The flu season starts in October, but the American Academy of Pediatrics recommends getting your child a vaccine sooner rather than later. For children six months to eight years old, two shots may be needed by the end of next month. Just one shot will do the trick for ages nine and up. Florida pediatrician Dr. Jean Moorjani says getting the shot early will provide the most protection during flu season. You won't be fully protected for about two weeks after you get the shot. What I say to patients is to try and get your appointment by Halloween. , Dr. Jean Moorjani, via 'USA Today'. The flu was responsible for killing 129 children during last year's flu season. According to 'USA Today,' the 2018-19 season put a record number of people in the hospital. It did not end until April, making it the longest flu period in over 10 years.