This abstract examines cortisol levels in infants and mothers during 2-, 6-, 12-, and 18-month vaccinations, and compares the effects of early exposure to maternal skin-to-skin contact versus 24% oral sucrose on later cortisol response. This abstract is a secondary analysis of completed longitudinal clinical trial data, where preterm infants were randomized to receive one of three interventions (a) skin-to-skin contact + placebo, b) skin-to-skin contact + 24% oral sucrose, c) 24% oral sucrose) during all painful procedures through their entire NICU stay. Infants and their families were invited to participate in a follow-up where they were followed during vaccination appointments at 2-, 6-, 12-, and 18-months.