Prophylactic paracetamol at the time of infant vaccination reduces the risk of fever, but also reduces antibody response
- Correspondence to S Songül Yalçin
Faculty of Medicine, Department of Pediatrics, Hacettepe University, Samanpazari, Ankara, Turkey
Childhood immunisations are often associated with local and systemic adverse reactions. Although usually benign, mild and self-limited, adverse events following childhood immunisation can result in discomfort in the child and family, and the adverse reaction to a previous vaccination is one of the main reasons for non-immunisation of children.1 The Advisory Committee on Immunization Practices and the American Academy of Pediatrics recommend prophylactic use of antipyretics in infants and children at high risk for seizures. A previous review2 showed that the use of prophylactic paracetamol and ibuprofen may reduce the incidence of adverse reactions only in infants aged 2–6 months receiving the DTPw (diphtheria–tetanus–whole cell pertussis) vaccine. However, a study by Yalçin and colleagues3 showed that administration of paracetamol along with DTPw vaccine or 2 h after vaccination does not affect the occurrence of febrile responses following booster vaccination, resulting in the unnecessary use of analgesics.
Prymula and colleagues were first to examine vaccine reactogenicity and immunogenicity carefully with a current paediatric vaccine regimen (a 10-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) in a randomised controlled clinical trial. They showed that prophylactic paracetamol was effective for reducing mild to moderate febrile reactions; however, it also reduced antibody responses to several vaccine antigens after primary vaccination and boosting. A reduction in the primary antibody responses to each of the 10 pneumococcal conjugate vaccine serotypes and to Hib polysaccharide, diphtheria, tetanus and pertactin antigens was detected in this study. Also, post hoc analysis showing similar effects for children with and without fever revealed the significance of prophylactic paracetamol in vaccine immunogenicity. One strength of this study was that a negative effect of paracetamol on immunogenicity was further supported by post hoc analyses from 10 previous trials, including 3700 participants who received primary vaccination of DTPa-HBV-IPV/Hib or DTPa-IPV/Hib and HBV, the licensed seven-valent pneumococcal conjugate vaccine (7vCRM), H influenzae type b, or H influenzae type b–Neisseria meningitidis serogroups C and Y conjugate vaccines and 700 children who received a booster dose of DTPa-HBV-IPV/Hib, 7vCRM, DTPw-HBV/Hib, or DTPw-HBV plus H influenzae type b, suggesting the greatest effect during the 24 h after immunisation. The study could have been strengthened if data had also been collected from children who were using prophylactic paracetamol after one of the priming doses at the first or the second or the third dose of DTPa-IPV/Hib to determine longevity of action.
The findings are relevant to paediatric practitioners and nurses who might prescribe or recommend paracetamol prophylaxis for vaccinated children. Prophylactic paracetamol and ibuprofen should be avoided in healthy children receiving vaccination.4 It is important to remind parents that the accessibility of over-the-counter analgesics does not mean that these products are safe for everyone. In addition, febrile reactions triggered by DTPa-based combination vaccines are milder than those elicited by DTPw. On the other hand, paracetamol and ibuprofen can be administered to treat adverse reactions to vaccines. Parents should be counselled to monitor infants and children for vaccine-related adverse reactions and to treat them if and when they occur.
Competing interests None.