NEW YORK — The U.S. flu season keeps getting worse.

Health officials said Friday that 7.5% of outpatient medical visits last week were due to flu-like illnesses. That’s as high as the peak of the 2017-18 flu season and higher than any season since.

The annual winter flu season usually doesn’t get going until December or January, but this one began early and has been complicated by the simultaneous spread of other viruses.

The measure of traffic in doctor’s offices is based on reports of symptoms like coughs and sore throats, not on lab-confirmed diagnoses. So it may include other respiratory illnesses.

That makes it hard to compare to flu seasons from before the COVID-19 pandemic. Other years also didn’t have this year’s unusually strong wave of RSV, or respiratory syncytial virus, a common cause of cold-like symptoms that can be serious for infants and the elderly.

Meanwhile, 44 states reported high or very high flu activity last week, the Centers for Disease Control and Prevention said Friday.

That may not bode well for the near future. It’s likely there was more spread of respiratory viruses during Thanksgiving gatherings and at crowded airports, experts say.

The dominant flu strain so far is the kind typically associated with higher rates of hospitalizations and deaths, particularly in people 65 and older.

The CDC estimates there have been at least 78,000 hospitalizations and 4,500 deaths from flu so far this season. The deaths include at least 14 children.

Flu shots are recommended for nearly all Americans who are at least 6 months old or older.