What to Know About Influenza Before Peak Flu Season Influenza cases are increasing across the U.S.

 -- Influenza activity is on the rise across the U.S., with 10 states already reporting high levels of flu activity, according to the U.S. Centers for Disease Control and Prevention.

While getting the flu doesn't usually inspire dread among the otherwise healthy, the virus can have serious consequences for the frail. Every year, millions of people will be sickened by the seasonal flu and thousands in the U.S. will die from it.

As flu season reaches its peak in the next few weeks to months, here are a few things to keep in mind about the virus.

When Does Flu Season Peak?

While the spread of influenza can be unpredictable, generally season flu season peaks sometime between December and February, though it has been reported as late as May, according to the CDC.

"Flu varies, it's fickle sometimes it starts earlier sometimes it's later," said Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical Center.

During a 34-year study period, the CDC found that in flu activity generally peaked more often in February than other months. This year, public health experts believe the worst of the flu season has yet to arrive, Schaffner said.

"It should peak sometime in February and then it [will likely] abate through March," he said.

Is It Too Late to Get a Flu Shot?

If you've been putting off getting a flu shot, Schaffner said "run don't walk" to get the shot.

"It is not too late to get the flu shot. There is an excellent match between what is in the vaccine this year and the virus" circulating through the country, Schaffner said. The most prevalent strain currently circulating in the U.S. is influenza A (H3), according to the CDC.

However, since it takes between 10 days to two weeks for antibodies to build up after the flu shot, Schaffner said it's key to get the vaccination early.

"It's not too late [but] I wouldn't linger," he said.

Are There Other Ways to Avoid Getting Sick?

In addition to getting the flu shot, Schaffner said there are common sense actions people can take to avoid the virus. Simple steps like washing your hands and avoiding other people who are sick can go a long way in protecting you from being infected with the virus.

"Avoid people who are coughing and sneezing and if you get sick, restrict your activities," Schaffner said. "You don't want to give it to others."

Can You Treat the Flu?

Taking an antiviral like TamiFlu can help people get over the infection more quickly and can be especially helpful for those with weakened immune systems.

For the very young, very old or for those with an underlying medical condition, getting on an antiviral quickly can be key in shortening the duration of flu symptoms, Schaffner said.

"For older, the very young or anyone with underlying disease, if you get sick during flu season call your provider," to get an antiviral, Schaffner said.