Mayor Thomas M. Menino declared a public health emergency Wednesday morning because of the expanding flu outbreak. Health care centers across the city will be offering free vaccines to anyone who hasn’t yet been immunized. The city has 700 confirmed cases of flu so and four flu-related deaths. Last year Boston had only 70 confirmed cases.

Massachusetts has had 18 flu-related deaths so far this season, according to the state Department of Public Health.

“We’re off to an early start nationally and in Massachusetts,” Kevin Cranston, director of the DPH Bureau of Infectious Disease, told reporters today before a meeting of the state Public Health Council. While the last two flu seasons have been mild, this one is on pace to be a “moderately severe” season, he said. “This is probably on its was to be more severe than average but still not unprecedented in severity.”

The good news is that the strains of flu virus in circulation this year were anticipated, and 91 percent of the viruses found in testing this year are well-matched to the vaccine, Cranston said in urging people to get vaccinated.

There are ample supplies of the shot, he said, adding, “It’s never too late to vaccinate.”

Confronting an earlier and a harsher than usual flu season, hospitals and other health care facilities are limiting visitors who may potentially infect sick or elderly patients with the virus -- precautions not seen since the 2009 H1N1 “swine flu” pandemic.

UMass Memorial Medical Center this week decided to ban visits from children under 16, since kids frequently contract the virus in school, and only allow patients to have two visitors at a time. “This is something we do during any type of outbreak,” said Dr. Robert Klugman, the hospital’s chief quality officer. “We had these restrictions when H1N1 was circulating.”

Read the full Boston Globe Article