More cases of hepatitis A have already been reported in Massachusetts this year than during all of last year, including at least four restaurant workers, but the state's top public health official said yesterday that the increase was not a cause of serious concern.
Through May, 285 cases of the viral illness had been reported, 68 more than in all of 2003, according to the Massachusetts Department of Public Health.
"We don't know why we've had the spike," said Public Health Commissioner Christine Ferguson, adding that the disease tends to occur in cycles. Similar increases in reported cases were seen in Massachusetts in 2001 and 1997.
Nationwide, hepatitis A follows a similar cyclical pattern, with increases every 10 to 15 years. The last peak occurred in 1995, according to the website of the Centers for Disease Control and Prevention.
The latest case in a Boston-area restaurant worker was reported this week at an Arlington branch of Not Your Average Joe's. State and Arlington health officials urged customers who ate bread or had drinks at dinner last Wednesday to get an immune globulin shot, which may prevent or reduce the symptoms of hepatitis A.
The Arlington Board of Health will administer shots at a clinic at the Symmes Hospital site tomorrow from 4 to 7 p.m.
The restaurant issued a statement yesterday, saying it is working with the board of health and "will continue to operate under the highest standards."
No hepatitis cases have been reported among customers of any of the restaurants with ill workers.
"Unlike the flu, hepatitis A is not something that is going to seriously hurt you," Ferguson said in an interview, noting that it is very rarely fatal.
Hepatitis A's flulike symptoms usually subside within two weeks, leaving people immune. Many of them are not aware that they had the disease.
Although the increase in cases has not been linked to any specific groups, at-risk populations such as the homeless, drug users, and prisoners who account for 30 percent of all reported cases -- have been targeted by the state Department of Public Health's vaccination program since March.
Ferguson said the best protection against the disease for the general population is simple: Wash your hands.
"The most effective thing you can do to protect yourself from hepatitis A, and the flu and SARS included, is wash your hands: 20 seconds under the faucet, with soap and hot water," she said.