Lidocaine, Not Sucrose, Relieved Some Pain in Infant Vaccination

In a randomized controlled trial designed to compare the effectiveness of additive pain interventions during routine infant vaccinations in the first year of life, only topical liposomal lidocaine provided consistent analgesia.¹ Results were published ahead of print December 12 in CMAJ: Canadian Medical Association Journal.

The study examined the impact on infant distress levels of different pain interventions when layered together, starting from the simplest to the most complicated in terms of implementation. A total of 352 infants and their parents, recruited from 3 pediatric outpatient clinics in Toronto, took part.

Participants were randomized to receive one of 4 interventions: placebo control; a brief video instructing parents about infant pain management; the pain management video plus orally-administered sucrose (sugar water); or the video plus sucrose plus topical liposomal lidocaine. The primary outcome was infant distress as determined by the Modified Behavioural Pain Scale (MBPS), a multidimensional pain assessment tool validated for infant vaccination pain. The MBPS incorporates 3 domains of infant behavior — facial grimacing, crying, and body movements.

“We hypothesized that increasing levels of pain management would lead to increasing pain relief,” wrote the investigators. However, in contrast to results from previous studies, the sucrose and video interventions proved no more effective than placebo. The group that received the video plus sucrose plus lidocaine had a mean (± standard deviation) needle score of 6.3 (± 0.8) vs. 6.7 (± 0.8) for each of the other groups.

Summary & Clinical Applicability

Anna Taddio, PhD, told Clinical Pain Advisor that despite their effectiveness in reducing vaccination pain, topical anesthetics such as liposomal lidocaine are infrequently used for that purpose.

“We need to do a better job teaching parents and health care providers about the importance of mitigating pain in children,” she said, noting the erroneous yet common belief that the pain felt during vaccination is of such short duration that it does not need to be addressed. “Negative experiences with pain can increase sensitivity to future pain, and contribute to negative attitudes about immunization and noncompliance with immunization and other medical interventions that involve needles. This negatively impacts the health of individuals themselves and society at large.”

Dr Taddio also pointed out the need to develop less painful vaccines. “Even with the use of the topical anesthetic, there was still pain in infants in the study. That is, pain was reduced but not eliminated. Ideally we should be preventing the pain that is caused by the procedure.”

Limitations & Disclosures

Dr Taddio declared a research grant from Pfizer, and study supplies from Natus and Ferndale. The other authors declared no conflicts of interest.

Reference

Taddio A, Pillai Riddell R, Ipp M, et al. Relative effectiveness of additive pain interventions during vaccination in infants. CMAJ Can Med Assoc J J Assoc Medicale Can. December 2016. doi:10.1503/cmaj.160542.