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Tylenol and Vaccinations


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The site administrator for OCDParenting on yahoo groups posted this article about how Tylenol may interfere with the effectiveness of vacinations. I thought some of you might find this interesting...


This study will appear in the medical journal "Lancet" tomorrow.


Prophylactic Acetaminophen Reduces Immunogenicity of Childhood Vaccines



Children given acetaminophen with vaccinations have lower rates of fever in response, but the vaccinations produce a lower immunogenicity, reports a Lancet




Researchers, including some from the sponsoring vaccine manufacturer, followed over 400 infants receiving primary and booster immunizations. Half received

acetaminophen via suppository in three doses over the first 24 hours after vaccination, and half received no prophylaxis.



The percentage of children with a temperature of 38 degrees C or higher was significantly lower in the acetaminophen group by some 40% to 50% both at

primary and booster immunizations. However, vaccine immunogenicity was lower in the acetaminophen group — significantly so for some antigens, e.g., all 10

pneumococcal serotypes after the primary immunization. The authors hypothesize that the effect could result from acetaminophen's preventing inflammation.



Over 95% of all children had seroprotective antibody levels, but researchers argue that antipyretics "should ... no longer be routinely recommended" with

vaccination. Editorialists agree, calling the case "compelling."



The Lancet, Volume 374, Issue 9698, Pages 1339 - 1350, 17 October 2009 <Previous Article|Next Article>doi:10.1016/S0140-6736(09)61208-3Cite or Link Using

DOIEffect of prophylactic paracetamol administration at time of vaccination on febrile reactions and antibody responses in children: two open-label, randomised

controlled trials


Original Text

Prof Roman Prymula MD a , Prof Claire-Anne Siegrist MD b, Roman Chlibek MD a, Helena Zemlickova MD c, Marie Vackova MD a, Jan Smetana MD a, Patricia Lommel

BScb d, Eva Kaliskova MD e, Dorota Borys MD d, Lode Schuerman MD d




Although fever is part of the normal inflammatory process after immunisation, prophylactic antipyretic drugs are sometimes recommended to allay concerns of

high fever and febrile convulsion. We assessed the effect of prophylactic administration of paracetamol at vaccination on infant febrile reaction rates and vaccine responses.



In two consecutive (primary and booster) randomised, controlled, open-label vaccination studies, 459 healthy infants were enrolled from ten centres in the

Czech Republic. Infants were randomly assigned with a computer-generated randomisation list to receive three prophylactic paracetamol doses every 6—8 h

in the first 24 h (n=226) or no prophylactic paracetamol (n=233) after each vaccination with a ten-valent pneumococcal non-typeable Haemophilus influenzae

protein D-conjugate vaccine (PHiD-CV) co-administered with the hexavalent diphtheria-tetanus-3-component acellular pertussis-hepatitis B-inactivated

poliovirus types 1, 2, and 3-H influenzae type b (DTPa-HBV-IPV/Hib) and oral human rotavirus vaccines. The primary objective in both studies was the

reduction in febrile reactions of 38·0°C or greater in the total vaccinated cohort. The second objective was assessment of immunogenicity in the

according-to-protocol cohort. These studies are registered with ClinicalTrials.gov, numbers NCT00370318 and NCT00496015.



Fever greater than 39·5°C was uncommon in both groups (after primary: one of 226 participants [<1%] in prophylactic paracetamol group vs three of 233 [1%] in

no prophylactic paracetamol group; after booster: three of 178 [2%] vs two of 172 [1%]). The percentage of children with temperature of 38°C or greater after

at least one dose was significantly lower in the prophylactic paracetamol group (94/226 [42%] after primary vaccination and 64/178 [36%] after booster vaccination) than in the no prophylactic paracetamol group (154/233 [66%] after primary vaccination and 100/172 [58%] after booster vaccination). Antibody geometric mean concentrations (GMCs) were significantly lower in the prophylactic paracetamol group than in the no prophylactic paracetamol group after primary vaccination for all ten pneumococcal vaccine serotypes, protein D, antipolyribosyl-ribitol phosphate, antidiphtheria, antitetanus, and antipertactin. After boosting, lower antibody GMCs persisted in the prophylactic paracetamol group for antitetanus, protein D, and all pneumococcal serotypes apart from 19F.



Although febrile reactions significantly decreased, prophylactic administration of antipyretic drugs at the time of vaccination should not be routinely recommended since antibody responses to several vaccine antigens were reduced.



GlaxoSmithKline Biologicals (Belgium).

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Yeah, that's what I found interesting about this article. This site has so many kids failing pneumo titer tests and it makes you wonder - are they immuno-deficient because of some genetic factor or simply because the pediatrician suggested tylenol for comfort...

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