BACKGROUND. Immunization pain is a global public health issue. Despite an abundance of data that demonstrate the efficacy of local anesthetics for decreasing immunization pain, their adoption in practice has not been determined. Our objective was to evaluate analgesic use during childhood immunization.
PATIENTS AND METHODS. We used a cluster-sampling survey of pediatricians in the greater Toronto area (who administer immunizations) and multiparous women. By using a self-administered survey, pediatricians reported frequency of analgesic use in their practice for 2 phases of immunization: injection (needle puncture and vaccine administration) and postinjection (hours to days postvaccination). By using an interviewer-administered face-to-face survey, mothers reported analgesic practices for their children.
RESULTS. Of 195 eligible pediatricians, 140 (72%) responded. During the injection phase, 58% rarely or never used analgesics compared with 11% for the postinjection phase. During injection, the local anesthetics lidocaine-prilocaine and tetracaine were used at least sometimes in 12% and 2% of the practices, respectively, whereas acetaminophen and ibuprofen were used in 81% and 46%, respectively. Postinjection, acetaminophen and ibuprofen were used in 89% and 56% of practices. Of 257 eligible mothers, 200 (78%) participated. During injection, analgesics were used in 25% of immunizations (acetaminophen [87%], ibuprofen [7%], and lidocaine-prilocaine [6%]). Postinjection, analgesics were used in 33% of immunizations (acetaminophen [86%] and ibuprofen [14%]).
CONCLUSIONS. A minority of pediatricians and mothers use topical local anesthetics during childhood immunization despite evidence to support their use. Oral analgesics are used more commonly, but this practice is not consistent with scientific evidence. Knowledge-translation strategies are needed to increase the use of local anesthesia.
Childhood immunizations are traumatic for children, their families, health care workers, and society at large.1 In addition to causing acute pain, repeated immunizations lead to preprocedural anxiety because of conditioning,2 hypersensitivity to future painful procedures,2,3 and avoidance of medical care because of “blood-injection-injury phobia.”4,5 Parents and health care workers are also stressed when witnessing pain being inflicted on children and are concerned about adverse effects of pain in children and themselves.6–12 Some parents become noncompliant with vaccine administration,13 which contributes to the risk of resurgence of vaccine-preventable disease.10
It is essential that analgesic strategies be adopted in clinical practice to manage childhood immunization pain. Immunization consists of 2 distinct phases that may be amenable to analgesia: the injection phase (needle puncture and vaccine administration) and postinjection phase (hours to days postvaccine administration). For the injection phase, there is ample evidence to support the routine use of topical local anesthetics (ie, lidocaine-prilocaine 5% cream and tetracaine 4% gel) for reducing pain.14–19 Conversely, there is no evidence to support use of oral analgesics (acetaminophen and ibuprofen) for injection pain.20,21 Postinjection, evidence is lacking for topical local anesthetics whereas there are conflicting data for oral analgesics.22–24 Currently, there is an absence of information on the frequency of analgesic use in clinical practice, and it is undetermined whether pain is being optimally managed. The objectives of this study were to survey both physicians and mothers about current analgesic practices for immunization pain in children.
We surveyed a cluster sample of pediatricians and mothers in the greater Toronto area (GTA) regarding analgesic practices during routine childhood immunization. The GTA is the most populated metropolitan area in Canada, with over 5.7 million inhabitants, and is the seventh-largest metropolitan area in North America. For pediatricians, we used a mailed, anonymous, self-administered questionnaire. For mothers, we used an interviewer-administered face-to-face questionnaire. Both questionnaires were designed in accordance with published guidelines.25 After determination of face and content validity, questionnaires were pretested on a sample of 10 volunteers for each one. Both questionnaires consisted mainly of closed-choice, categorical response questions regarding analgesic practices, analgesics used, nonpharmacologic strategies, attitudes and beliefs, and respondent attributes.26,27 For pediatricians, questions regarding analgesic use in their practice were answered by using categorical responses or 6-point ordinal scales (1, always [100%]; 2, almost always [75%–99%], 3; usually [50%–74%]; 4, sometimes [25%–49%]; 5, rarely [1%–24%]; and 6, never [0%]). Mothers reported on analgesic use (yes/no) for the most recent immunization in their previous child(ren). Information was gathered for up to 3 children.
We used the Canadian medical directory (2005) to identify all nonretired pediatricians practicing in the GTA and screened them for eligibility. A research assistant contacted each pediatrician's clinic to determine whether the pediatrician administered immunizations in his/her practice. If so, the clinic representative was informed that a survey would be mailed to the pediatrician. Questionnaires were mailed between August 2005 and October 2005, accompanied by a cover letter and self-addressed stamped envelope. All surveys were numbered with a unique identifier to track return rate. Surveys were issued up to 3 times if no response was obtained within 6 to 8 weeks between mailings, and data collection stopped 12 weeks after the third mailing.
