I have a 5yr old son, he has asthma pretty bad - so we get him flu shot every year - started when he was 2.... He is pretty rough & tough little guy and he don't even flinch when he gets his shot. I think it may just depend on your child..... I give him Tylenol a dose before his shot and a couple doses after and he's never been bothered by it. But for my other 2-kids I've never gotten them shots. - hard call!!!!