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.