As far as I know, there is no waiting period. You can even get a flu shot with other vaccinations. However, flu shots aren't known for being very effective. They are manufactured sop far in advance that the current flu strain is not the same as the one in the vaccine. Some people say that a flu shot makes flu symptoms less bad if you get it, but from my own experience and from just about everyone I've talked to, getting a flu shot pretty much guarantees you get the flu, and it's bad.You're better off using natural remedies to strengthen your, and your children's, immune systems and to fight cold or flu symptoms. Vitamin D, vitamin C, zinc, echinacea, and goldenseal (unless you're pregnant, and then goldenseal isn't safe) are all great for the immune system, as are natural yogurt and probiotics. If you get sick, take these remedies, as well as something like Zicam. I took it when my kids and husband got sick and I didn't get sick at all. I also used the EmergenC immune formula.