4 yo ds has had a run of bad luck with health recently;recovered well from a tonsillectomy only to be hit by a nasty d&v bug. It's been a hard year health wide for him and he is just skin n'bone and very pale. Typically the pox is doing the rounds at his school and the schools my husband and I both work in. I want his little body to have a break from more illness, and I want him to build an appetite again! I suspect he is pretty vulnerable to catching things at the moment and I fear would not have an easy time of it if he did catch it. Should I vaccinate just to stop any chance of a bad attack?