First major study finds that Tylenol may interfere with vaccines

New research has indicated that giving babies Tylenol when they get childhood vaccinations to help prevent fever, may cause the shots to be less effective.

This is the first major study that links decreased immunity to the use of fever-reducing medicines. Even though the effect was diminutive, and most kids will still receive adequate protection from vaccines, the results do make an important argument against regularly giving Tylenol right after a vaccination according to the U.S. Centers for Disease Control and Prevention. An editorial was written along with the study, which was published in the October 16 issue of the British medical journal Lancet.

The study focused only on the preventive use of Tylenol – not whether it is safe to use after a fever develops.

Tylenol and its generic relative, acetaminophen, is routinely suggested to alleviate pain in babies. It is commonly given by parents right after or before a shot to help prevent a fever or fussiness, and some doctors even support this. The CDC’s vaccine advisory panel claims that it is a customary thing to do for children who are at high risk for seizures, which are often set off by fevers.

All this said, getting a fever after a vaccine isn’t really always a bad thing. It’s a natural response from the body. The new study has found that suppressing fever, particularly the very first time an infant gets a vaccine, appears to reduce the immune response and the number of protective antibodies that are created.

The study was carried out by military and government scientists in the Czech Republic and was performed at ten medical centers in that Eastern European country. Involved in the study were 459 healthy infants ranging in age from 9 to16 weeks old, who were receiving vaccines against polio, pneumonia, meningitis, whooping cough, tetanus, hepatitis and other early life diseases.

During the first day after the vaccination, half of the participants in the study were prescribed three doses of Calpol or paracetamol, which is a brand similar to Tylenol that is sold in Europe. Nothing but the vaccine was given to the other group.

The group that was given the drug showed lower rates of protective antibody levels from several vaccines. Another disturbing finding was that these lower levels stayed lower in this group, even after booster vaccines were given when the babies were 12 to 15 months old.

Then, the researchers analyzed 10 other vaccine studies and discovered evidence that using Tylenol to prevent fevers at the time of vaccination may lessen the immune system response rates. Similar results may or may not be true when using the tylenol or it’s generic to treat fevers after they develop.

Belgium based GlaxoSmithKline Biologicals sponsored the research. They make all the vaccines that were used in the study. Some authors have monetary ties with the company and Glaxo played a significant part in the results that were reported.