Trachoma programmes undertake impact surveys after a number of rounds of mass drug administration – this helps determine whether additional MDA rounds are recommended before re-survey. Impact survey costs, and the proportion of impact surveys ‘failing’ influence the cost of eliminating trachoma.
The paper looks at the financial cost of undertaking MDA with and without conducting impact surveys, to see when continuing MDA without impact surveys becomes advantageous in financial cost terms. This was modelled and found to be when the (failure rate) continuation rate exceeds 71%. Doing impact surveys often saves money, money that can be redirected to provide MDA in other areas.