There is recent evidence that immunizations may work better if acetaminophen (Tylenol) or ibuprofen (Motrin, Advil) is NOT given prior to immunizations. In the past, many parents and health care providers have routinely given acetaminophen to children before they receive their vaccinations to counteract any mild fever and achiness they may experience.
Only a small percentage of children experience fever or achiness following immunizations. So it is now recommended that children be given acetaminophen or ibuprofen only if they become uncomfortable or become fussy as the result of a mild temperature or achiness AFTER they receive immunizations.
The Latest Research
We now know that a fever is one sign that our bodies are generating an immune response. A recent study indicated that acetaminophen taken before vaccines could possibly reduce that immune response and thus make the vaccines less effective. This means that a fever could make the vaccines work better! Keep in mind that this was just one study, and it did not look at other fever-reducing medications such as ibuprofen.
Probably the best advice is to wait and see how your child reacts to the immunizations. Many children are not troubled by a mild vaccine-related fever. If that is the case, the fever is possibly a good thing, and acetaminophen or ibuprofen isn’t necessary. If, however, your child is feeling sick (or is excessively fussy) after receiving vaccines, it is then worth considering giving him or her acetaminophen or ibuprofen.