Truscott J.E., Hardwick R.J., Werkman M., Kaliappan Saravanakumar P., Manuel M., Ajjampur S.S.R., Asbjörnsdóttir K.H., Khumbo K., Witek-McManus S., Simwanza J., Cottrell Gilles, Houngbégnon P., Ibikounlé M., Walson J.L., Anderson R.M. (2021). Forecasting the effectiveness of the DeWorm3 trial interrupting the transmission of soil-transmitted helminths in three study sites in Benin, India and Malawi. Parasites and Vectors, 14 (1), 67 [13 p.]. ISSN 1756-3305.
Titre du document
Forecasting the effectiveness of the DeWorm3 trial interrupting the transmission of soil-transmitted helminths in three study sites in Benin, India and Malawi
Année de publication
2021
Auteurs
Truscott J.E., Hardwick R.J., Werkman M., Kaliappan Saravanakumar P., Manuel M., Ajjampur S.S.R., Asbjörnsdóttir K.H., Khumbo K., Witek-McManus S., Simwanza J., Cottrell Gilles, Houngbégnon P., Ibikounlé M., Walson J.L., Anderson R.M.
Source
Parasites and Vectors, 2021,
14 (1), 67 [13 p.] ISSN 1756-3305
Background: The DeWorm3 project is an ongoing cluster-randomised trial assessing the feasibility of interrupting
the transmission of soil-transmitted helminths (STH) through mass drug administration (MDA) using study sites in
India, Malawi and Benin. In this article, we describe an approach which uses a combination of statistical and mathematical
methods to forecast the outcome of the trial with respect to its stated goal of reducing the prevalence of
infection to below 2%.
Methods: Our approach is first to define the local patterns of transmission within each study site, which is achieved
by statistical inference of key epidemiological parameters using the baseline epidemiological measures of age-related
prevalence and intensity of STH infection which have been collected by the DeWorm3 trials team. We use these
inferred parameters to calibrate an individual-based stochastic simulation of the trial at the cluster and study site level,
which is subsequently run to forecast the future prevalence of STH infections. The simulator takes into account both
the uncertainties in parameter estimation and the variability inherent in epidemiological and demographic processes
in the simulator. We interpret the forecast results from our simulation with reference to the stated goal of the
DeWorm3 trial, to achieve a target of 2% prevalence at a point 24 months post-cessation of MDA.
Results: Simulated output predicts that the two arms will be distinguishable from each other in all three country
sites at the study end point. In India and Malawi, measured prevalence in the intervention arm is below the threshold
with a high probability (90% and 95%, respectively), but in Benin the heterogeneity between clusters prevents
the arm prevalence from being reduced below the threshold value. At the level of individual study arms within each
site, heterogeneity among clusters leads to a very low probability of achieving complete elimination in an intervention
arm, yielding a post-study scenario with widespread elimination but a few ?hot spot' areas of persisting STH
transmission.
Plan de classement
Santé : généralités [050]
;
Entomologie médicale / Parasitologie / Virologie [052]
;
Biologie du sol [074]
Localisation
Fonds IRD [F B010080269]
Identifiant IRD
fdi:010080269
