COLUMBIA, Mo. -

Those who've already battled the swine flu may not have to worry about getting it again this year.

According to the Centers for Disease Control, H1N1 is the primary strain doctors have seen this season.

This year's flu is different than most because it's affecting middle-aged, otherwise healthy people, instead of the very old or very young people that are usually hit hardest.  In fact, the CDC reports that 61 percent of flu-related hospitalizations have been in people ages 15-64.

Dr. William Roland, an infectious diseases expert at the VA Hospital, said that's because many older people have already been exposed to swine flu and are now resistant.

But that resistance hasn't worked in all cases. 

Bill Morrissey, a pharmacist at Kilgore's Pharmacy, said he's seen more people with the flu this year even after getting the vaccination, which has the H1N1 strain in it.

But doctors and pharmacists agree -- the vaccination is still worth it.

"The hope is that the severity and length of the illness will be less after being vaccinated," Morrissey said.

"It's still 70-75 percent effective, so I recommend getting it now," Roland said.

There have been 945 deaths from the flu in Missouri in the last year.  That is fewer deaths than this time last year.