We interviewed women hospitalized after childbirth at Mount Sinai Hospital, Toronto, Ontario, between December 2005 and August 2006. This hospital provides medical care for patients in the GTA. We included multiparous women who delivered healthy infants and had ≥1 child at home. Two trained research assistants performed interviews. Interrater reliability was evaluated on a random subsample of 20 participants (intraclass correlation coefficient: 1.0; P < .001). The study was approved by the research ethics boards of the Hospital for Sick Children, Mount Sinai Hospital, and the University of Toronto.
Sample-Size Calculation and Statistical Analyses
The primary outcomes were the frequency of analgesic use for 2 phases of immunization: the injection phase (needle puncture and vaccine administration) and the postinjection phase (hours to days postvaccine administration). The sample size for pediatricians was based on an estimation of 250 issued surveys with at least 50% response rate (≥125 returned surveys). That sample size provided a precision of 10%.28 For mothers, the sample size was similarly set at 250 interviews; however, it was later reduced to 200 to match the number of pediatrician surveys issued (see “Results”).
Data were analyzed descriptively and presented as frequency (percent), median (centiles), or mean (SD). Pediatrician-reported frequency of analgesia administration during and postinjection was correlated with physician gender, years of experience, type of practice, number of immunizations administered per week, rating of pain during immunization (using a 10-point scale, where scores ranged from 0 to 10), frequency of counseling parents regarding giving analgesics, frequency of parents asking questions about analgesia, opinions regarding who is responsible for provision of analgesia to child(ren) during immunization (physician, parent, or both), and whether children undergoing immunization should receive analgesics. Maternal use of analgesics (yes/no) was correlated with age, number of children, rating of pain during immunization, maternal report of excessive/unusual fear of needles in any child(ren), physician counseling practices, type of physician (pediatrician or family practice), and maternal opinions regarding whether children should get analgesics. Associations with P values ≤0.1 were entered into a backward linear regression (for physicians) and logistic regression (for mothers) to identify factors that predicted analgesic use. For these analyses, the criterion of a minimum of 10 respondents per variable in the model was met.29 Data were analyzed by using SPSS 12.0 (SPSS, Chicago, IL). A P value of ≤.05 was considered significant.
Of 462 pediatricians identified, questionnaires were mailed to 195 (42%). Of the remainder (n = 267), 191 were specialists, 37 did not administer immunizations, 22 could not be located, 8 relocated out of district, 6 retired, and 3 were on a leave of absence. Altogether, 140 (72%) responded (Table 1). Of the 257 mothers approached, 201 (78%) agreed to the study. For consenting versus nonconsenting mothers, median number of children (including newborn) was 2 in both groups (P = .26) and maternal age was 34 vs 36 years, respectively (P = .04). One participant was excluded after consenting because the only previous child was stillborn, thus, there were no previously immunized children (Table 1).
Pediatricians' reported frequency of analgesic use and type of analgesic used before injection and postinjection are displayed in Table 2. During injection, 58% reported that analgesics were rarely or never used in their practice. This is in contrast to only 11% who rarely or never used analgesics postinjection. During injection, the topical local anesthetics lidocaine-prilocaine and amethocaine were used at least sometimes (≥25% of the time) in 12% and 2%, of practices, respectively, whereas acetaminophen and ibuprofen were used in 81% and 46%, respectively. Postinjection, acetaminophen and ibuprofen were used in 89% and 56% of practices (Table 2). When asked to specify the reason(s) for use, 81 (58%) of 139 reported using analgesics during the injection phase for prevention of pain, 46 (33%) of 139 reported using them for prevention of fever, and 39 (28%) of 139 used it for both. For the postinjection phase, 119 (86%) of 139 reported using analgesics for pain and 126 (91%) of 139 for fever; 19 (14%) of 139 used it for either pain or fever, not both.
Mothers' reports of analgesic use in their children during immunization are displayed in Table 3. During injection, analgesics were used to reduce pain in 25% of immunizations. Postinjection, analgesics were used in 33% of immunizations. Mothers reported using acetaminophen (87%), ibuprofen (7%), or lidocaine-prilocaine (6%) to manage injection pain. Postinjection pain was managed with acetaminophen (86%) and ibuprofen (14%). Oral analgesics were used for either phase or both phases in 46% of immunizations.
Nonpharmacologic analgesic strategies (eg, distraction, holding child) were used by 97% of the pediatricians and 92% of the mothers.
