Note: Funding Information: Funding information This work is in part supported by a CSO/NRS Scottish Senior Clinical Fellowship award (SCAF/16/03) and The Netherlands Organisation for Scientific research (NWO-VIDI grant no. 91715359) Funding Information: We thank M. Kristensen and M. Reyman for their unrelenting support. Part of this train of thought was presented by DB at the Congress of the World Society for Pediatric Infectious Diseases in Shenzhen, China (December 2?5, 2017).