Economic Analysis of Prevaccination Serotesting Compared With Presumptive Immunization for Polio, Diphtheria, and Tetanus in Internationally Adopted and Immigrant Infants

Abstract

BACKGROUND. No consensus exists about whether to conduct prevaccination serotesting or to presumptively vaccinate internationally adopted and immigrant infants with inactivated polio (IPV) and diphtheria-tetanus-acellular pertussis (DTaP) immunizations. OBJECTIVE. To study the clinical and economic outcomes from a societal perspective of prevaccination serotesting in a hypothetical 12-month-old internationally adopted or immigrant infant. DESIGN AND METHODS. A decision analysis model was developed comparing presumptive vaccination with IPV versus serotesting for poliovirus type 1, 2, and 3 antibodies followed by vaccination in unprotected patients. A similar decision analysis model was developed comparing presumptive vaccination with DTaP versus serotesting for diphtheria and tetanus toxoid antibodies. The main outcome measures were cost per patient protected from polio, diphtheria, and tetanus. RESULTS. Compared with presumptive immunization, prevaccination serotesting for polio increases the cost per patient from $57 to $62 and decreases the percentage of patients protected against polio from 95.3% to 94.0%. Serotesting for diphtheria and tetanus increases the cost per patient from $62 to $119 and increases the percentage of patients protected against both diphtheria and tetanus from 91.5% to 92.3%. Presumptive immunization with DTaP costs less and is more clinically effective than serotesting if >80% of patients do not complete the full vaccine series or if antibody seroprevalence to both diphtheria and tetanus is <51%. CONCLUSIONS. Presumptive immunization for polio improves outcomes and saves costs compared with prevaccination serotesting in internationally adopted and immigrant infants. The results for DTaP are less definitive, although immunization is the preferred strategy in populations with poor vaccine compliance or low seroprevalence of antibodies to diphtheria and tetanus.