(NBC NEWS) -- Flu season generally doesn't get rolling for another month or so but experts say the one predictable thing about the flu is its tendency to be unpredictable.
That's why doctors say now is the time to get the flu vaccine.
That's because it can take up to two weeks to be fully immunized and last year, flu season came early, and with a vengeance.
"Influenza activity started earlier than usual, was intense, and remained elevated for 15 consecutive weeks," said Dr. Howard Koh of the U.S. Department of Health and Human Services.
Last year 164 children died from influenza despite a record number of kids receiving the flu vaccine.
Just 51% of pregnant women, though, got the shot.
Pregnant women are especially vulnerable to flu complications, yet only 51% got the vaccine last year.
"Pregnant women -- more than half vaccinated -- but let's get the other half," said Dr. Anne Schuchat of the Centers for Disease Control and Prevention.
Infectious disease experts are also encouraging health care workers to get vaccinated not only to help protect themselves, but also their patients.
Last year, 90% of the medical staff at New York Presbyterian Hospital was immunized.
If they don't get the vaccine, health workers there are required to wear a mask at all times.
"I'm hoping that rather than avoiding the (pauses) stigma of wearing a mask, that people will do the right thing because what we're really trying to do is protect our patients," said Dr. Richard Leibowitz of New York Presbyterian Hospital.
There are more flu vaccine options than ever this year.
Some protect against three flu strains, some protect against four.
Others are formulated especially for people who have egg allergies.
Companies expect to make more than 135 million doses this year.
You can log onto vaccines.gov to find flu shot providers closest to you.