Pain reativity in the vaccination of infants between two and five months of age, who received sucrose

Vaccination is an effective strategy to prevent disease and reduce morbidity and mortality. However, this exposes patients, specially, children to painful procedures, which can lead to immediate and long-term consequences related to the pain response. To minimize these consequences, several interventions have been investigated to relieve pain resulting from vaccination, among which sucrose. Despite the proven effectiveness of sucrose for pain relief in single procedures and vaccination, it is known that several factors may interfere with reactivity to pain, and little is known about the repeated use of sucrose in the equally repeated vaccines in the first months of life. Thus, with the aim of examining the factors that interfere with reactivity to pain in the vaccination of infants between two and five months of age who received sucrose, and to evaluate and compare reactivity to pain in the vaccination of infants at this age, we developed an observational cross-sectional study which included 272 infants who attended the study\'s vaccine room to receive the vaccines proposed in the vaccination schedule for the State of São Paulo, from October 2014 to May 2015, and whose parents or guardians agreed to participate in the study through signed Free and Informed Consent Form. The following were excluded: infants who did not live in the city of Ribeirão Preto; those with suspected or intolerance to fructose; with congenital nervous system disease; with malformation or severe neurological impairment; those who did not follow the regular schedule of vaccination or needed special vaccines. Data were collected on the proportion of facial mimetic, heart rate and crying in the basal (90s), preinjection (120s), injection and post-injection (180s) and exposure factors related to birth and mother. Behavioral data were obtained through systematic observation, with sequential analysis according to each second. The database was structured in Excel spreadsheet and exported to SPSS software. For the analyzes, the main outcome was the proportion of facial mimetics in the injection phase. In the unadjusted linear regression model, we identified that there was influence on the variables of exposure: current weight, number of previous pregnancies, facial mimetic in the basal phase, and heart rate (HR) in baseline, considering a p<0.20. For the multiple regression model, only the influence of facial mimicry on the basal phase (p=0.001) was identified. As risk factors, student t tests for the numerical variables of normal distribution and Mann-Whitney for categorical variables or numerical variables of non-normal distribution, we identified risk for the variables; (p=0.048) and HR (p=0.030), facial mimetic (p=0.000) and crying (p=0.029). For the analysis of repeated measures (ANOVA-RM) we identified that the proportion of facial mimetics was significantly higher in the administration of the three consecutive vaccines (pneumo + VIP + penta), compared to the single (meningococcal vaccine), only in the post-injection phase (p<0.001). For repeated participation two or three times of the same infant (n=460), we identified that the proportion of facial mimicry differed statistically between the phases in the four groups of different ages (p>0.05), presenting higher values in the injection phase. We conclude that despite the effectiveness of sucrose for pain relief, risk factors that interfere with pain reactivity, mainly differences in facial mimicry post-injection when multiple and consecutive vaccines (10-valent pneumococcal, injectable polio, pentavalent) versus single vaccine (meningococcal C) (AU)