Using feeding to reduce pain during vaccination of formula-fed infants: a randomised controlled trial.

OBJECTIVES: To assess the effectiveness and potential side effects of formula feeding to reduce pain during vaccination among infants.

STUDY DESIGN: In the setting of well-baby clinics we recruited a community-based sample of full-term born infants who were already formula fed by the choice of the parents (n=48, aged 4-10 weeks) and received their first DTaP-IPV-HepB-Hib and pneumococcal vaccinations and randomised them into two groups. To evaluate pain experienced during vaccination we compared infants who drank formula feeding before, during and after vaccination with infants who did not. Outcomes were observed cry duration and pain scores measured by means of the Neonatal Infant Pain Scale (NIPS) and the Face, Legs, Activity, Cry and Consolability (FLACC) scale. Side effects of drinking during vaccination were recorded. We performed intention-to-treat analyses using regression models, crude and adjusted for sex and age of the infant.

RESULTS: Pain at the moment of the second injection did not differ between groups. Drinking infants cried 33.5 s shorter (-56.6; -10.3). In the first minute after injection drinking infants experienced a faster pain reduction on the NIPSΔt : regression coefficient 3.86 (95% CI 2.70 to 5.02) and FLACCΔt : 4.42 (95% CI 2.85 to 5.99).

CONCLUSIONS: In line with findings of previous studies regarding breast feeding, formula feeding reduced vaccination pain in the recovery phase in full-term born infants receiving their first vaccinations between ages 4 and 10 weeks with no adverse effects. Professionals should discuss this non-costly and feasible pain-reducing intervention with parents of infants who receive vaccinations.

TRIAL REGISTRATION NUMBER: IRCTN 31383, post-results.