Our objective was to develop a clinical practice guideline, based on systematic reviews of the literature, as interpreted by experts, to assist clinicians in managing procedure-related pain and distress among children undergoing vaccine injections. The scope was limited to acute (immediate) pain and distress at the time of vaccine injection in children 0 to 18 years of age. We did not consider the management of delayed-onset pain occurring in the hours or days after the injection. Health care providers and researchers often use the term "distress" to refer to the combination of pain and anxiety or fear experienced by children before and during painful medical procedures. For the purposes of this guideline, we considered distress and pain together, referring to the com - bination as "pain." Topical anesthetics reduce pain associated with needle pro - cedures, including venipuncture and intravenous cannulation. 57 Our systematic review12 included 10 trials that evaluated the effects of topical anesthetics in a total of 1156 infants and children (up to 15 years of age).17,58-66 Of the seven studies that compared topical anesthetics with placebo cream or patch, six showed that these drugs were effective in reducing pain.58-63 In the negative study,64 older children (11-15 years) were enrolled. In addition, there were certain methodologic limitations that might explain the results, including use of an insensitive pain assessment method and rating of pain performed with the help of the physician. In two trials that included a no-treatment (control) group,65,66 topical anesthetics were ineffective, and in another trial, they were effective.17 Again, these results might be explained by some methodo - logic limitations, including lack of blinding and nurses' interactions with the no-treatment (control) group, which equalized responses between the groups; increased anticipatory anxiety because of a one-hour application time; and close proximity of peers (children from the same classroom) influencing self-reported pain ratings. We concluded that topical anesthetics are effective for reducing vaccination pain. We found no evidence of interference with vaccine immunogenicity for measles-mumps-rubella vaccine or the vaccines for diphtheria, tetanus, acellular pertussis, poliovirus, Hemophilus influenzae type B and hepatitis B.59-61 Here, we provide specific guidance regarding the method of pain assessment for children of different ages, according to our consensus interpretation of the vaccination literature, considering the validity and feasibility of currently available pain assessment methods. For preverbal children and infants, adult observers (parents, health care providers or both) are required to assess pain. We recommend that health care providers use one of two observational tools: the Modified Behavioural Pain Scale96-98 (for infants up to 18 months of age) or the Face Legs Activity Crying Consolability scale99 (for infants over 18 months of age). Parents should use a global rating scale (e.g., numerical rating scale or visual analogue scale). Verbal children can be asked to self-report pain100 using age-appropriate techniques: either the Poker Chip tool101 (3 to 6 years of age), the Faces Pain Scale - Revised102 (4 to 16 years of age) or a numerical rating scale103,104 (9 years of age and older). We encourage health care providers to document the strategies used to reduce acute pain at the time of vaccine injection, as well as the child's pain score.