource- and cost-effective.
“Only through integration will we reduce distribution costs, make the best use of our available human resources and increase community participation and compliance, without any added risk to the population,” said study author Khalfan A. Mohammed, Manager of the new Zanzibar Integrated Helminth Control Programme of the Ministry of Health and Social Welfare.
The study, initiated by the WHO in cooperation with the Ministry of Health and Social Welfare of Zanzibar, United Republic of Tanzania, and the Liverpool School of Tropical Medicine's Lymphatic Filariasis Support Centre, examined the possible side-effects of a triple-drug administration in Zanzibar, United Republic of Tanzania, where several previous treatment rounds with one or two drugs had already taken place.
First, a total of 5055 Zanzibari children and adults living in areas endemic for lymphatic filariasis, soil-transmitted helminthiasis (STH), and schistosomiasis were enrolled in a pilot study. After finding there were no severe adverse events associated with the combined triple-therapy treatment, the researchers scaled up the intervention to make it country wide, treating the entire eligible population of over 700,000 individuals.
Surveillance carried out during both intervention periods showed that the side-effects attributable to the co-delivery of the three drugs were mild and required no medical attention. The data suggest that co-administration of the three drugs is safe in areas where LF, STH and schistosomiasis are co-endemic and populations have received repeated treatments previously.
Although WHO has long recommended the coordinated delivery of drugs to tackle neglected tropical diseases, the maximum number of drugs for simultaneous delivery was limited to two for safety reasons. If the safety of the co-administration of three drugs is confirmed by further studies, WHO is likely to include triple drug administration in its guidelines where appropriate.
“These infections compromise the lives of millions of people,” said Dr Lorenzo Savioli, co-author of the study and Director of the WHO Department of Control of Neglected Tropical Diseases. “This study is a welcome new addition to our existing arsenal of robust, low-cost and effective interventions.”
Professor David H. Molyneux of the Lymphatic Filariasis Support Centre based at the Liverpool School of Tropical Medicine, another co-author of the study, said: “The study shows that we can now offer the appropriate combination of drugs for each combination of helminthic diseases. It also shows the real advantage of working in partnership to generate practical results on the ground.”
The Honourable Sultan M. Mugheiry, Minister of Health and Social Welfare of Zanzibar, who was not a study author, commented: “Zanzibar has been on the frontline of the fight against schistosomiasis, STH and lymphatic filariasis in Africa. We hope these results will help our country but also simplify the treatment for millions of other infected individuals in the poorest parts of the developing world.”