Going into the Thanksgiving holiday, the CDC reported 35 states experienced high or very high numbers of respiratory illnesses.
Now there are signs those family gatherings are helping to spread the sickness around.
Susan Post says her family was eager to get together, but now they're paying a price.
"We were all fine Thanksgiving Day, and then the next day, my sister called and told us that my niece was really sick, and then my sister got sick," Post said.
Medical experts had already warned of a "tripledemic" — high numbers of cases of COVID-19, the flu and RSV happening at once.
The holiday travel and large gatherings are expected to make things worse.
So far this season, the CDC estimates there have been at least 6.2 million illnesses, 53,000 hospitalizations and nearly 3,000 deaths from the flu.
In Wisconsin, the latest rate of flu cases doubled from seven to 14%.
"We're going to be at high activity in about a week, so we're anticipating things are going to get worse before they get better," said Thomas Haupt, an epidemiologist at the Wisconsin Department of Health.
A higher demand for medicine earlier in the season is creating shortages for drugs like Tamiflu or amoxicillin.
Stocks of over-the-counter remedies are also low, with it expected to get somewhat worse after the holidays.
"We can't keep them full; plus our warehouse is out of stock, and that holds us back a lot from filling the shelves," an employee at Point Loma Shelter Island Drug in San Diego said.
"I think after Thanksgiving a lot of people are calling asking about if we have over-the-counter medication or the doctor sent them prescription medication for the flu," pharmacist Dr. Hala Jolagh said.
Dr. Anthony Fauci, chief medical adviser to the president, continues to urge people to get vaccinations and boosters for COVID-19 and flu shots.
He also advises wearing masks in some situations.
"We're not talking about mandating anything; we're talking about good common sense in making a decision to put a mask on when you're in an indoor congregate setting," Dr. Fauci said.
Experts say preventive measures are key to keeping the number of illnesses down.
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