Tylenol reduces effectiveness of vaccines in babies?

A new study published in The Lancet, led by military and government scientists in the Czech Republic, has found that Tylenol (aka acetaminophen, paracetamol), when administered right after an immunization shot, can slightly reduce the effectiveness of vaccines in young babies (9-16 weeks old). Acetaminophen is widely recommended as an analgesic for babies, and it seems to be common practice for parents to give their babies acetaminophen right after they get their shots to prevent fever and fussiness. Fever after a vaccine is pretty common -- it's the body's immune response -- but apparently, curbing the fever also reduces the immune response and the amount of antibodies that are produced. In fact, antibody levels remained significantly lower even after the babies got their booster shots at 12-15 months old.

Doctors from the U.S. Centers For Disease Control and Prevention note that even with the use of acetaminophen, more than 90% of the babies achieved protection from the vaccines after the booster dose, but they believe that the consistency of findings from other studies suggests that routine use of fever-lowering medicines during immunization may not be recommended.