Health officials predict we could be in the midst of one of the worst flu seasons in years. More folks are getting sick, and the bug going around is a more severe type of flu.

It's still early in the flu season, but cases of the illness have shot up. Patients have been filling up doctors' offices, urgent care centers, and emergency rooms across the state.

In Pennsylvania, more than 3,000 people are sick with the flu. In the Lehigh Valley, doctors are treating upwards of 700 people. Reading Health System said it currently has 80 patients in isolation with flu-like symptoms and as many as 200 others are flooding the emergency room each day.

Doctors said patients are sicker than usual, and they're seeing more cases than in past flu seasons.

"We're in the midst of a fairly sharp increase in the number of cases," said Dr. Luther Rhodes, chief of infectious diseases for the Lehigh Valley Health Network.

Through Dec. 22, the CDC said flu was classified as widespread in 31 states, including Pennsylvania. This season, the predominant strain is H3N2. It is covered by the vaccine, but it's notorious for causing serious illnesses.

"H3N2 is the more severe type of flu, so we actually anticipated what we're seeing now, that is, increased numbers of seriously ill people," explained Rhodes.

As of Dec. 29, more than 200 Pennsylvanians were hospitalized with the flu.

Rhodes said the symptoms are typical: "Abrupt onset of high fever, shaking, chills, headache and cough."

If you haven't been vaccinated, health experts said now is the perfect time. The flu shot protects you and the people around you and is recommended for anyone six months and older.

When children get sick, they're contagious for eight to 10 days, while an adult usually can only pass it on for five days.

"If you're sick, stay home," urged Rhodes. "On average, people need to be out of work three to five days."

The vaccine only takes 60 percent of the time in people over the age of 60, but the shot still helps those folks; usually they'll get a less severe form of the flu.