THURSDAY, March 15, 2007 (HealthDay News) -- U.S. rates of infection with hepatitis A, B and C viruses have fallen to historic lows, reducing the threat of liver disease, according to a new federal report.
Infection with these three most common forms of acute viral hepatitis have dropped dramatically between 1995 and 2005, the U.S. Centers for Disease Control and Prevention announced Thursday. Moreover, the rates of hepatitis A and B are now at their lowest levels since the federal government began collecting data more than 40 years ago, according to the CDC report, Surveillance for Acute Viral Hepatitis -- United States, 2005.
The rates of all three types of hepatitis have been dropping dramatically since the mid 1990s, noted the report's lead author, Annemarie Wasley, a CDC epidemiologist in the Division of Viral Hepatitis.
"Since 1995, there has been an 88 percent decline in hepatitis A and a 79 percent decline in hepatitis B. For hepatitis C, since the early 1990s, it's been a 90 percent decline," she said.
The statistics were published in this week's issue of the CDC journal Morbidity and Mortality Weekly Report.
Hepatitis A can affect anyone and can be contracted through contaminated water, food or person-to-person contact. Hepatitis B can be contracted through sexual contact and is a serious disease that attacks the liver, resulting in lifelong infection, cirrhosis of the liver, liver cancer, liver failure, and death. Hepatitis C can also lead to serious liver disease. It is spread by contact with the blood of an infected person.
"A lot of the decline in hepatitis A and B is due to the national vaccination strategy since the 1990s," Wasley said.
The greatest decline in hepatitis A was seen among children in those 17 states where vaccination of children has been recommended since 1999. For hepatitis B, the greatest decline was among children and teens age 15 and younger, likely due to a high vaccination rate in this age group, according to the report.
"We think a lot of the decline in cases of hepatitis C is the result of changing behaviors among intravenous drug users. They are one of the most important risk groups for hepatitis C," Wasley said. "In addition, we have better screening of blood for hepatitis C."
Education programs aimed at people at risk for hepatitis C are also credited with reducing the number of new cases, by promoting behaviors to reduce person-to-person transmission of the virus, Wasley said.
There is currently no vaccine for hepatitis C.
Wasley expects rates of hepatitis A and B to drop even further. "There may be upsurges over the next few years, but the general trend, we expect and hope, will continue to decline," she said.
"For hepatitis A, the CDC recommends that all children 12 months to 23 months be vaccinated," Wasley said. The vaccine is also recommended for people at risk for infection, including international travelers, men who have sex with men, injection and non-injection drug users, and children living in communities with high rates of the disease.
For hepatitis B, the CDC recommends three doses of vaccine beginning at birth. In addition, hepatitis B infection rates also dropped among adults but remain highest among those 25 to 44 and among people with risk factors, such as high-risk sexual activity and injection drug use.
As more children are vaccinated, the hope is the hepatitis B can eventually be eliminated, Wasley said.
"It's a little harder to see what's going to happen with hepatitis C," Wasley said. "Because without a vaccine we rely on education," she said. "We hope rates will continue to decline. We are making tremendous inroads in reducing the occurrence of all of these diseases, but there are challenges remaining."
More than 4.5 million Americans are currently infected with chronic hepatitis B and/or hepatitis C and at serious risk for liver cirrhosis and cancer.
One expert said that although much progress has been made there is still a lot to do, especially for people with hepatitis C.
"It is estimated that 50 percent of people with hepatitis C have not been identified," said Thelma King Thiel, chairman and CEO of Hepatitis Foundation International. "We are trying to educate people who have used intravenous drugs to get tested. It's hard to get people to assess their own risk behaviors."
Thiel believes that, since there is no vaccine for hepatitis C, it will require a concerted educational effort to reach those at risk.
"The progress has been great in hepatitis A and good in hepatitis B, but there needs to be more education to be sure that all children are vaccinated and reach people who have not been vaccinated," Thiel said. "It's even harder to reach people to educate them about hepatitis C," she added.
More information
For more information on hepatitis, visit the U.S. Centers for Disease Control and Prevention.
