The Effect of Breastfeeding Versus Sensorial Saturation on Infants' Behavioral Responses of Pain following Pentavalent Vaccination on 4 and 6 Month Old Infants: A Randomized Controlled Clinical Trial Study.

Single-center study in Yasuj, Iran, using convenience sampling, so results may not apply to other settings or infants with different feeding or health backgrounds. Only the data analyst was reported as blind; the researcher who measured crying and scored pain was not described as blind, which may affect subjective outcomes. The sensorial saturation intervention was a bundle of positioning with flexed limbs and limited movement of the vaccinated organ, dextrose, lavender, eye contact, gentle talking, and face and back massage, so the study cannot identify which component caused the pain reduction. Breastfeeding was stopped before the injection rather than continued during vaccination, so the comparison may not match practices where infants breastfeed during the injection. Outcomes were short-term behavioral pain scores and crying duration only; the study did not assess physiological pain, longer-term pain responses, or vaccination acceptance. Nine infants did not continue at 6 months, so 171 of 180 enrolled infants were analyzed at the second time point. The authors note that vaccine pain is transient and differs from acute or chronic pain, and that the two-month interval prevented within-group comparisons.

The study was supported by the Vice Chancellor for Research of Yasuj University of Medical Sciences with grant number 23.2.808, and the authors declared no conflicts of interest.

Do not conclude that positioning, dextrose, lavender, eye contact, gentle talking, or face and back massage each reduced infant pain. They were delivered together as sensorial saturation, and the study did not test them separately.