Objective: To evaluate economic and clinical outcomes of a program of routine prenatal serotesting for varicella and postpartum vaccination of seronegative women.
Methods: An analytic cost-effectiveness model was constructed to compare the current strategy of no serotesting with 1) selective serotesting of pregnant women without a prior history of chickenpox and 2) serotesting of all pregnant women. In both serotesting strategies, seronegative women were vaccinated postpartum. The model followed a hypothetical cohort of 4 million women over 20 years. Costs and chickenpox disease outcomes during and outside of subsequent pregnancies were considered. The incremental cost-effectiveness (cost per adult chickenpox case prevented) of selective serotesting compared with the current strategy was measured.
Results: Compared to no testing, selective serotesting would prevent 43% (48,577 of 112,654) of adult chickenpox cases, save $21.8 million in discounted medical and work loss costs from the societal perspective, and cost $1126 per case prevented from the health payer's perspective (medical costs only). The model was sensitive to varicella seroprevalence and incidence of chickenpox among susceptible women but was relatively insensitive to the cost of serologic testing and vaccination. Compared with selective serotesting, the serotest-all strategy would prevent an additional 15,645 cases, at a societal cost of $7653 per additional case prevented.
Conclusion: The selective serotesting strategy could prevent nearly half of chickenpox cases among this cohort and is cost-saving from the societal perspective. From the health payer's perspective, it compares favorably with other generally accepted preventive practices. It should be considered for prevention of chickenpox among women of childbearing age.