An assessment of coverage and adverse events following country-wide triple-therapy mass drug administration for lymphatic filariasis elimination, Samoa 2018

Background The Global Programme to Eliminate Lymphatic Filariasis is making considerable progress but has experienced challenges in meeting targets in some countries. Recent World Health Organization guidelines have recommended two rounds of triple-drug therapy with ivermectin, diethylcarbamazine (DEC), and albendazole (IDA), in areas where mass drug administration (MDA) results with two drugs (DEC and albendazole) have been suboptimal, as is the case in Samoa. In August 2018, Samoa was the first in the world to implement countrywide triple-drug MDA. This paper aims to describe Samoa’s experience with program coverage and adverse events (AEs) in the first round of triple-drug MDA. Methodology/Principal findings We assessed MDA awareness, reach, compliance, coverage and AEs from three different data sources: a Supervisor’s Coverage Tool (SCT) in three villages; a large cross-sectional community survey in September/October 2018, 7-11 weeks after the first round of triple-drug MDA; and AE surveillance conducted by the Ministry of Health, Samoa. Participants aged ≥5 years had a fingerprick blood sample tested for circulating filarial antigen using the Alere Filariasis Test Strip. Data were analysed descriptively. In our sample of 4420 people (2.2% of the population), age-adjusted estimates indicated that 89.0% of the eligible population were offered MDA and 80.2% of the total population took MDA. Mild AEs were reported by 13.3% and moderate/severe AEs by 2.9% of participants. Conclusions/Significance This study following the 2018 triple-drug MDA in Samoa demonstrated a high reported program awareness and reach of 90.8% and 89.0%, respectively. Coverage of 80.2% of the total population showed that MDA was well accepted and well tolerated by the community. Author summary Lymphatic filariasis is a mosquito transmitted worm disease. A global program underway aims to eliminate lymphatic filariasis as a public health problem by distributing deworming drugs to the whole population once a year for at least five years. In some countries, including Samoa, this strategy has not been sufficient to eliminate transmission. A new drug has been added, and in 2018, Samoa was the first country in the world to apply triple drug mass drug administration using ivermectin, diethylcarbamazine, and albendazole. This study reports on the coverage achieved (percentage of people who reported taking the drugs) and adverse events after taking the drugs. Data were obtained from three different sources. A large community survey of over 4000 people, done 7-11 weeks after the distribution of the first round, found that the program reached and offered MDA to approximately 90% of the whole population, and approximately 80% of the whole population swallowed the drugs. Findings from the community survey on participation in the MDA program were consistent with those from the WHO recommended Supervisor’s Coverage Tool, a smaller survey which was undertaken in three villages by the Samoan Ministry of Health. Data on AEs related to MDA were collected during the community survey, and also through a system set up by the Ministry of Health to enable community members to report any problems related to MDA and receive advice on managing problems. There were relatively few adverse events reported and most of them were mild and of short duration. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work received financial support from the Coalition for Operational Research on Neglected Tropical Diseases, which is funded at The Task Force for Global Health primarily by the Bill & Melinda Gates Foundation, by the United States Agency for International Development through its Neglected Tropical Diseases Program, and with UK aid from the British people. CLL was supported by an Australian National Health and Medical Research Council (www.nhmrc.gov.au) Fellowship (1109035). GAW was supported by the Tasmanian Department of Health, the Commonwealth Specialist Training Program, and the Australian National University Master of Applied Epidemiology Program. Other than those included as authors, the funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. ### Author Declarations All relevant ethical guidelines have been followed; any necessary IRB and/or ethics committee approvals have been obtained and details of the IRB/oversight body are included in the manuscript. Yes All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The data used in the present study are available from the corresponding author upon reasonable request. * ADL : activities of daily living AE(s) : adverse event(s) AUA : Apia Urban Area Ag : antigen CI : confidence intervals DA : diethylcarbamazapine [DEC] and albendazole DEC : diethylcarbamazine GPELF : Global Programme to Eliminate Lymphatic Filariasis FTS : filariasis test strip IDA : ivermectin, diethylcarbamazine and albendazole LF : lymphatic filariasis MDA : mass drug administration Mf : microfilariae NWU : Northwest Upolu PacELF : Pacific Programme to Eliminate Lymphatic Filariasis PSU : primary sampling unit ROU : Rest of Upolu SaMELFS : Samoa Surveillance and Monitoring to Eliminate Lymphatic Filariasis and Scabies from Samoa SAV : Savai’i SCT : Supervisor’s Coverage Tool TAS : Transmission Assessment Survey WHO : World Health Organization