For the first time, researchers have used a vaccine to completely prevent the spread of hepatitis A, a sometimes deadly liver infection.
Hepatitis experts said the vaccine was a major advance against the disease, which afflicts tens of thousands of Americans and can kill in its most virulent form.
The vaccine was tested in 1,037 children in the Kiryas Joel community in Monroe, N.Y. This community of Hasidic Jews has been plagued by rampant hepatitis A infections. Half the children were given the vaccine and half were given a dummy injection. None of those who were vaccinated got hepatitis A. Many of those who were not vaccinated did.
The manufacturer of the vaccine, Merck Sharp & Dohme Research Laboratories in West Point, Pa., hopes to apply to the Food and Drug Administration in the first six months of 1993 for a license to sell it, said Dr. R. Gordon Douglas, president of the company's vaccine division. He said Merck hoped to market the drug in 1994.
One remaining question, the experts said, is whether everyone should receive it or whether it should be given mainly to people in high-risk groups. These groups include travelers to areas like Central and South America, Africa, some Mediterranean countries and Eastern Europe, where the disease is endemic. Other people at risk include military recruits, prisoners, health care workers, food handlers, people who eat raw shellfish, children in day-care centers, and adults who work in these centers.
Dr. Jules Dienstag, a liver specialist and virologist at the Massachusetts General Hospital in Boston, said the vaccine results were "a great breakthrough."
Dr. Jay H. Hoofnagle, the director of the division of digestive disease and nutrition at the National Institute of Diabetes, Digestive and Kidney Diseases, agreed. "This is a major advance," he said.
The vaccine study, by Dr. Alan Werzberger at the Kiryas Joel Institute of Medicine and his colleagues, is being published today in the New England Journal of Medicine.
In an editorial accompanying Dr. Werzberger's paper, Dr. William H. Bancroft of the Army Medical Research and Development Command wrote that "it has taken decades of research and contributions by manyinvestigators to reach this point."
Dr. Miriam Alter, chief of the epidemiology section of the hepatitis branch at the Centers for Disease Control, said the number of hepatitis A cases reported varies widely from year to year. In 1991, about 29,000 cases were reported in the United States. She said that more cases go unreported than are reported, partly because children who are infected may have no symptoms and so their disease goes unrecognized.
Although most people recover from hepatitis A infections, the disease can be severe, said Dr. Robert Perrillo, a hepatitis expert at Washington University in St. Louis. The virus "can cause a lot of misery and some deaths," he said.
Most people infected with hepatitis A feel ill for two to four weeks with nausea, malaise and jaundice. Then they recover completely. But Dr. Perrillo said about 1 percent of hepatitis A patients develop a raging infection that can lead to liver failure in days to weeks. Eighty percent of these people die unless they receive a liver transplant.
Hepatitis A is spread through fecal-oral contamination. A child in a day-care center may be infected. An adult changes the child's diaper and gets the virus on her hands. She then infects other children. They go home and spread the disease to their families. Or a chef in a restaurant may be infected, neglect to wash his hands before handling food, and generate an outbreak of the disease among people who eat food he prepares.
One of the problems researchers faced in testing a hepatitis A vaccine is that it is hard to predict where outbreaks will occur. But Dr. Werzberger was able to get around that problem by studying the Kiryas Joel community, which is highly unusual because it is plagued by yearly epidemics of hepatitis A.
For the study, the investigators recruited 1,037 children aged 2 to 16 who had not been exposed to the hepatitis A virus, as determined by a lack of antibodies to the virus in their blood. The 519 children who received a single dose of the vaccine had no hepatitis A infections. Twenty-five of the 518 who received a dummy injection became infected.
Experts said thatthey expected the vaccine to be licensed shortly.