Fig 1.
Illustration of household-based strategy.
Figure depicts households in two neighbouring villages; household with antigen-positive members are outlined in red, whereas those free from LF have a black outline. The team is currently in the village on the left and tests a proportion of all households. Households that accept testing are shown with solid fill– black if there is no antigen positive members or red if there is an antigen positive household member. If the team identifies a household with an antigen-positive member, the team will offer treatment to members of all households within a given radius around the positive household, except to members of households that recently tested negative or had refused a test. This treatment radius is marked in red. As shown in the diagram, teams will offer treatment to members of households in neighbouring villages that are within the treatment radius of a LF-positive household.
Table 1.
Parameters used for the household-based intervention approach.
Fig 2.
Summary of all simulated surveillance strategies.
^ The five-team household-based strategy was not simulated with the 1km treatment radius. *The household-based strategy where only a single member of each household was offered testing was not simulated with one-team.
Fig 3.
Annual territory-wide antigen prevalence for school-based and workplace-based interventions.
Territory-wide antigen prevalence in the synthetic American Samoan population following three rounds of 3D-MDA in 2018, 2019, and 2021, followed by five rounds of targeted strategies. (A) school-based intervention that tests three different age groups of children (TAS-aged children (ages 6–7 years), elementary school aged children (ages 6–13 years), and all school aged children (ages 6–17 years)) and treats antigen-positive children and members of their household. (B) workplace-based intervention that tests workplaces with 50+ workers or 5+ works and either treats antigen-positive workers or the antigen-positive worker and members of their household. 1% antigen prevalence is shown by the red horizontal dashed line in both plots.
Table 2.
The effectiveness of additional rounds of annual 3D-MDA starting in 2023 for three different levels of treatment coverage.
A strategy’s effectiveness is judged by its control probability, the proportion of simulations in which mf prevalence decreased between 2030 and 2035. Treatments are the average number of treatments administered over the duration of MDA and do not include treatment numbers from the prior MDA rounds in 2018, 2019, and 2021. The uncertainty in the control probabilities is quantified with a 95% credible interval.
Table 3.
The effectiveness of the household-based strategy, with different number of teams, treatment radii, and household test aims (HTA).
A strategy’s effectiveness is judged by its control probability, the proportion of simulations in which mf prevalence decreased between 2030 and 2035. Treatments are the average number of treatments administered over the duration of the strategy and do not include treatment numbers from the prior MDA rounds in 2018, 2019, and 2021. The uncertainty in the control probabilities is quantified with a 95% credible interval.
Fig 4.
LF control probability vs number treatments and tests for community-wide triple-drug MDA and household-based strategies.
Control probability was the proportion of simulations in which mf prevalence decreased from 2030 to 2035 and the household-based strategies offered testing to either 25% or 50% of households (HTA). (A) Control probability as a function of the average number of treatments per strategy. (B) Control probability as a function of the average number of tests and treatments per strategy.