THURSDAY, May 31 (HealthDay News) -- As many as 2.2 million
people in the United States may be infected with chronic hepatitis
B virus, a new study suggests.
Most of those infected come from countries in Asia and Africa,
where regular vaccination for the virus has not been routine,
researchers report.
"Hepatitis B is a common infection transmitted at birth or in
early childhood. When it's transmitted at that young an age, it
tends to remain a chronic infection," said Dr. John Ward, director
of the viral hepatitis program at the U.S. Centers for Disease
Control and Prevention and co-author of an editorial accompanying
the study.
The populations who have the infection are diverse, he said.
"This illustrates the difficulty we have in developing prevention
programs that take into account cultural and language differences,"
Ward noted.
In the United States, infants started being vaccinated for the
virus in the early 1990s and the rate of vaccination is now over 90
percent, Ward explained. So, the rate of the infection among those
born in the United States has dropped significantly, he said.
It is only in the last 10 years that efforts have been under way
to vaccinate infants in other countries against hepatitis B, Ward
added.
Many people with the virus are not aware that they are infected
and run the risk of giving it to others and becoming sick
themselves, he added.
There are effective treatments available using antiviral
medicines. Often, these drugs have to be taken for an extended
time, but when successful, the damage to the liver can be reversed,
Ward said. "It's a very effective treatment," he pointed out.
If untreated, people can develop liver cancer, which is the
third-leading cause of death around the world, Ward said.
People who come to the United States from areas where hepatitis
B is common should be tested for the virus so they can receive
treatment, he suggested.
The report will be published in the July print issue of the
journal
Hepatology.
Hepatitis B affects as many as 400 million people around the
world. If left untreated, up to 25 percent of those infected are at
risk of dying from liver cancer or liver disease.
In 2006, the CDC estimated that some 800,000 to 1.4 million
people in the United States had the virus.
For this study, a research team led by Dr. Carol Brosgart, a
member of the faculty at the division of global health at the
University of California, San Francisco, and senior advisor on
science and policy to the Viral Hepatitis Action Coalition at the
CDC Foundation, looked at all the medical literature on the
prevalence of hepatitis B around the world from 1980 to 2010.
That analysis revealed that in 2009, between 1.04 million and
1.61 million people born abroad who were living in the United
States had chronic hepatitis B.
Those infected came mostly from Asia, Africa and Central
America, accounting for 58 percent, 11 percent and 7 percent of
cases, respectively, which is much higher than previously thought,
the researchers noted.
"This study highlights an important health concern for the U.S.
and the need for broader hepatitis B screening of foreign-born
individuals," Brosgart said in a statement. "Given our ability to
treat chronic hepatitis B virus and to monitor for emergence of
liver cancer when it is treatable, physicians should screen the
foreign-born, their children and close contacts."
Another expert, Dr. Marc Siegel, an associate professor of
medicine at NYU Langone Medical Center in New York City, added that
"we have an epidemic of hepatitis B around the world and we have to
be alert to it in people who move here from other countries."
In addition, its prevalence in the United States has been
underestimated, as this study confirms, he said.
It's easy to get the virus, which is usually transmitted
sexually or through contact with infected blood or among injection
drug users, he said.
The epidemic of hepatitis B has led to an epidemic of liver
cancer around the world, Siegel added.
More information
For more on hepatitis B, visit the
U.S. National Library of Medicine.