Economic Burden of West Nile Virus Disease

Quebec, Canada, 2012-2013

Najwa Ouhoummane; Eric Tchouaket; Anne-Marie Lowe; Ann Fortin; Dahlia Kairy; Anne Vibien; Jessica Kovitz-Lensch; Terry-Nan Tannenbaum; François Milord


Emerging Infectious Diseases. 2019;25(10):1943-1950. 

In This Article


Of the 155 symptomatic WNV patients during 2012–2013, a total of 93 (60%) agreed to participate in the study, but 2 of them could not be reached for the telephone interview and 1 with missing information about clinical syndrome was excluded from analyses. Medical records were available for 81 (87%) patients (71 hospitalizatons and 10 emergency department visits). Participants and nonparticipants were comparable with regard to demographics (except for sex; more women agreed to participate [54% vs. 36%; p = 0.026]) and illness severity (hospitalization, clinical syndrome, and death).

Demographic and Clinical Characteristics

We obtained demographic and clinical characteristics of patients (Table 3). For 90 patients, WNF accounted for 27%, WNM 20%, and WNE 53%. Patients with WNE were significantly older than patients with WNM or WNF; 71% of WNE patients were ≥60 years of age compared with 22% of WNM patients and 29% of WNF patients (p<0.0001). Most patients with neurologic syndrome were hospitalized. The median hospital stay was longer for WNE patients than for WNM patients (p<0.0001) or WNF patients (p = 0.010). Ten (21%) WNE patients and 1 (6%) WNM patient died during hospitalization. In addition, 3 WNE patients, 2 who were discharged to home with support and 1 requiring rehabilitation services, died during the follow-up period, but their deaths were not considered to be directly related to WNV infection.

Use of Medical and Paramedical Services and Absence of Work

We obtained data for use of medical and paramedical services up to 2 years after the acute phase of WNV disease (Table 4). When we excluded in-hospital deaths, the most common services used by participants were physician visits (66%), followed by medications (41%) and neurologist visits (26%). In general, WNE and WNM patients used more services and WNM participants needed more physician (p = 0.016) and neurologist (p = 0.029) visits. Six WNE patients were admitted to rehabilitation (median length of stay 75 days, range 30–120 days). Most patients who had a job missed work because of their infection (median absence 60 days, range 5–365 days).

Although 41% of patients reported outpatient medication expenses, they could not accurately recall the names and amounts of medication taken. Therefore, we did not compute medication costs.

Direct and Indirect Costs

We determined direct and indirect costs according to illness severity (Table 5). WNE patients accounted for the largest proportion of total cost (median cost $21,332, IQR $12,131–$28,101) per participant compared with $8,124 (IQR $4,025–$13,631) for WNM patients (p = 0.0004) and $192 (IQR $20–$5,359) for WNF patients (p<0.0001). For WNE patients, costs were attributable mostly to hospitalization, which accounted for 65% of the total cost, followed by inpatient rehabilitation (20%). For WNM patients, indirect costs (47%), followed by hospitalization (38%), contributed to the largest proportion of total costs. For WNF patients, hospitalization (44%) and indirect costs (44%) contributed to the same proportion of total cost. Median indirect costs were significantly higher for WNM patients than for WNE (p = 0.004) or WNF (p = 0.0005) patients. Physician visit costs were also significantly higher for WNM patients than for WNE (p = 0.041) or WNF (p = 0.038) patients.

During 2012, a total of 124 symptomatic WNV patients were reported in the province of Quebec, and during 2013, a total of 31 symptomatic WNV patients were reported. Based on our study, the estimated total cost of these cases was ≈$1.7 million for 2012 and ≈$430,000 for 2012. We determined the estimated total cost by category (Table 6). For both years, WNF accounted for <5% of the total, and WNM accounted <10% of the total and WNE accounted for >85% of extrapolated costs.