Feeling achy and feverish? Your misery has plenty of company.
By the end of December, the tally of flu-like illnesses in the state exceeded the peaks in the two previous seasons, when the biggest number of cases occurred in February and March.
And while it’s unclear whether the annual flu epidemic will be worse this year, or just arrived earlier, fears have been stoked by the severity of the flu in Australia during its most recent season and the fact that the vaccine may protect against the predominant strain of the flu only 30 percent of the time.
Despite the worries, doctors and public health officials say there is no evidence that people are getting sicker than usual.
Flu cases in Massachusetts started rising around Thanksgiving and increased steadily, with an especially steep climb in the last week of the year.
“This is a bad flu season but not a horrible one,” said Dr. Andrew G. Villanueva, a lung specialist and chief quality officer at the Lahey Hospital & Medical Center in Burlington.
The flu season, while clearly in full swing, doesn’t “feel different” from previous years, Villanueva said. “We’re not seeing a lot of employees calling out sick with the flu. We’re not seeing a lot of people being hospitalized because of flu,” he said.
Of course, that could change in a heartbeat.
Even this far into the epidemic, there’s no telling what will happen next, said Dr. Alfred DeMaria, medical director of the Bureau of Infectious Disease and Laboratory Sciences at the state Department of Public Health. Cases may continue their upward trajectory, or the epidemic may have already peaked.
“Every October these experts say it’s going to be a bad flu season,” DeMaria said. “They’re just talking off the top of their heads. It’s hard to predict.”
Worries about the flu’s impact this year were inflamed by reports from Australia, which had one of its worst flu seasons ever. But DeMaria said other countries’ experiences are poor predictors of what will happen in the United States.
Another source of concern is the predominant strain of flu circulating this year, H3N2, which produces more severe illness, especially in older people. Also, in Australia, the flu vaccine protected people against H3N2 only 10 percent of the time. DeMaria said that here the vaccine seems to be 30 percent effective against that strain, a little below the 40 to 60 percent effectiveness typical of most years.
Dr. Jenifer L. Jaeger, interim medical director of the Boston Public Health Commission, said Boston is experiencing similar trends as the rest of the state. “We’re not seeing anything that makes me concerned that we’re going to see an unusually severe season,” she said. “What makes me most concerned is that people are shying away from the vaccine.”
Jaeger and others emphasized that any protection is better than none, and that while the vaccine may be relatively weak against H3N2, it does protect against other circulating strains. Even if the vaccine doesn’t prevent sickness, it can reduce the severity of symptoms. And younger people should get vaccinated so they don’t spread the illness to people who are old and sick or babies too young for the vaccine, doctors say.
DeMaria said that people over 65 or with chronic illnesses are at the greatest risk of complications from the flu and should take antiviral drugs within 48 hours of feeling ill.
Dr. Benjamin Kruskal, chief of infectious diseases at Atrius Health, a large physicians’ group, said the number and severity of flu cases are within the normal range, although at the upper edge of normal.
“It may be a bit more severe, but not dramatically so,” he said. “It’s certainly possible, if it increases substantially, it will put a burden on our health care system,” Kruskal said. So far, doctors’ offices are busy but not overwhelmed, he said.
By the end of the 2017 season, influenza was widespread in every state except Maine, New Hampshire, New Jersey, and Hawaii, according to the Centers for Disease Control and Prevention.
Health officials track the epidemic with reports filed by outpatient health care providers who have agreed to serve as “sentinels.” These sentinel sites, which include doctor’s offices and community health centers, report the percentage of visits to treat “influenza-like illnesses” — cases involving a fever and cough or sore throat. Not all these illnesses are flu, but tracking them is considered a reliable indicator of the epidemic’s spread.
In Massachusetts, influenza-like illnesses had reached nearly 3 percent of doctor’s visits in the last week of December, which the CDC considers “moderate activity.” That’s worse than in all the other New England states, where influenza-like illnesses are minimal to low. But it’s better than in most of the country — 26 states have high levels of influenza-like illnesses.
Across Massachusetts, the severity of the epidemic varies. The hardest hit area of Massachusetts is the northeast corner, where influenza-like illnesses reached nearly 5 percent.
Even so, Lawrence General Hospital is not seeing much change from the previous season. There have been 51 flu cases to date, compared with 53 last year, said spokeswoman Jill McDonald Halsey.Felice J. Freyer can be reached at email@example.com. Follow her on Twitter @felicejfreyer.