Flu season has come early this year due to a strain of the virus not typically seen during this time of year, according to the Centers for Disease Control and Prevention. The CDC announced Friday there has already been an estimated 1.7 million flu illnesses, 16,000 hospitalizations, and 910 flu-related deaths this year in the United States, at a minimum.

The early activity is primarily being caused by influenza B/Victoria viruses, which is unusual this early in the season, according to the CDC. CBS News medical contributor Dr. David Agus told "CBS This Morning: Saturday" that the B/Victoria strain "classically" happens in February or March.

"Nationally, influenza B/Victoria viruses are the most commonly reported influenza viruses among children age 0-4 years (46% of reported viruses) and 5-24 years (60% of reported viruses)," reads the agency's website. 

B/Victoria viruses are generally not dangerous to older people. 

Flue season is considered to be underway when a significant percentage of doctors visits — for at least three weeks straight— are attributed to flu-like symptoms, the Associated Press reports. As of November 30, flu activity had been elevated in the United States for about four weeks, and is expected to increase as we move into winter, according to the CDC. 

The virus has largely hit the Southern United States. At the end of November the CDC recorded high flu activity in Alabama, Georgia, Louisiana, Mississippi, South Carolina, Tennessee and Texas, among five other states and Puerto Rico. 

"We don't know why the flu season happens when or where, but it's happening early, it's clear," Agus said. "It's happening in the Southern United States — New Orleans particularly hit — and 1.7-2.5 million people, that's a big number early."

The agency's forecasting shows that the flu season is just getting started. Elevated activity is expected to continue over the next few weeks, and the season will likely peak in December (40% chance), but could peak as late as February (25% chance), according to the CDC.

"We don't know whether this is going to be an early peak — say it will peak in December — or whether this is going to be drawn out like last year," Agus said. "On an average year, 125-200 people a day die of the flu. So, this is preventable most of these deaths with the vaccine."

It is not too late to get vaccinated. According to the CDC, the flu vaccine is the best way to reduce risk from the potentially dangerous complications of the flu.