Background: The frequency of local vaccination reactions increases with successive doses of diphtheria-tetanus toxoids-acellular pertussis (DTaP) vaccine, and local reactions occur for the majority of children receiving the fifth DTaP vaccination. It is not known whether these reactions can be prevented with prophylactic use of acetaminophen or ibuprofen.
Methods: In this 3-group, randomized, blinded, controlled trial, 372 children were assigned randomly, in a 2:2:1 ratio, to receive 3 doses of acetaminophen, ibuprofen, or placebo. The first dose of study medication was administered within 2 hours before the fifth DTaP vaccination, and the remaining 2 doses were given at 6-hour intervals. The primary outcome measures included a local reaction with an area of redness or discoloration > or =5 cm in diameter on the evening of or during the 2 days after vaccination, an increase in mid-limb circumference of > or =2 cm on the evening of or during the 2 days after vaccination, and a persistent local reaction, defined as an area of redness or discoloration present on the third day after vaccination.
Results: Local reactions with a > or =5-cm area of redness or discoloration were reported for 35% of children in the placebo group, compared with 33% of children in the acetaminophen group and 37% of children in the ibuprofen group. There was also no significant difference between the placebo and treatment groups in the proportions of children with a > or =2-cm increase in mid-limb circumference or with a persistent local reaction.
Conclusions: We did not find evidence that prophylaxis with acetaminophen or ibuprofen offers a clinically significant benefit in prevention of local reactions to the fifth DTaP vaccination.