Tylenol May Reduce Vaccines’ Effects

Most parents (including this one) would give a child Tylenol right after a routine vaccination. But that may not be such a good idea, according to a new study published in Lancet.

Giving infants Tylenol (generic – paracetamol) to prevent fever after a vaccination may reduce the vaccine’s effectiveness, a new research has found.

Parents usually give Tylenol before or immediately after a routine shot so the child does not get a fever. However, this may not be a good idea since fever is usually the body’s natural immune response to the vaccine. In a Czech study published in Lancet (online October 16), 459 infants were followed after routine vaccination against polio, pneumonia, meningitis, whopping cough, tetanus and other childhood diseases. Half of the babies were given paracetamol within the first day after vaccination. These children did not develop fever, but their levels of antibody were lowered than the group who were not given any pain killers. The antibody levels remained low even after booster shots were given twelve months later.

An editorial wrote that the study makes "a compelling case against" routine use of fever-lowering medicines during immunization. The study did not look at whether immunity was lowered when paracetamol was given after fever developed, so there is no way to tell if the vaccine was as effective in this case.

This new finding is so relevant in light of the seasonal flu and the H1N1 vaccinations. So what’s a parent to do in case fever does develop?

(I found the article that mentioned this study at Associated Press/Yahoo! and I assumed the writer was given advance notice before the article is published tomorrow. Once I get a copy of the paper and the editorial, I will update this post. Maybe we can find some guidelines about what to do in case fever does develop. STAY TUNED.)

Image: Zuma Press