The transmission rate of hepatitis B from mother to child during the perinatal period is extremely high. But, effective treatment of infants born to HBsAg positive mothers consisting of hepatitis B immune globulin and hepatitis B vaccine reduces the carrier state of the infant by 85% to 95%. Women at high risk for hepatitis B include women of Asian or Pacific Island descent, women born in Haiti or sub-Saharan Africa, as well as intravenous drug users. The standard regimen to prevent carrier state in a child born to a HBsAg positive mother consists of the administration of hepatitis B immune globulin at birth and 3 doses of hepatitis B vaccine given at 1, 6, and 18 months of age. A prospective cohort study was implemented to evaluate completion of the 3-stage vaccine regimen required for infants. New York City Department of Health field workers identified 1030 HBsAg positive pregnant women from hospital laboratory log during July 1987 to June 1988. From among 1030 women, 830 women participated and delivered 832 infants.

Completion of the 3 vaccine doses varied by maternal race, maternal birthplace, and health insurance coverage. Infants of Black and Hispanic women were 24% and 37% respectively less likely to complete the series than were infants of Asian women. Infants of women who were Medicaid recipients were 27% less likely to complete the series than were infants covered by private health insurance. Surprisingly, infants without any health coverage were only 4% less likely to complete the vaccine series than were infants covered by private health insurance. To evaluate whether heath insurance status acted as a confounder for observed racial differences, vaccine completion rates by maternal race were stratified by health insurance coverage. Vaccine completion rates by race among women with private insurance or on Medicaid were comparable. In contrast, among uninsured category, Blacks and Hispanics were 32% and 52% less likely to complete the series than Asians. The authors estimate that among the 493 infants who completed the series of vaccines, 174 cases of chronic hepatitis B infections would have occurred had they not received the vaccination, and that the vaccination prevented 160 cases. Nevertheless, this calculation is misleading since it does not consider the entire initial study population. Thus, actually 832 infants must complete the 3 vaccine doses to prevent 160 chronic cases of hepatitis B. Although the vaccine regimen is approximately 92 % effective, in reality (with respect to public health implications) it is 20% effective.

Health insurance status accounts for most of the differences in vaccine completion rates. Medicaid insured infants, which combines all racial groups, and also uninsured Blacks and Hispanics infants had very low completion rates. Inadequate Medicaid reimbursement may act as a barrier to physicians treating infants that require hepatitis B vaccines. The racial differences among the uninsured may reflect socioeconomic status. More than 95% of the Asian and white uninsured women delivered at private hospitals, while most of the Black and Hispanic uninsured women delivered at public hospitals. The hospital may indicate the socioeconomic status of its patient population. Thus, these Asian and white uninsured women may be in a higher socioeconomic group than the Black and Hispanic uninsured women. The study discloses that the major barrier to completion of the hepatitis B vaccine was financial, involving both health insurance coverage and the socioeconomic status. The authors seem to attribute the observed racial differences exclusively to financial considerations. However, among the women without private health insurance, uninsured and Medicaid covered Hispanic women were 38% and 22% respectively less likely to complete the series than were uninsured and Medicaid covered Blacks. Thus, non-financial barriers may also have been present.