Sixty-nine percent of pediatricians reported counseling parents about giving analgesics for the preinjection phase of immunization at least sometimes, compared with 98% who responded in a similar manner for the postinjection phase. When mothers were asked whether physicians had provided counseling about analgesia during the 2 phases of immunization, 42% and 66%, respectively, reported that they had. The reasons given by pediatricians and mothers for their analgesic practices are shown in Tables 4 and 5, respectively. Eleven percent of mothers reported that 1 of their children had an “unusual fear of needles.”
Linear regression analysis identified 2 variables that accounted for 45% of the variability in pediatricians' reported analgesic use during injection: years of experience (P = .002), and frequency of parental counseling about managing injection pain (P < .001). Years of experience was negatively correlated with analgesic use, whereas parental counseling was positively correlated with analgesic use. Postinjection, 3 variables accounting for 31% of the variability in analgesic use were identified: opinion that analgesia should be administered postinjection (P < .001), proactive counseling about postinjection pain management at a previous clinic visit or by telephone (P = .01), and frequency of parental counseling about managing postinjection pain (P = .02). For all variables, positive responses were correlated with increased analgesic use.
For mothers, analgesic use for the injection phase of immunization was predicted by whether the physician had provided previous counseling about managing injection pain (odds ratio [OR]: 14.6; 95% confidence interval [CI]: 5.9–36.4; P < .001). For the postinjection phase, significant predictors of analgesic use were physician counseling about managing postinjection pain (OR: 4.1; 95% CI: 1.7–9.6; P = .001), maternal positive opinion that postinjection pain in children should be managed (OR: 14.3; 95% CI: 1.8–116; P = .01), and number of children (where an increase of 1 child was associated with an odds ratio of 1.7 [95% CI: 1.1–2.7; P = .02) in analgesic use).
Immunization pain in childhood can be regarded as a universal public health issue. To our knowledge, this is the first study to examine analgesic practices aimed at reducing immunization pain. We found that topical local anesthetics were rarely used to manage injection pain, whereas oral analgesics were more frequently administered to manage injection and postinjection pain. These results are surprising, because scientific evidence consistently supports topical local anesthetics for injection pain but such evidence is equivocal for the use of oral analgesics postinjection.
Topical local anesthetics have been consistently shown to reduce injection pain (by ∼40%) during administration of various vaccines, including diphtheria-pertussis-tetanus,14,15 diphtheria-pertussis-tetanus and polio,19 diphtheria-tetanus-acellular pertussis-inactivated poliovirus–Haemophilus influenzae type b conjugate,18 hepatitis B,18 measles-mumps-rubella,16,17 and influenza virus vaccine.30 Moreover, they do not interfere with antibody responses.16–18,31 Nevertheless, this study demonstrated that they have not become widely adopted in clinical practice. Conversely, although studies do not support the use of acetaminophen for acute procedural pain,20,21 mothers that used it for the injection believed it decreased pain from the needle puncture. In addition, one third of the pediatricians reported using oral analgesics before injection to decrease pain during injection.
We found that oral analgesic use for the postinjection phase of immunization was more likely despite evidence that beneficial effects were only demonstrated for diphtheria-pertussis-tetanus vaccine.22,23,32 That vaccine included the whole-cell pertussis, which is associated with local and systemic reactions, including fevers and convulsions.33 It has since been replaced with a new acellular pertussis vaccine that causes significantly fewer adverse effects, and in a recent study of acetaminophen or ibuprofen versus placebo prophylaxis after combination diphtheria-tetanus toxoids-acellular pertussis vaccination, no clinically significant benefits were demonstrated for either drug.22 On the basis of these data, routine prophylactic use of oral analgesics cannot be recommended.
Planned painful procedures in children, such as immunization, continue to be performed without the provision of analgesia. Untreated procedural pain in childhood has been demonstrated to have significant adverse sequelae, including the development of hypersensitivity to future pain, preprocedural anxiety because of conditioning, and needle phobia.34 In fact, our study alone determined that an unusual fear of needles was present in ∼10% of the children, a rate consistent with previous literature estimates.35 Not only does immunization lead to significant distress for children, parents, and health care workers during future medical encounters, but it also leads parents and children to avoid seeking medical care in the future, even when children have reached adulthood.1,35 Parents report that suffering is the “worst thing” about medical treatment12 and maintain a willingness to pay for analgesics to reduce pain in their children.36–38 In light of these data, it is important to ensure that analgesics have been optimally adopted in clinical practice to manage childhood immunization pain.
