Cost of standard indoor ultra‐low‐volume space spraying as a method to control adult dengue vectors

Objectives To access the costs of standard indoor ultra‐low‐volume (SID‐ULV) space spraying for controlling dengue vectors in Thailand. Methods Resources related to SID‐ULV space spraying as a method to control dengue vectors between July and December 2009 were identified, measured and valued taking a societal perspective into consideration. Information on costs was collected from direct observations, interviews and bookkeeping records. Uncertainty of unit costs was investigated using a bootstrap technique. Results Costs of SID‐ULV were calculated from 18 new dengue cases that covered 1492 surrounding houses. The average coverage of the SID‐ULV was 64.4%. In the first round of spraying, 53% of target houses were sprayed and 44.6% in the second round, of which 69.2% and 54.7% received entire indoor space spraying. Unit costs per case, per 10 houses and per 100 m² were USD 705 (95% Confidence Interval CI, 539–888), 180 (95% CI, 150–212) and USD 23 (95% CI, 17–30). The majority of SID‐ULV unit cost per case was attributed to productivity loss (83.9%) and recurrent costs (15.2%). The unit cost of the SID‐ULV per case and per house in rural was 2.8 and 1.6 times lower than municipal area. The estimated annual cost of SID‐ULV space spraying from 2005 to 2009 using healthcare perspective ranged from USD 5.3 to 10.3 million. Conclusions The majority of the cost of SID‐ULV space spraying was attributed to productivity loss. Potential productivity loss influences the achievement of high coverage, so well‐planned SID‐ULV space spraying strategies are needed to reduce costs.