Hospitalisations due to respiratory syncytial virus infection in children with Down syndrome before and after palivizumab recommendation in Japan

Abstract

Aim Down syndrome has been considered an independent risk factor for respiratory syncytial virus (RSV) infection. Palivizumab, an anti‐RSV humanised monoclonal antibody, was currently approved for all children with Down syndrome in Japan. To investigate the change in RSV‐associated hospitalisation (RSVH) rates before and after the universal approval of palivizumab in Japan in 2013, we conducted a nationwide retrospective survey. Methods We conducted a nationwide, retrospective, questionnaire survey across paediatric institutions in Japan. The recruited children with Down syndrome were divided into two groups: those born April 2010 to March 2013 (2010‐2012 cohort) and those born April 2013 to March 2016 (2013‐2015 cohort). Results Of the 664 institutions, 321 (48.3%) replied, and a total of 3,929 children with Down syndrome was registered. The percentage of children who received palivizumab increased from 49.2% to 82.2%. The cumulative RSVH rate showed a decreased trend in the 2013‐2015 cohort (OR, 0.83; 95%CI, 0.63‐1.10), while the rate of these children (without CHD and born at a gestational age ≥36 weeks) was significantly decreased in the 2013‐2015 cohort (OR, 0.56; 95%CI, 0.34‐0.92). Conclusion The cumulative RSVH rate tended to be decreased after approval for all children with Down syndrome although the result was not significant.