Newborn hepatitis B immunization rates in primary care practices.

OBJECTIVES

To assess the hepatitis B immunization rate and to identify the reasons for an incomplete immunization series in newborns and infants seen in primary care practices.

DESIGN

An inception cohort study enrolling newborns and infants and assessing their hepatitis B immunization status at 9 and 18 months of age.

SETTING

Six primary care offices, most in rural environments.

PATIENTS

All newborns and infants seen at 1 of 6 offices.

INTERVENTION

Infants born between January 1, 1993, and September 30, 1994, were followed up through June 30, 1995. Hepatitis B immunization status and the reasons for an incomplete status were recorded at each visit.

MAIN OUTCOME MEASURES

Hepatitis B immunization rates at 9 and 18 months of age, and the reasons for immunization failure.

RESULTS

The immunization rates of infants aged 9 and 18 months were 60% and 77%, respectively. The most common reasons for inadequate immunization of the 247 infants followed up through age 18 months were patient transfer (7%), failing to return for a scheduled visit (4%), and guardians refusing the immunization (4%). Failure to return for a scheduled visit was the reason for the incomplete immunization in 13% of the 9-month-old infants. Immunization of these patients was the most important factor in the higher immunization rate at 18 months of age. By the age of 18 months, 95% of all infants had received at least 2 doses of the hepatitis B immunization.

CONCLUSIONS

A hepatitis B newborn immunization rate of 77% by age 18 months was achieved in a primary care office setting. Barriers to complete immunization by the age of 18 months include patient transfer, patient failure to return, and parental refusal of immunization.