The strengths of our survey are the inclusion of the major stake holders during immunization: parents of children undergoing immunizations and physicians performing immunizations. We used a comprehensive approach that separated the 2 phases of immunization (injection and postinjection) and determined analgesic practices for both. In addition, we targeted a population of physicians that administer immunizations to children and whose primary practice involves the care of children, which improves the likelihood that it represents widespread clinical practices. Moreover, we had a high response rate (72%). Although we did not survey family practitioners, regression analysis did not identify type of practice that children attended (family practice versus pediatrician) as a significant determinant of analgesic use for the mothers that participated in the study.
There were several limitations. Firstly, the self-reported practices of pediatricians and mothers were not validated. We tried to limit recall bias in mothers by limiting the questions to the youngest child(ren) and the most recent immunization. Given that both pediatricians and mothers reported infrequent local analgesic use during vaccine administration, it is unlikely that the results are erroneous. Moreover, that the mothers surveyed were not necessarily from the same physician practices further supports the validity of the results. For postinjection practices, pediatricians reported higher rates of oral analgesic use than mothers. It is likely that pediatricians are less accurate in estimating analgesic practices that occur after the clinic visit. For pediatricians, we did not have information on nonparticipants and do not know whether their practices differ. Also, the exact method by which various analgesic interventions were implemented (eg, administration techniques) and resulting effectiveness cannot be ascertained from this study. Although our study was limited to the GTA, we believe the results are generalizable to other urban settings across North America.
Our study suggests that physicians have concerns about the feasibility of using topical local anesthetics. Physicians identified parental factors (did not request analgesia) and drug factors (extra cost, time) as determinants of nonuse, whereas mothers reported that they were unfamiliar with these drugs and had not received medical advice about using them. Mothers reported they were willing to pay to decrease pain in their children, and it was demonstrated previously that parents can effectively apply topical local anesthetics at home before outpatient procedures, such as immunization, if given adequate instruction.14,39,40
Physician counseling was a significant predictor of injection and postinjection analgesic use, as reported by mothers and physicians. Considering that >80% of mothers had college or university-level education, and that information about managing immunization pain can be easily obtained from the Internet, it is surprising that mothers did not use this resource. Rather, they seemed to rely on their physicians to provide information to them. This may be in part because of their trust in their physicians, as well as time constraints.
Despite all the advances that have been made in modern medicine, pain minimization continues to be an unrealized improvement in pediatric care. Our data suggest that improvements in analgesic use can be made if physicians adopt the role of counseling parents about pain management and if parents are prepared to ask for it. We suggest that pain management instructions be included with immunization guides and that physicians include this information when counseling parents about immunizations. Information can also be included in pamphlets distributed to parents in the hospital or at the doctor's office after the delivery of a newborn infant, and/or on the child's immunization card. Moreover, vaccine manufacturers and governments should consider the pain caused by the vaccine as part of the scientific evaluation and determine the influence of concomitant analgesic administration on vaccine pain and antibody response.
This study demonstrated that pediatricians and mothers report infrequent use of topical local anesthetics in children undergoing immunization, whereas oral analgesics are used more frequently. Furthermore, physician counseling about management of immunization pain consistently predicted analgesic use, but many mothers were not counseled regarding pain management. Given that immunizations are planned procedures, that parents say they are willing to use analgesics to reduce pain in their children, and that parents can be counseled about them, current practices can be changed. Additional research is required to facilitate the required knowledge transfer.
This study was supported by a Pediatric Consultants grant, SickKids, the Canadian Pain Society, a Canadian Institutes of Health Research New Investigator Award (to Dr Taddio), and a RestraComp Graduate Studentship from the Research Institute, SickKids (to Ms Manley). The funding did not include any input into the design and conduct of the study; collection, management, analysis, or interpretation of data; or preparation, review, or approval of manuscript.
- Accepted January 29, 2007.
- Address correspondence to Anna Taddio, PhD, Department of Pharmacy, Hospital for Sick Children, 555 University Ave, Toronto, Ontario, Canada M5G 1X8. E-mail:
The authors have indicated they have no financial relationships relevant to this article to disclose.
Dr Taddio's current affiliation is Leslie Dan Faculty of Pharmacy, University of Toronto, and Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.
- ↵American Psychiatric Association. Specific phobia. In: Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Washington, DC: American Psychiatric Association; 2000:443–450
- Franck LS, Cox S, Allen A, Winter I. Parental concern and distress about infant pain. Arch Dis Child Fetal Neonatal Ed.2004;89 :F71– F75
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- ↵O'Brien L, Taddio A, Ipp M, Goldbach M, Koren G. Topical 4% amethocaine gel reduces the pain of subcutaneous measles-mumps-rubella vaccination. Pediatrics.2004;114(6) . Available at: www.pediatrics.org/cgi/content/full/114/6/e720
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