The number of swine flu cases in Massachusetts is much higher than the 1,957 reported last week by the state Department of Public Health, according to state and local health officials. That’s because most people who have become ill since the virus arrived in the state last April were never tested for the H1N1 virus.

The number of swine flu cases in Massachusetts is much higher than the 1,957 reported last week by the state Department of Public Health, according to state and local health officials.


That’s because most people who have become ill since the virus arrived in the state last April were never tested for the H1N1 virus.


“Everyone acknowledges that the confirmed cases greatly underestimate the amount of flu that was really out there,” said Dr. Richard Herman, chief of the emergency department at Good Samaritan Medical Center in Brockton.


“It was the tip of the iceberg,” he said.


There were 30 deaths in the state from H1N1 between April 26, when the virus was first detected, and Jan. 14, the day of the last report from the state Department of Public Health.


There could have been deaths from swine flu that went undetected, said Jennifer Manley, a spokeswoman for the state Department of Public Health. If a patient died in a hospital without being tested for the virus, and family members did not seek an autopsy, there would be no way to tell whether the death was caused by swine flu, Manley said.


But local hospital officials said they were confident all severely ill patients at their hospitals were properly diagnosed and it’s unlikely anyone could have died from a case of swine flu without being detected.


Signature Healthcare Brockton Hospital, Good Samaritan Medical Center, Morton Hospital and Medical Center in Taunton and South Shore Hospital in Weymouth did not report any deaths from swine flu during 2009.


Patients hospitalized with severe symptoms were given a test — more reliable than the quick test administered in doctors’ offices — and treated immediately with anti-viral medication, the hospitals said.


“It’s unlikely that anyone slipped through without being labeled as such,” said Dr. Marc Greenwald, chief of medicine at Signature Healthcare-Brockton Hospital. “It’s highly unlikely, unless they never sought medical care.”


At Good Samaritan Medical Center, Herman said patients with mild flu-like symptoms were not tested for swine flu because the rapid test was unreliable. Instead, they were presumed to have the flu and told to rest at home until they felt better. Those with mild symptoms but with underlying conditions — diabetes, pregnancy, lung problems, and the very old and very young — were treated with anti-viral medication.


“People with severe symptoms, and definitely anyone requiring admission at the hospital,” were tested with a more reliable test that took several days to process at the state laboratory, Herman said.


“If you were in the hospital with a fever and a respiratory illness, you would have been tested for H1N1, and even before testing had come back, you would have been treated with anti-viral medication,” said Herman. “Anyone who got admitted with pneumonia would have gotten tested.”


Brockton Hospital tested all patients who were admitted with severe influenza-like symptoms, said Greenwald.


“We had some patients, including a young child, who went up to Boston and were critically ill for a few days, but recovered,” said Greenwald.


Dr. Kenneth Lawson, chief of emergency medicine at Brockton Hospital, said the “vast majority” of cases were mild and patients recovered at home.


“Very, very few needed hospitalization,” said Lawson.


The state Department of Public Health says on its Web site that the number of confirmed cases of swine flu “does not reflect the overall incidence of H1N1 flu. The majority of cases are not tested.”


Most people affected by the swine flu virus — 61 percent — were school-age children, ages 18 and younger, the state said. Twenty percent of the confirmed cases required hospitalization. Of the 30 people who died, 26 had underlying health conditions.


The state stopped reporting the counties in which swine flu victims lived once the illness became widespread, said Manley of the DPH.


Vicki-Ann Downing can be reached at vdowning@enterprisenews.com