Never give Tylenol before shots. You may decrease your baby’s (or child’s) immune response to the shot for no reason. It’s okay for your baby to have a fever. It’s a safe and normal response to immunization. Tylenol or its generic twin, acetaminophen, is widely recommended as a painkiller for babies. Many parents give it right before or after a shot to prevent fever and fussiness, and some doctors. Any doctor i have ever been to said to give them tylenol 20 minutes before they get their shots. So why would they say that if it reduces the effectiveness of the vaccine thats just stupid. For most parents - even the strongest believers in the benefits of vaccines - anticipating how their newborns' facial expressions will turn from curious to shock before they burst into tears from the needle stick, can make the next well-baby check-up something they would love to skip. Bring the Tylenol with you to his visit. As soon as your baby is weighed, you can ask the nurse how much Tylenol to give him, based on his weight, and give it to him right then. 30 minutes before is okay, longer than that doesn't make a difference. Giving babies Tylenol to prevent fever when they get childhood vaccinations may backfire and make the shots a little less effective, surprising new research suggests. yes,i belive in giving them tylenol before shots.it gives you the edge because normally they run a little fever.the fever was never bad because i always gave them tylenol 30 minutes before their shots,and it helps with the pain too! Oct. 15, 2009 - Acetaminophen, the active ingredient in Tylenol, weakens infants' immune responses to vaccines, a compelling new study suggests.