OBJECTIVE: To evaluate the cost-effectiveness of presumptive vaccination versus serological testing of school-age children (6 to 12 years) and adolescents (13 to 17 years) with a negative or uncertain history of varicella. DESIGN: Decision analysis model based on published and unpublished probabilities and costs. PATIENTS: Hypothetical cohorts of 10,000 school-age children and 10,000 adolescents. MAIN OUTCOME MEASURES: Number of chicken pox cases prevented and cost per chicken pox case prevented. RESULTS: For school-age children, presumptively vaccinating would prevent 95% of the predicted chicken pox cases, would result in net savings when long-term and work loss costs were included, and would have a similar cost per case prevented as routinely testing before vaccination. For adolescents, presumptively vaccinating would be the most effective policy, and would prevent 99% of the projected chicken pox cases. A policy of routinely testing before vaccination would be the least effective policy for adolescents, preventing 81% of the predicted cases. However, even when long-term and work loss costs were taken into account, presumptively vaccinating adolescents had a relatively high cost of $329 per chicken pox case prevented and extremely high incremental costs per chicken pox case prevented compared with policies that involved serological testing. Results for school-age children were sensitive to the probability of previously having had chicken pox given a negative or uncertain history, to the rate of adherence to follow-up visits, and to vaccine price and test price. Results for adolescents were sensitive only to the rate of adherence to the first follow-up visit. CONCLUSIONS: Presumptively vaccinating all patients with a negative or uncertain history of varicella is projected to be a relatively cost-effective policy for school-age children but not for adolescents. However, further empirical studies of the accuracy of a negative or uncertain history of chicken pox in these age groups are needed.
OBJECTIVE: To evaluate the cost-effectiveness of presumptive vaccination versus serological testing of school-age children (6 to 12 years) and adolescents (13 to 17 years) with a negative or uncertain history of varicella. DESIGN: Decision analysis model based on published and unpublished probabilities and costs. PATIENTS: Hypothetical cohorts of 10,000 school-age children and 10,000 adolescents. MAIN OUTCOME MEASURES: Number of chicken pox cases prevented and cost per chicken pox case prevented. RESULTS: For school-age children, presumptively vaccinating would prevent 95% of the predicted chicken pox cases, would result in net savings when long-term and work loss costs were included, and would have a similar cost per case prevented as routinely testing before vaccination. For adolescents, presumptively vaccinating would be the most effective policy, and would prevent 99% of the projected chicken pox cases. A policy of routinely testing before vaccination would be the least effective policy for adolescents, preventing 81% of the predicted cases. However, even when long-term and work loss costs were taken into account, presumptively vaccinating adolescents had a relatively high cost of $329 per chicken pox case prevented and extremely high incremental costs per chicken pox case prevented compared with policies that involved serological testing. Results for school-age children were sensitive to the probability of previously having had chicken pox given a negative or uncertain history, to the rate of adherence to follow-up visits, and to vaccine price and test price. Results for adolescents were sensitive only to the rate of adherence to the first follow-up visit. CONCLUSIONS: Presumptively vaccinating all patients with a negative or uncertain history of varicella is projected to be a relatively cost-effective policy for school-age children but not for adolescents. However, further empirical studies of the accuracy of a negative or uncertain history of chicken pox in these age groups are needed.