activity is high and continues to increase across the country, according to the U.S. Centers for Disease Control and Prevention (CDC).

A total of 47 U.S. jurisdictions experienced "high" or "very high" flu activity in the week ending Nov. 26, up from 36 jurisdictions a week before, CDC data showed. About 20,000 hospitalizations from flu were reported across the country in the week.

There have been at least 8.7 million illnesses, 78,000 hospitalizations, and 4,500 deaths from flu so far this season in the United States, according to the CDC.

Among them, a total of 14 pediatric flu deaths were reported.

CDC data showed the percentage of outpatient visits for respiratory illness this season has significantly outpaced that of any other season since at least 2017-2018.

Health officials warned that the United States should expect a worse than normal flu season, as this winter will be the first in which many resume normal activities.

They urged everyone ages 6 months and older to get flu vaccine annually to protect against flu.

"Vaccination helps prevent infection and can also prevent serious outcomes in people who get vaccinated but still get sick with flu," said the CDC.

Health experts have warned of a "tripledemic" facing the country as COVID-19 lingers, and influenza and RSV cases surge.

The daily average of COVID-19 hospitalizations rose again in the United States amid winter surge, according to the latest CDC data.

The country averaged about 4,200 daily COVID-19 hospitalizations in the week ending Nov. 29, a 17.6 percent increase from a week before.

COVID hospitalizations last week reached their highest level in three months, with more than 35,000 patients being treated, according to Washington Post data tracking.

Experts said that holiday gatherings are a prime time for the coronavirus to spread as millions of Americans travel and get together.

"It could be in a week or two we are seeing many more COVID patients than we are seeing RSV or flu, but the real concern is we will see a large influx of all of them really stressing out the hospitals' capacity to care for these very sick patients," said Nancy Foster of the American Hospital Association.

RSV is a common and typically mild virus, but millions of children are encountering it. The surge in child cases led to pediatric hospitals becoming overrun with patients.