One a baby has had hfmd is he immune to it or can they get it again?

It is possible that a baby can get hand foot and mouth diease again after getting it once. Like flu, there are different strains of hfmd, so the baby will not be immuned to the virus after having it once. It is also highly contagious since it can easily spread through body fluid. The first sign is usually fever (and not the rashes). Practice good hygiene to avoid catching it. My three-year-old nephew recently got it and my cousin went through a difficult week having to take care of him and trying hard to prevent his 10month old sister from getting it as well. She had to constantly wash hands and change clothes. Still, both her and the younger one fell prey to the virus. Hope you won't have to go through that too!