vaccination why you need second dose
The second dose should be given at least 28 days after the first dose. The first dose âprimesâ the immune system; the second dose provides immune protection. Children who only get one dose but need two doses can have reduced or no protection from a single dose of flu vaccine.If your child needs the two doses, begin the process early.he first dose âprimesâ the immune system; the second dose provides immune protection. Children who only get one dose but need two doses can have reduced or no protection from a single dose of flu vaccine. If your child needs the two doses, begin the process early.