Estimated Annual Perinatal Hepatitis B Virus Infections in the United States, 2000-2009
Ninety percent of perinatal hepatitis B virus (HBV) infections result in chronic HBV (CHBV), which carries 25% risk of premature death from progressive liver injury, cirrhosis, and liver cancer. In 1990, the Centers for Disease Control and Prevention (CDC) funded Perinatal Hepatitis B Prevention Programs (PHBPP) to ensure postexposure prophylaxis for exposed infants and accelerate elimination of perinatal CHBV in the United States. From 2000 to 2009, the annual rates of perinatal CHBV reported by PHBPP (0.8%-2.4%) were consistently lower than expected rates from CDC models (3.0%-4.1%), suggesting that rates of CHBV might be higher among infants whose outcomes were not identified by PHBPP. To better understand the factors impacting modeled expected number and rates of perinatal CHBV, we examined historic CDC models, applied updated inputs to the 2009 CDC model, and performed sensitivity analyses over a range of parameter values.
Models employed estimates of the annual number of births to hepatitis B surface antigen (HBsAg)-positive pregnant women, and data from PHBPP and National Immunization Surveys. Published literature provided prenatal HBsAg screening rates, efficacy of postexposure prophylaxis (PEP), and perinatal HBV transmission rates.
The updated 2009 model predicted 952 perinatal CHBV infections, equivalent to a baseline rate of 3.84%, among infants of HBsAg-positive women. Sensitivity analyses yielded a possible range of perinatal CHBV rates between 0.60% and 15.41%. The proportion of infants receiving timely PEP, the efficacy of PEP, and perinatal HBV transmission rate were major "drivers" of CHBV rates. Three-way sensitivity analysis yielded possible perinatal CHBV rates between 0.79% and 13.64%.
Modeling provided useful programmatic goals for achieving elimination of perinatal CHBV in the United States. Limitations of data inputs likely contributed to discrepancies between predicted and reported rates.