Charles John Palenik, MS, PhD, MBA
The Centers for Disease Control and Prevention (CDC) recently released a very encouraging report concerning acute hepatitis B among children in the United States ("Morbidity and Mortality Weekly Report," Vol. 53:1015-1018, 2004). Since the 1991 adoption of a comprehensive strategy to eliminate hepatitis B virus (HBV) transmission, incidence of the disease has declined steadily.
Declines have been greatest among children and adolescents born after 1991, when universal infant HBV vaccination started. In 1995, routine vaccination of 11- to 12-year-olds began. In 1999, all children under 18 years old and not previously vaccinated were included in the program.
The CDC has completed an extensive epidemiological review of acute HBV in children and adolescents in the United States from surveillance data collected from 1990 through 2002. The CDC report indicates the overall rate of acute HBV had fallen 89 percent during the period, and racial disparities have narrowed.
From 1990 through 2002, 13,829 cases of acute HBV were reported among persons less than 19 years of age. The incidence declined from 3.03 per 100,000 population in 1990 to 0.34 in 2002. The incidence among adolescents ages 15 to 19 years was consistently higher than the incidence of younger age groups. In the 15- to 19- year-old age group, the range was from 8.69 per 100,000 in 1990 to 1.13 in 2002 (an 87 percent decline). Children and adolescents in all age groups experienced steep declines (0 to 4 years, a 92 percent decrease; 5 to 9 years, a 92 percent decline, and 10 to 14 years, a 93 percent decline). The higher incidence among adolescents 15 to 19 years old probably is attributable to the fact they were born before the recommendation of universal infant vaccination in 1991.
Incidence of acute HBV B in 1990 was highest among Asian and Pacific Islanders (6.74 per 100,000 population). Blacks were next at 4.29, and whites had the least incidence at 1.39. Declines occurred in all racial groups. In the year 2002, the highest incidence per 100,000 population was only 0.55 among Asian and Pacific Islanders, followed by blacks at 0.51 and then whites at 0.16.
In 2001 and 2002, the CDC received only 19 reports of children born after 1990 with acute HBV. Eight of these cases involved children born outside the United States. Twelve of the 19 were male, and eight were less than two years old. Seven were Asian and Pacific Islanders. The race of three of the children was unknown. Studies have indicated that international adoptees have low rates of protective titers for vaccine-preventable diseases upon arrival in the United States. This includes adoptees with written evidence of age-appropriate vaccinations provided in their birth countries.
Infants born to women who are HBsAg positive should receive both the first vaccine dose and 0.5 ml of hepatitis B immune globulin (HBIG) within 12 hours of birth at separate sites. A second dose should be administered at one to two months (at least four weeks after the first). The third dose should not occur before age 24 weeks (at least 16 weeks after the first dose and at least eight weeks after the second dose). Serologic testing of these infants for HBsAg and anti-HBsAg should occur at age 9 to 15 months. Beginning the vaccination series at birth decreases the risk for perinatal HBV transmission and better ensures successful completion of the series.
Despite the decline in acute HBV among children and adolescents, a limited number of cases continues to occur. This highlights the importance of infant vaccination and the proper completion of the three-dose vaccination series. Ideally, vaccination should occur at birth, preferably before discharge from the hospital.
Still required is enhanced surveillance of verified cases, especially concerning international adoptees and other children born outside the United States. Many of these cases lack specific risk-factor information. Further monitoring of the effectiveness of the HBV vaccination program also is required. Improved reporting by local, state, and national surveillance personnel is vital to the elimination of HBV transmission in the United States.
OSAP, the Organization for Safety & Asepsis Procedures, is dentistry's prime source for evidence-based information on infection control and prevention and human safety and health. Further information concerning HBV transmission and HBV vaccination is available on the OSAP Web site at www.osap.org.
Dr. Charles John Palenik is an assistant director of Infection Control Research and Services at the Indiana University School of Dentistry. Dr. Palenik has authored numerous articles, book chapters, and monographs, and is the co-author of the popular "Infection Control and Management of Hazardous Materials for the Dental Team." He serves on the Executive Board of OSAP, dentistry's resource for infection control and safety. Questions about this article or any infection-control issue may be directed to firstname.lastname@example.org.