"Get your kids their flu vaccines now, pediatricians advise."
“With the exception of children less than 6 months of age, everybody should go out and get their influenza vaccine as soon as the influenza vaccines are available,” Dr. Michael Brady of Nationwide Children's Hospital and chairman of the Committee on Infectious Diseases for the Academy told NBC News...
It also takes a week or so for the flu vaccine to take effect and provide full protection.
“Most time, flu in the U.S. peaks in January, February, sometimes into March,” Brady said. “If people go get their vaccines as soon as their provider has them available, they should feel comfortable that they'll have protection for the whole flu season.”
There are two potential problems with getting flu shots early. First, vaccine protection decreases rapidly and those who are older or have less robust immune systems may have lost protection before the flu appears.
Second, frequently the vaccine does not protect against the strains that cause disease each season. But until flu appears, we don't know if the vaccine will protect. By waiting to vaccinate until late fall, you will know whether the flu shot is likely to provide any benefit at all against that year's flu strains.