Vaccine 29 (2011) 1390–1394 Contents lists available at ScienceDirect Vaccine journal homepage: www.elsevier.com/locate/vaccine Evaluation of the reliability, validity and practicality of 3 measures of acute pain in infants undergoing immunization injections Anna Taddio a,b,∗ , Mary-Ellen Hogan a,b , Paul Moyer a , Angela Girgis a , Sandra Gerges a , Linda Wang a , Moshe Ipp c,d a Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada M5S 3M2 b Child Health Evaluative Sciences, The Hospital for Sick Children, Ontario, Canada c Department of Paediatrics, The Hospital for Sick Children, Ontario, Canada d Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 3M2 article info Article history: Received 9 November 2010 Received in revised form 11 December 2010 Accepted 15 December 2010 Available online 30 December 2010 Keywords: Pain assessment Reliability Validity Practicality Infant Immunization abstract There is a need to identify a primary measure of infant pain that can be used to assess pain in infants undergoing vaccine injections in order to facilitate vaccine outcomes research. The aim of the present study was to determine the reliability, validity and practicality of 3 measures of acute pain in infants; the Modified Behavioural Pain Scale (MBPS), Neonatal Infant Pain Scale (NIPS), and Face Legs Activity Cry Consolability Scale (FLACC). Five raters rated pain from videotapes in 120 infants aged 2–6 months undergoing vaccine injections that participated in a randomized controlled trial designed to compare pain responses between two vaccines, DPTaP-Hib vaccine and PCV vaccine. Inter-rater reliability coefficients for baseline and vaccine injections were all greater than 0.85. Cronbach’s alpha ranged from 0.83 to 0.94. Construct validity was demonstrated for all measures by vaccine injection scores that were higher (p < 0.001) than baseline scores and by PCV scores that were higher than DPTaP-Hib scores. Concurrent validity was demonstrated by bi-variate correlation coefficients that ranged from 0.84 to 0.92. Intra-rater reliability coefficients for scores obtained after a single viewing (simulating real time assessment) versus multiple viewings were ≥0.96. All measures demonstrated a significant difference in pain scores between the more painful (PCV) and less painful (DPTaP-Hib) vaccine for scores obtained after a single viewing. The majority of raters (4 out of 5) preferred the MBPS. Together, these results provide preliminary support for the MBPS as the primary outcome of pain during vaccine injections in infants. © 2010 Elsevier Ltd. All rights reserved. 1. Introduction Immunization is considered one of the most significant medical achievements of all time. Since immunization programs have been implemented, there has been a substantial reduction in morbidity and mortality caused by infectious diseases. Most immunizations, however, require a painful needle injection or ‘shot’ [1]. Assess- ment and documentation of pain during ‘shots’ is considered an important aspect of vaccine outcomes research as it allows for comparison of pain across settings, conditions and/or surveillance systems. At present, however, there is no uniform definition of pain during vaccine injections, precluding standardized assessment and reporting of pain as an adverse event following immunization (AEFI). ∗ Corresponding author at: Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario, Canada M5S 3M2. Tel.: +1 416 978 8822; fax: +1 416 978 1833. E-mail address: anna.taddio@utoronto.ca (A. Taddio). The Brighton Collaboration (http://brightoncollaboration.org), a global vaccine safety effort, is currently developing a case definition of pain that is intended to standardize reporting of pain in vaccine trials and safety monitoring worldwide. Rec- ognizing that the manner in which pain is expressed and communicated is different for individuals of different ages, the guideline will specify developmentally appropriate pain rat- ing scales for use in individuals of all ages, from infants to adults. At present, observations of pain behaviours are considered the optimal method of infant pain assessment. Recent reviews, how- ever, point to the presence of dozens of available rating scales [2,3]. A single practical and valid tool that clinicians perform- ing vaccine injections can use would facilitate pain assessment and allow for standardized reporting across clinical settings. The current study sought to address this knowledge gap. The specific objectives were to investigate the reliability, validity and practicality of 3 observational measures of acute pain for the assessment of pain in infants undergoing vaccine injec- tions. 0264-410X/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.vaccine.2010.12.051