Being a first time grama is exciting, but you have to know your boundries. Allow the parent's to make decisions regarding the baby and his medical issues. It sounds like you want to be involved and that is good, but keep your distance.
A newborn comes into the world with a low immune system and is unable to fight off infections and diseases by themselves. There fore they are given a series of immunizations thru out their first 2 years of life, then a booster each year there after. These immunizations help fight many childhood diseases, like, whooping cough, diptheria, pertussis, measals, mumps, rubella.....etc. They are an important part of the baby's early years and can eliminate any possible medicals issues in the future. A child MUST be current on ALL of their shots before they can begin kindergarten or Pre school.
Mant parent's, whether it is a religious beleif or not, decide not to have their baby's immunized, this is dangerous and unnecessary. Children actually become very sick and die because his/her parent's decided not to have them immunized. It is not done out of spite, it's what they beleive and what their religion calls for.
As far as side effects...some baby's sail thru this while other's don't. Some will develop a high fever after a shot, that is why tylenol is given an hour before the scheduled appt. Swelling and redness at the injection site is also common, tylenol will help that as well. A rash may appear all over the baby's body, this is a severe reaction and the doctor should be called. The baby will sleep several hours after, this is normal, they may loose their appetites for a few days, this is also normal. If the injection was given in the muscle of the baby's leg, you will notice that the baby has a hard time moving the leg and may cry when that site is touched, this is normal. The person giving the shot sometimes hit's the muscle, but they try to avoid that as much as possible. There is also a liquid immunization given by mouth at the same visit. This is included in the first visit when the baby is given the 3 in 1, which is, DPT, meaning...Diptheria, Pertussis and Tetnus.
Many baby's will get their shot, let out one good scream, and life goes on as normal, it may not affect them in any way at all and one wouldn't even know that he/she had their shots that day.
So...relax grama. I know it's exciting, i have 5 grandsons, with one on the way. 6 grandson's! But remember to give advice when it's asked for and don't offer up those old wives tales, tho some may be useful. I have learned to watch and listen and the parent's will come to you for advice.