BOSTON — Health officials say this flu season is shaping up to be one of the worst in decades as the number of confirmed cases continues to climb.
At least 2,900 confirmed cases of influenza have been reported in Massachusetts so far this winter, compared with about 700 during the same period in 2018-19, according to the state Department of Public Health, which publishes weekly updates.
That includes a spike of about 1,300 reported cases in the most recently reported period — Dec. 14-28, which prompted state health officials to raise the "influenza severity" level from low to moderate.
"We're on track for a serious flu season," said Dr. Larry Madoff, director of the department's Division of Epidemiology and Immunization. "We are seeing a high level of activity throughout the state and well above what we saw last year at this time, and last year was a bad season."
Madoff urges people to get vaccinated, take precautions and "stay home when sick to limit the spread of disease."
Nationwide, the flu is widespread in 45 states — including Massachusetts and New Hampshire — with an estimated 6.4 million confirmed cases and 55,000 hospitalizations reported from Sept. 29 to Dec. 28, according to the U.S. Centers for Disease Control and Prevention.
The federal agency, which also publishes weekly updates, said so far this season at least 2,900 deaths — including 27 children — have been attributed to the flu and pneumonia.
That’s the highest number of pediatric flu-related deaths at this point in the season since the CDC started keeping records 17 years ago, the agency said.
No child fatalities have been reported in Massachusetts, which lost four children to flu complications in the previous season. New Hampshire also hasn't reported any child fatalities.
"Unfortunately, it's a real tragedy when a child dies of the flu, and I'm grateful that we haven't had any in Massachusetts yet," Madoff said. "But it's a bad season, so it wouldn't surprise me if we do see pediatric deaths locally."
Each year, influenza kills 12,000 to 49,000 people and can send as many as 700,000 people to the hospital, according to the CDC.
It affects so many people that adult cases and deaths can only be estimated.
Last flu season began as a mild one but turned out to be the longest in a decade. It ended with about 49,000 flu-related deaths and 590,000 hospitalizations, according to the CDC.
Two years ago, the flu, and complications from it, killed an estimated 61,000 people nationally — the highest death toll in decades, health officials said.
Influenza is a contagious respiratory illness. It can cause a relatively mild illness in many people but more severe illnesses in others. Young children and the elderly are most at risk.
Symptoms generally include a fever, sore throat, body aches and headache.
Health officials warn people to cover their mouths when coughing, avoid people who are ill, and stay home when feeling symptoms.
Health officials also recommend annual flu vaccines for anyone 6 months or older — especially pregnant women, the elderly and children.
The vaccine may not prevent the flu, but the CDC says it can reduce the severity of symptoms and the length of illness.
Despite education campaigns, too many people don't receive the flu shot, putting them at risk, health officials say. Nationwide, only about 45 percent of adults get the shot each year.
Christian M. Wade covers the Massachusetts Statehouse for North of Boston Media Group’s newspapers and websites.