Published Date: 2011-10-21 18:35:06
Subject: PRO/EDR> Hepatitis B - USA: (CA) liver cancer epidemic
Archive Number: 20111021.3142
HEPATITIS B - UNITED STATES OF AMERICA: (CALIFORNIA) LIVER CANCER
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Wed 19 Oct 2011
Source: Los Altos Town Crier [abridged, edited]
Hepatitis B and liver cancer epidemics hit close to home
The Bay Area is the epicenter of a liver cancer epidemic. There are
more cases of liver cancer in Santa Clara and San Francisco counties
than anywhere in the United States. Largely caused by hepatitis B
virus (HBV) infection, liver cancer is lethal.
According to the World Health Organization (WHO), it kills nearly 750
000 people each year. The 5 year survival rate after diagnosis is just
15 per cent. The good news is that most cases of liver cancer can be
prevented. There is an effective and safe vaccine for HBV that the
Centers for Disease Control and Prevention and WHO call the 1st
"anti-cancer" vaccine. HBV is also easily diagnosed with a simple
blood test. The challenge is to educate, test and vaccinate as many
people as possible, especially those at greatest risk.
HBV, which can appear in either chronic or acute form, is responsible
for 80 per cent of liver cancers. HBV is called a "silent killer"
because most people with chronic infection often have no symptoms. By
the time they realize they have the disease, it is too late for
effective treatment. Sometimes people only find out about the disease
when they are diagnosed with liver cancer. Untreated, HBV can also
lead to cirrhosis and liver failure.
HBV is transmitted much the same way as HIV/AIDS. It is only
transmitted through blood or semen, but it is 100 times more
infectious than HIV. It cannot be transmitted through casual contact.
No one is immune, but liver cancer is especially prevalent in people
from Asia and the Pacific Islands. The statistics are staggering.
Asians and Pacific Islanders make up 4.5 per cent of the US population
but account for more than 50 per cent of chronic hepatitis B cases.
Recent immigrants are at greater risk. Two-thirds of those infected
are unaware that they have HBV. Many acquired the virus at birth from
mothers who were unaware they were carriers. In Santa Clara County,
where an estimated one-third of the population is of Asian descent,
about 35 000 live with chronic HBV [infection]. A quarter of those
with chronic HBV will die from liver cancer.
[byline: Nancy Dickenson]
ProMED-mail from HealthMap alerts
[Worldwide, an estimated 2 billion people have been infected with the
hepatitis B virus (HBV), and more than 350 million have chronic
(long-term) liver infections. A vaccine against hepatitis B has been
available since 1982. Hepatitis B vaccine is 95 per cent effective in
preventing HBV infection and its chronic consequences, and is the 1st
vaccine against a major human cancer.
The likelihood that an HBV infection will become chronic depends upon
the age at which a person becomes infected, with young children who
become infected with HBV being the most likely to develop chronic
infections. About 90 per cent of infants infected during the 1st year
of life develop chronic infections; 30 per cent to 50 per cent of
children infected between one to 4 years of age develop chronic
infections. About 25 per cent of adults who become chronically
infected during childhood die from HBV-related liver cancer or
cirrhosis. About 90 per cent of healthy adults who are infected with
HBV will recover and be completely rid of the virus within 6 months.
Hepatitis B is endemic in China and other parts of Asia. Most people
in the region become infected with HBV during childhood. In these
regions, 8 per cent to 10 per cent of the adult population are
chronically infected. Liver cancer caused by HBV is among the first 3
causes of death from cancer in men, and a major cause of cancer in
women. High rates of chronic infections are also found in the Amazon
and the southern parts of eastern and central Europe. In the Middle
East and Indian sub-continent, an estimated 2 per cent to 5 per cent
of the general population is chronically infected, whereas less than 1
per cent of the population in western Europe and North American is
chronically infected. Hepatitis B virus is transmitted between people
by contact with the blood or other body fluids (semen and vaginal
fluid) of an infected person. Modes of transmission are the same for
the human immunodeficiency virus (HIV), but HBV is 50 to 100 times
more infectious. HBV is not spread by contaminated food or water, and
cannot be spread casually in the workplace.
Liver cancer is almost always fatal, and often develops in people at
an age when they are most productive and have family responsibilities.
In developing countries, most people with liver cancer die within
months of diagnosis. In higher income countries, surgery and
chemotherapy can prolong life for up to a few years in some patients.
All children and adolescents younger than 18 years old and not
previously vaccinated should receive the vaccine. People in high risk
groups should also be vaccinated, including: persons with high-risk
sexual behaviour; partners and household contacts of HBV infected
persons; injecting drug users; persons who frequently require blood or
blood products; recipients of solid organ transplantation; those at
occupational risk of HBV infection, including health care workers; and
international travellers to countries with high rates of HBV. (For
further information, see: WHO Factsheet at
recent review of the genetic basis of susceptibility to chronic
hepatitis B can be found at: Semin Liver Dis. 2011 May;31(2):115-27.
Epub 2011 May 2. Understanding the host genetics of chronic hepatitis
B and C. By M Thursz, L Yee, and S Khakoo.)
It would seem that greater efforts should be made to extend
vaccination coverage in Santa Clara and San Francisco counties. A map
showing the locations of the counties of Santa Clara and San Francisco
can be found at http://www.counties.org/default.asp?id=6 - Mod.CP]