(Click on image to enalrge). With a growing number of swine flu cases reported at schools, emergency rooms and hospitals in a majority of the state’s 21 counties, New Jersey today became the 47th state where the virus is “widespread,” health officials said. Until this week, the spread of this novel strain of flu was “regional,” meaning physicians had reported cases of influenza-like illness in two to 10 counties and recent laboratory results had confirmed cases of swine flu, also known as H1N1 flu.

Through its weekly assessment of school absenteeism reports, visits to hospital emergency rooms and physicians, more cases of the flu have been found and in more counties, particularly in south Jersey, state epidemiologist Tina Tan said.

“We don’t know if we have it in every county, but in most counties we are seeing elevated levels” of H1N1, Tan said. The counties don’t matter — they could change from week to week. It’s a very fluid, dynamic picture.’’

The spread of the illness does not mean the virus has become more virulent, state Health and Senior Services Commissioner Heather Howard said.

“While any type of flu is cause for concern, it is not cause for alarm. I urge all residents to stay informed and take simple preventive measures to stay healthy,’’ she said, stressing frequent hand-washing and remaining home from work and school when people are sick.

The demand for vaccine continues to mount, though supplies continue to trickle in. Only 567,000 doses out of the 1.3 million requested have arrived so far, state officials said.

“Our phones are ringing off the hook,’’ said George Van Orden, health officer for several Morris County towns. “Many calls are from outside the area, even out of state, from people who are panicking and want the vaccine right away.’’

Based on federal guidelines, the injectable vaccine should first go to pregnant women, health care workers with direct patient contact, caregivers for infants, children and young adults up to age 24, and those 25 to 64 with underlying medical conditions, including diabetes, asthma and heart, lung or neurologic diseases.

Those facts are being hammered home on health agency websites, fliers, recorded phone messages and advertisements. Health officials say they are relying on people to be honest.

“We’re counting on the best side of human nature, for those not at high risk to step aside. So far, that’s what they’ve done,’’ said Garry Annibal, health administrator in Harding Township, where 133 swine flu shots and 45 nasal spray doses were administered last week.

Essex County distributed its first 2,000 doses to the county’s 21 towns — not including Newark, which has its own program — and targeted police, fire and emergency responders, said Essex County Executive Joseph DiVincenzo. They will target those at-risk when more vaccine arrives, he said.

Since the outbreak began in the spring, 19 people in New Jersey have died, including 3 children.

Howard also announced a “find a flu shot locator” function on the state website at www.nj.gov/health. Additional information on H1N1 flu is available at the federal website, www.flu.gov.