Single-dose albendazole falters against whipworm in persistent Kenyan transmission foci

Single-dose albendazole, the workhorse of Kenya’s school-based deworming programme, performed strongly against roundworm but fell short against whipworm in three counties where intestinal worm infections have stubbornly persisted despite seven rounds of annual mass drug administration, according to a prospective longitudinal study conducted among primary school children in Kisii, Narok and Vihiga Counties between March and July 2019.

The research, carried out by investigators at the Kenya Medical Research Institute, set out to determine the programmatic effectiveness of albendazole among school-age children attending primary schools in counties that have participated in the National School-Based Deworming Programme since 2012. Soil-transmitted helminthiasis is targeted for elimination as a public health problem by 2030 under the Kenya Master Plan for neglected tropical diseases covering 2023 to 2027 and the Kenya health policy spanning 2014 to 2030, with preventive chemotherapy through mass drug administration remaining the primary control strategy.

The study counties were not chosen at random. Kisii, Narok and Vihiga were purposively selected because they showed sustained high infection prevalence above 30 percent, or a low relative reduction in prevalence below 50 percent, in the 2018 national evaluation survey. Within them, primary schools with historical prevalence exceeding 30 percent were sampled, and children were screened using the Kato-Katz technique at baseline. From that screening, 573 baseline-positive children were enrolled and monitored across three sequential post-treatment follow-up rounds, allowing the team to track how well the drug performed not just once but repeatedly over a season of continued environmental exposure.

Cure rates and egg reduction rates were evaluated against baseline using weighted Poisson regression models with robust variance estimation, with non-linear parameter transformations and 95 percent confidence intervals derived using the delta method.

At the first follow-up, albendazole demonstrated high effectiveness against Ascaris lumbricoides, the giant roundworm. The drug achieved a cure rate of 94.80 percent, with a 95 percent confidence interval of 92.61 to 97.00 percent, and an egg reduction rate of 95.54 percent, with a 95 percent confidence interval of 92.36 to 98.71 percent. That egg reduction figure surpassed the World Health Organization performance benchmark of at least 95 percent, confirming that in these persistent foci the drug retained robust initial punch against roundworm even after years of repeated deployment.

Against Trichuris trichiura, the whipworm, the picture was markedly less encouraging. The cure rate was 65.41 percent, with a 95 percent confidence interval of 56.49 to 74.34 percent, and the egg reduction rate was 53.79 percent, with a 95 percent confidence interval of 15.95 to 91.62 percent. Lower egg reductions were observed in specific subgroups, and the whipworm response failed to meet the threshold, marking a sub-optimal result with subgroup variations. For hookworm, the initial cure rate was 76.74 percent, with a 95 percent confidence interval of 26.84 to 126.63 percent, and the egg reduction rate was 99.40 percent, with a 95 percent confidence interval of 97.89 to 100.90 percent.

The story did not end at the first follow-up. Over subsequent monitoring rounds, cure rates and egg reduction rates fluctuated, a pattern the researchers attribute to local environmental re-exposure and transmission dynamics.

The authors conclude that single-dose albendazole demonstrated high initial effectiveness against Ascaris lumbricoides at the first follow-up, meeting the World Health Organization egg reduction threshold of at least 95 percent. However, observed treatment effectiveness fluctuated across subsequent survey rounds without re-treatment, and Trichuris trichiura exhibited a sub-optimal response with subgroup variations that failed to meet the threshold. Overall, while single-dose albendazole maintains robust effectiveness against roundworm, its localized programmatic effectiveness against whipworm remains limited in these persistent transmission foci.

The study, published in Frontiers in Tropical Diseases, was received on 2 July 2026 and accepted on 9 October 2026, and its authors note that all claims expressed in the article are solely those of the authors and do not necessarily represent those of their affiliated organizations or the publisher.

Subject of Research: Programmatic effectiveness of single-dose albendazole against soil-transmitted helminthiasis in Kenyan school-age children after seven rounds of annual mass drug administration.

Article Title: Assessment of the programmatic effectiveness of single-dose albendazole against soil-transmitted helminthiasis in school-age children following seven rounds of annual mass drug administration in selected counties of Kenya

Article References: Okoyo, C., Chepchieng, G., Kemunto, E., Araka, S., Masaku, J., Njenga, S. M., & Mwandawiro, C. (2026). Assessment of the programmatic effectiveness of single-dose albendazole against soil-transmitted helminthiasis in school-age children following seven rounds of annual mass drug administration in selected counties of Kenya. Frontiers in Tropical Diseases, 7, Article 1926584. https://doi.org/10.3389/fitd.2026.1926584

Image Credits: AI Generated

DOI: 10.3389/fitd.2026.1926584

Keywords: albendazole, soil-transmitted helminthiasis, mass drug administration, Kenya, school-age children, cure rate, egg reduction rate, neglected tropical diseases, Kato-Katz, deworming, Assessment, programmatic