Disease Risk – Hepatitis B

 

Risk to a child from Hepatitis B if not vaccinated until after the age of 5:

Incidence Rates:  Universal infant vaccination for Hepatitis B began in the United States in 1991.

In the United States, the most important routes of transmis­sion are sexual contact and unsanitary needles during injection-drug use. Fecal-oral transmission does not appear to occur. Perinatal transmission from mother to infant at birth is very efficient. Beyond perinatal transmission, only 5% of newly acquired Hepatitis B infection are known to be caused by a factor other than high-risk sexual activity or injection-drug use (i.e., occupa­tional, household, travel, and healthcare-related). [3]

Nationwide surveillance data showed that in the pre-vaccine era from 1983 to 1987, 161 children 1 to 4 years of age were reported with acute hepatitis B [4].  During 1990–2007, incidence of acute hepatitis B in the United States among persons aged <15 years declined from 1.2 cases per 100,000 population in 1990 to 0.02 cases per 100,000 population in 2007.[5]

As many as 90% of infants who acquire HBV infection from their mothers at birth become chroni­cally infected. Of children who become infected with HBV between 1 year and 5 years of age, 30% to 50% become chronically infected.[3]

Case Fatality Rate: Approximately 25% of persons with chronic HBV infection die prematurely from cirrhosis or liver cancer.[3]  While most acute HBV infections in adults result in complete recovery, fulminant hepatitis occurs in about 1% to 2% of acutely infected persons (case-fatality rate 63% to 93%). [3]

Rate of Long Term Sequelae or Injury: Chronic active hepatitis develops in more than 25% of carriers (a.k.a. chronic HBV infection) and often results in cirrhosis.

Incremental Risk in Population with Low Rates of Vaccination (if a child does not vaccinate by age 5): The incremental cumulative risk of permanent-injury to a child not vaccinated by age five was calculated to be 0.3 per 10,000 or 1 in 33,000.  The cumulative risk of death is the first five years of life was calculated to be 0.0035 per 10,000 or 1 in 2,849,000.  The cumulative risk of premature death later in life from Hepatitis B liver damage was calculated to be 0.075 per 10,000 or 1 in 133,000.  Incorporating both risks, the cumulative risk of either acute death in first five years or premature death later in life was calculated to be 0.0785 per 10,000 or 1 in 127,000.

Incremental Risk in Highly Vaccinated Population (if a child does not vaccinate by age 5): The incremental cumulative risk of permanent-injury to a child not vaccinated by age five was calculated to be 0.00125 per 10,000 or 1 in 8,000,000.  The cumulative risk of death is the first five years of life was calculated to be 0.0000585 per 10,000 or 1 in 171,000,000.  The cumulative risk of premature death later in life from Hepatitis B liver damage was calculated to be 0.0125 per 10,000 or 1 in 8,000,000.  Incorporating both risks, the cumulative risk of either acute death in first five years or premature death later in life was calculated to be 0.00131 per 10,000 or 1 in 7,642,000.

 

References:

[1] Centers for Disease Control and Prevention.  Notifiable Diseases/Deaths in Selected Cities Weekly Information.  MMWR2009; 56(53): 1-94.

[2] United States Census Bureau.  The 2010 Statistical Abstract; Table 78: Live Births, Deaths, Marriages and Divorces: 1960 to 2007.

[3] Centers for Disease Control and Prevention: Epidemiology and Prevention of Vaccine-Preventable Disease. Atkinson W, Wolfe S, Hamborsky J, McIntyre L. eds. 11th edition. Washington D.C.: Public Health Foundation, 2009.

[4] Centers for Disease Control and Prevention. Shapiro CN, McCaig LF, Gensheimer KF, Levy ME, Stoddard JJ, Kane MA, Hadler SC. Hepatitis B virus transmission between children in day care. Pediatr Infec Dis J. 1989 Dec; 8(12):870-5.

[5] Centers for Disease Control and Prevention. Surveillance for Acute Viral Hepatitis – United States, 2007. MMWR. May 22, 2009 / 58(S S03);1-27.  http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5803a1.htm