PHILADELPHIA (CBS) - A new study in the Canadian Medical Journal might be giving us our best evidence to date that flu shots are helpful when given to young children.

Back in the 2006-2007 flu season the government expanded the age of children vaccinated to four years old. We have had many changes in recommendations over this period but, as a result of that change, researchers compared flu-related emergency room visits in Children’s Hospital in Boston to Montreal Children’s Hospital in Canada, where shot recommendations were not expanded. There was a drop in visits by 2-to-4 year olds.

That is not surprising but it is very interesting that there was also an 11 to 14 percent decrease in visits by surrounding age groups at Children’s Hospital in Boston compared to Montreal Children’s Hospital. The drop in surrounding age groups could have been related to the stop in spread of the flu from the vaccinated 2 to 4 year olds.

Reported By Dr. Brian McDonough, KYW Newsradio Medical Editor