Background and Context
Measles is a highly communicable infectious disease that is spread through droplets from the nose or throat. Vaccination programs have eliminated indigenous measles in Canada; however, outbreaks continue to occur through importations. Recent outbreaks in Canada and the US have highlighted the importance of immunization for the containment of outbreaks. Contact tracing has been implemented to mitigate the spread of measles by identifying susceptible contacts for treatment and to avoid further spread. The Public Health Agency of Canada (PHAC) is reviewing current activities and exploring new strategies aimed at sustaining measles elimination in Canada, and has requested that CADTH undertake a project estimating the amount of health care resources and costs that should go into contact tracing in response to a case of measles in Canada.
A review of the published literature was undertaken to identify studies that could inform a cost analysis to estimate the health care resource use associated with contact tracing for a measles outbreak.
Seven primary studies and one review reported disaggregated resource use and/or costs associated with contact tracing, although none were from a Canadian perspective. The primary studies reported a wide range of measles cases, contacts, and associated costs and resource use. As such, it was not considered appropriate to generalize the results of any single population to a wider Canadian population. Although limitations with the review by Ortega-Sanchez et al. were noted, it was deemed an appropriate starting point to undertake an analysis of the estimated costs associated with contact tracing.
A cost analysis was undertaken for the Canadian population from the perspective of a Canadian public health unit, in which costs to the public payer associated with the task of contact tracing, excluding costs associated with the direct treatment of case patients, were the focus. Information from a subset of US studies was used to determine a model scenario that estimated costs and health care resources based on the number of contacts and cases, and information regarding Canadian-specific outbreaks was obtained from an informal literature search and PHAC.
In the base-case analysis, an outbreak in Alberta in 2013 (42 cases; 2,005 contacts) was the basis for estimating costs associated with contact tracing activities, which resulted in an estimate of $297,000. Sensitivity analyses adjusting the costs, resource use, and model scenario had a large effect on the total cost associated with contact tracing (range: $76,267 to $2,078,225), with the number of contacts per case having the largest impact.
The estimated cost of contact tracing activities is likely an underestimate, given the lack of information on the type of activities and extent of effort in Canada. Information on contact tracing activities during measles outbreaks is not typically collected in a standardized manner that can be used to inform decision-making. More detailed capture of activities and costs incurred during outbreaks will allow for more precise estimates of the economic impact of contact tracing activities.