Use of lidocaine-prilocaine patch to decrease intramuscular injection pain does not adversely affect the antibody response to diphtheria-tetanus-acellular pertussis-inactivated poliovirus-Haemophilus influenzae type b conjugate and hepatitis B vaccines in infants from birth to six months of age

Background. Topical lidocaine-prilocaine (EMLA) effectively decreases the pain associated with minor procedures including immunization, although the effect on the antibody response to diphtheria-tetanus-acellular pertussis-inactivated poliovirus-Haemophilus influenzae type b conjugate (DTaP-IPV-Hib) and hepatitis B vaccines has not been assessed. Objective. To measure the antibody response to DTaP-IPV-Hib and hepatitis B vaccines; to measure pain reduction associated with the use of the lidocaine-prilocaine (EMLA) patch; and to assess safety by comparing adverse reactions. Participants and setting. One hundred nine healthy 6-month-old infants (Part A of study) and 56 healthy infants birth to 2 months of age (Part B of study) undergoing primary immunization with DTaP-IPV-Hib and hepatitis B vaccines in an ambulatory setting. Design and interventions. Two center, randomized, double blind, controlled trial of EMLA patch or placebo before DTaP-IPV-Hib and hepatitis B immunization. Antibody titers measured at 0 to 2, 6 and 7 months. Outcome measures. The primary outcome measure was the antibody response to diphtheria, tetanus, pertussis antigens, Haemophilus influenzae type b and hepatitis B by enzyme immunoassay; and poliovirus 1, 2 and 3 by neutralization. The secondary outcomes were pain scores by the Modified Behavioral Pain Scale and drug- and vaccine-associated adverse events collected with a parent diary and structured questionnaire. Results. There was no difference in the antibody response between the EMLA- and placebo-treated groups as assessed by geometric mean antibody titers, rates of seroconversion or the proportion of participants achieving protective or positive antibody titers postimmunization. At the 6-month visit, EMLA recipients had less pain after immunization (total pain score, 6.75 vs. 7.35; P = 0.005; pain score increase, 3.99 vs. 4.74; P = 0.004) than did placebo recipients. Skin pallor and erythema at the patch application site were more frequently reported after EMLA use. Rates of vaccine-associated adverse events were similar in the two groups. Conclusions. The EMLA patch has no adverse effect on the antibody response to the vaccine antigens, is effective in reducing pain associated with DTaP-IPV-Hib and hepatitis B immunizations and does not result in any significant or unexpected adverse reactions.