The Effect of Rotavirus Vaccine on Socioeconomic Differentials of Paediatric Care Due to Gastroenteritis in Swedish Infants.

Background: Previous Swedish studies have shown a social gradient on paediatric care for viral gastroenteritis. Aim: To study the effect of a free rotavirus vaccine programme on hospital care for viral gastroenteritis. Method: A register-based national cohort study of paediatric in- and outpatient care for viral gastroenteritis in children <2 years old in two Swedish counties in 2014⁻2017, with the rest of the country as comparison. Adjusted hazard ratios were estimated by the differences-in-differences (DiD) estimator in Cox regression in the entire cohort and by social indicators. Results: Reductions of 37% and 24% for inpatient care, and 11 % and 21% for outpatient care for viral gastroenteritis were found in the Stockholm and Jönköping counties, respectively, after adjusting for time trends and social indicators. For inpatient care, the change was similar over social groups in both counties. In the larger county of Stockholm, smaller reductions in outpatient care were detected for children in socially disadvantaged families. Conclusions: A free rotavirus vaccination programme moderately reduced paediatric care for viral gastroenteritis. There were indications of an increase in socioeconomic differences in paediatric outpatient care for viral gastroenteritis, but further studies are needed to confirm this result in a broader health care perspective.