Comparing Post-MDA Coverage Survey Data for Trachoma, Onchocerciasis and Lymphatic Filariasis with Reported Data Among 14 District Councils in Tanzania
All councils of Tanzania are endemic with at least two of the five preventive chemotherapy (PC) neglected tropical diseases (NTDs). Mass drug administration (MDA) interventions in Tanzania have interrupted transmission of lymphatic filariasis (LF) in 105 out of 120 councils and trachoma in 65 out of 71 councils. Reported epidemiological coverage by community drug distributors (CDDs) from these councils has historically been high (?80%), however they fail at least one disease-specific assessment (DSA). In October 2019, the Tanzania NTD Control Program (NTDCP) conducted a post-MDA coverage evaluation survey (CES) in 14 councils. The purpose was to compare reported coverage data from CDDs and the data collected from the study to estimate concordance between the two datasets and, second, to identify reasons for non-participation in MDA. The CES was a cross-sectional survey following World Health Organization (WHO) guidelines using probability sampling with segmentation (PSS). According to the following criteria, councils were sampled: 1) failure of DSA at least once for LF and Trachoma and 2) change of MDA strategy for Onchocerciasis. In two out of 14 councils (14.2%), there was higher coverage in the CES results when compared to the one reported by CDDs (81.8% vs. 70.1% and 78.8% vs. 71%). For trachoma, only one council had coverage greater than 80%, and for LF, all the councils had coverage greater than 65%. This contradicts previously reported MDA coverage reported by CDDs that stated that all councils achieved the recommended MDA coverage, except for two councils. The CES also revealed that absenteeism was the main reason people did not participate in MDA (38.1% for trachoma and 36.3% for LF). A secondary reason was that drug distributors did not arrive (22.4% for trachoma and 16.7% for LF). The Tanzania NTDCP will implement new strategies such as strengthening advocacy and social mobilization. It will improve CDD training based on the CES results in councils with low MDA coverage validated by the CES to improve coverage and subsequently work to eliminate NTDs countrywide.
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