With influenza season right around the corner, public health officials and manufacturers continue working to improve the effectiveness of the flu shot. Last year's shot was only 36 percent effective according to the Center for Disease Control and Prevention.
"It's always a guessing game," said Dr. John Hallberg of the University of Minnesota. "People who make the vaccines are trying to figure out what are the strains that are going to be circulating."
This year, clinics are providing new vaccines made up of four strains and higher antigen doses.
"We're not just giving the higher dose to older people, we're giving it to everyone," Hallberg said.
Although the vaccine is still not foolproof, it beats the alternative.
"Thousands and thousands of people die from influenza every year in this country," Hallberg said. "Symptoms like a sore shoulder are not that big of deal compared to influenza itself."