Ask the Experts: Pretreating with APAP for infant vaccines; maternal antibodies against influenza in breast-fed infants

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Question for our experts on reasons for/against pretreatment with acetaminophen (APAP) for infant vaccines.

Question. Why shouldn't we pretreat with acetaminophen (APAP) for infant vaccines?

Answer. A multicenter study in the Czech Republic randomized 459 infants to receive or not receive three prophylactic doses of acetaminophen (APAP) in the first 24 hours, then vaccinated the infants with pneumococcal vaccine, DTaP-HBV-IPV/Hib, and oral rotavirus. Although primarily looking at fever, the investigators surprisingly found that the antibody geometric mean concentration in the APAP group also was significantly lower for pertussis, pneumococcal, Hib, diphtheria, and tetanus following primary vaccination and for Hib, tetanus, and most of the pneumococcal serotypes following booster vaccination. One theory for this occurrence is a decrease in inflammatory response following APAP. However, the clinical significance of this is unknown because we do not know at what antibody level we have protection.


  • Pyrmula R, Siegrist CA, Chlibek R, et al. Effect of prophylactic paracetamol administered at time of vaccination on febrile reactions and antibody responses in children: two open-label, randomised controlled studies. Lancet. 2009;374:1339–50.

Question. How much of the influenza vaccine is passed on to a breast-fed infant?

Answer.  We do know that maternal antibodies against influenza are passed onto infants during pregnancy. I am not aware of specific influenza antibody studies in breast milk; however, antibodies are shared through breast milk, especially in the initial colostrum.

Stephan L. Foster, PharmD, FAPhA
Professor and Vice Chair
College of Pharmacy
University of Tennessee Health Sciences Center
APhA Liaison Representative to the Advisory Committee on Immunization Practices (ACIP)
CAPT (Ret) U.S. Public Health Service


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