New York -- According to a new study by New York University School of Medicine researchers, an estimated 15% of Asians living in New York City are severely infected with hepatitis B virus. Chronic hepatitis B infection is associated with a condition where the liver gets inflamed and can ultimately lead to cirrhosis and liver cancer.
The new study appears in the May 12 issue of Morbidity and Mortality Weekly, published by the Centers for Disease Control and Prevention (CDC).
A total of 1,836 people were screened at 12 health care centers and community sites in New York City as part of the NYC Asian American Hepatitis B Program, which provides free screening, vaccination and treatment. It is funded by the New York City Council and the New York State and City Departments of Health. Nearly all of the participants were born in Asia; mainly in China and Korea. The was drawn from an analysis of 925 people who had never been previously tested for hepatitis B.
A person's country of birth, gender and age influenced the prevalence of chronic infection, according to the study. The infection rate was highest--greater than 30 percent--in men between 20 and 39 who were born in mainland China.
"These rates are extraordinarily high and underscore the need for more intensive screening in this population," says Henry Pollack, M.D., Associate Professor of Pediatrics at NYU School of Medicine, and the study's lead author. "There needs to be much more public awareness of this problem and physicians caring for this population need to be more attentive to screening for hepatitis B," he says.
Hepatitis B is transmitted through unprotected sex, sharing of needles, contact with infected blood, or from mother to child at birth, but not through casual contact such as hugging or coughing. Symptoms start when the immune system starts attacking the cells in the liver that are infected with the virus. Liver damage can take decades to progress. An estimated 400 million people worldwide are chronically infected with hepatitis B.
The viral infection is widespread across Asia and if left unchecked, it causes liver cancer, which is a leading cause of death in many Asian countries. New York City has the largest Asian population in the United States--about 800,000 people, according to the 2000 U.S.
Census. "Hepatitis B is probably responsible for 80 percent of hepatocellular cancers worldwide," says Dr. Pollack. When infection occurs in young children, an estimated 15 percent to 40 percent will develop chronic liver disease, including cirrhosis and liver cancer. "In newborns there is a 90 percent chance of developing chronic hepatitis B," he says.
Over the last 15 years, the transmission of hepatitis B from mothers to newborns in the United States has been drastically reduced with the help of neonatal screening and vaccination. In China, prophylaxis efforts have only just begun, due to a lack of resources across the country. China has 150 million people who are chronically infected with hepatitis B, says Dr. Pollack. In the 1990s there was a large influx of immigrants from China to the United States. So now the U.S. faces a somewhat under-recognized public health challenge, he says, because the disease has been considered controlled.
About one in five persons screened in the new study who were born in China were infected with chronic hepatitis B. In general, the infection rate among those tested closely mirrored rates reported in the study participants' native countries and regions, says Dr. Pollack. Once diagnosed, proper evaluation and care and, in many cases, specific antiviral treatment, is the key to avoiding long-term complications of the disease. Hepatitis B infection can be effectively prevented by vaccination. All persons susceptible to infection in the new study were vaccinated against hepatitis B. Partners and other household members were also tested and vaccinated if susceptible.
The long-term goal of The Asian American Hepatitis B Program is to establish a national model for hepatitis B prevention in Asian American communities, according to Mariano J. Rey, M.D., Director of the Centers for Health Disparities Research at NYU School of Medicine and the program's administrative principal investigator.