Hepatitis A rates have dropped sharply in the U.S., and routine kids' vaccinations may be a big reason why.
Hepatitis A rates in the U.S. were 76 percent lower in 2003 than they were in 1990-1997. That's the country's lowest rate since record keeping began 40 years ago.
The drop followed routine vaccination recommendations for kids living in states with consistently high hepatitis A rates, write the CDC's Annemarie Wasley, ScD, and colleagues in The Journal of the American Medical Association.
"Since 2001, rates in adults have been higher than among children," write the researchers.
The highest rates are now among men aged 25-39.
The largest proportion of adult cases is in states with historically low hepatitis A rates, the researchers report.
Read WebMD's "Learn More about Hepatitis A"
About Hepatitis A
Hepatitis A is a liver infection spread by the hepatitis A virus. It is the most common type of viral hepatitis.
The disease usually causes temporary liver inflammation. Most people recover without any long-term liver problems.
The virus is mainly spread by oral contact with feces containing the virus. In the U.S., most people become infected through contact with a household member who has the virus (such as from changing a diaper) or a sex partner who is infected.
The virus may incubate for two to seven weeks or so before symptoms appear.
Symptoms may include extreme tiredness, fever, sore muscles, headache, pain on the right side of the stomach under the rib cage, nausea, loss of appetite, and weight loss.
Some patients may also develop jaundice -- yellowing of the skin and the white part of the eyes, sometimes with dark urine or clay-colored stools.
Jaundice is more common in older people than among children and young adults.
Read WebMD's "Hepatitis A Outbreak: Are You at Risk?"
Then and Now
In the 1980s and 1990s, there were nearly 26,000 cases of hepatitis A annually in the U.S. Children accounted for more than half of those cases.
In 1995, a "highly effective" hepatitis A vaccine became available in the U.S. for people at least 2 years old, write the researchers.
In 1999, routine vaccination against hepatitis A was recommended for children living in 11 states with consistently high rates of the disease.
In 2003, the disease dropped to its lowest official rate ever, write Wasley and colleagues.
Read WebMD's "Actions for Preventing Hepatitis"
'Dramatic' Rate Drop
The drop was "dramatic," write the researchers.
In the 11 targeted states, hepatitis A infection rates dropped 88 percent to 2.5 per 100,000 people.
In other areas, the rate fell 53 percent, to 2.7 per 100,000 people.
Read WebMD's "WebMD Childhood Immunization Planner"
Good Timing?
Hepatitis A rates tend to peak every 10-15 years, write Wasley and colleagues.
"Certainly, the observed decline is not entirely attributable to vaccination," they write.
Could more progress be made?
Eliminating hepatitis A transmission will require expanding routine vaccine recommendations to all U.S. children, write the researchers.
By Miranda Hitti, reviewed by Brunilda Nazario, MD
SOURCES: Wasley, A. The Journal of the American Medical Association, July 13, 2005; vol 294: pp 194-201. WebMD Medical Reference from Healthwise: "Hepatitis A: Topic Overview." News release, JAMA/Archives.
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