One in seven east Asian immigrants in New York City carries the hepatitis B virus

Richard Pérez-Peña:

The condition puts them at far greater risk than other Americans for deadly diseases like liver cancer and cirrhosis.

Most of the people tested had no idea that they were infected, a fact that frustrates doctors who know that with proper screening and treatment, the disease can be controlled, if not cured. But three-quarters of the people in the study had no health insurance, and even those who did had trouble getting coverage for screening.

The study, led by researchers at New York University School of Medicine, found that 15 percent of east Asians in New York — as many as 100,000 people — are chronic hepatitis carriers, with the rate highest among immigrants from China. That infection rate is 35 times the rate found in the general population.

Because Hepatitis B is endemic in many Asian countries, growth in the number of Asian immigrants in New York and across the country has made the disease a broad, expensive, emerging health problem. In the 2000 census, there were 800,000 Asians in the city, with roughly half from China.

Hepatitis B, like hepatitis C, is generally contracted through the blood, and is not transmitted through casual contact with infected people. Hepatitis A, which is caused by a different virus, can be transmitted through food, but hepatitis B cannot, with very rare exceptions.

Since the development a generation ago of a vaccine that is given to nearly all children born in the United States and to many adults who are considered at risk, hepatitis B has become rare in this country. While doctors have long worried about the disease in immigrant groups who come from countries like China — which does not have a comprehensive national vaccination program — little has been done to raise awareness of the danger.

"The health care costs are enormous," said Dr. Henry J. Pollack, the lead author of the study, which is to be published late this week in the Centers for Disease Control and Prevention's journal, Morbidity and Mortality Weekly Report. "If you're giving what would be considered to be the proper care for all these people, it would be hundreds of millions of dollars."

People can carry the hepatitis B virus for decades without showing any signs of illness, until it causes life-threatening diseases like cancer or cirrhosis. "That often is the first sign of trouble," said Dr. Pollack, an associate professor at the medical school.

The New York State cancer registry shows rates of liver cancer among Asian-Americans 6 to 10 times as high as for whites, Dr. Pollack said, a difference that is mostly attributable to hepatitis B. And those figures may underestimate the disparity, because many immigrants who become sick return to their native countries.

Hepatitis B is prevalent in many poor countries, and there are an estimated 350 million cases worldwide. It is most common in China, but scientists do not understand why. In this country, hepatitis B is associated with transmission by sex and intravenous drug use. But in Asia, the disease most commonly passes from mothers who do not know they have it to their children in the womb. It may also be transmitted among children who have close physical contact.

Dr. Thomas Tsang, another principal investigator in the study, said the results confirmed that Asian-Americans face a major health problem that is not captured by national statistics. The Centers for Disease Control and Prevention has estimated that just 0.4 percent of all Americans have chronic hepatitis B, but experts say that may undercount people from Asia.

"In this past week alone, from those people we screened, I have seen 7 to 10 people who needed to be started on medication because they had abnormal liver tests," said Dr. Tsang, who is chief medical officer of the Charles B. Wang Community Health Center in New York City. Those are people, who without the screening program, would probably have gone untreated until they got so sick they ended up in the hospital.

Representative Mike Honda, Democrat of California and chairman of the Congressional Asian Pacific American Caucus, said California faced a problem similar to New York's, one that was going largely unrecognized. "To not do something, when we know we can, is criminal," he said.

Early detection and suppression of the virus can interrupt the cycle of mother-to-child transmission. An adult immune system can usually fight off a new hepatitis B infection, though a small number of cases become chronic. But, Dr. Pollack said, "If you get it when you're an infant, your chance of getting chronic hepatitis B is greater than 90 percent."

In the last decade, doctors have been able to use an array of new drugs to treat chronic infection, but they do not cure the disease. Rather, they often suppress the virus so that it causes little or no harm. The medication must be taken for life.

Previous, smaller studies, cited in the N.Y.U. report, have also found high rates of infection among foreign-born Asian Americans, some as high as 15 percent. But the authors of the N.Y.U. report say theirs is the most comprehensive look at the problem, and the first to search not only for the number of people with hepatitis, but also for significant patterns within those numbers.

The researchers found that people from Fujian province — the biggest source of Chinese immigration to the United States in recent years — had the highest rate of infection, which corresponds to findings by the Chinese government. Men between the ages of 20 to 39 were also more likely than other groups to have the virus; overall, men were twice as likely as women to be infected.

The researchers screened 1,836 Asian-born adults last year at 12 sites in heavily Asian neighborhoods in Queens, Brooklyn and Manhattan. More screenings have been conducted this year, but those results have not yet been analyzed.

Some 61 percent of the subjects, who volunteered for the screening, were born in China, and 30 percent were born in Korea. A small number were from other parts of Asia, and those groups had much lower rates of infection than the Chinese.

Over all, 24 percent of the people screened were found to carry the virus, but that included a large number of people who said they had been tested before, and may already have known that they were infected. Those people might have sought screening to obtain confirmation or treatment. Among those who had been tested previously, 40 percent were infected.

Among those who said they had never been tested, who were just over half the subjects, 15 percent, tested positive. The researchers concluded that this figure, not the higher number, reflected infection rates in the east Asian population as a whole.

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