1. Division of Paediatric Infectious Diseases, Department for Women's and Children's Health University of Padua Padua Italy
2. Penta–Child Health Research Padua Italy
3. Department of Statistics and Quantitative Methods, Division of Biostatistics, Epidemiology and Public Health, Laboratory of Healthcare Research and Pharmacoepidemiology University of Milano‐Bicocca Milan Italy
4. Società Servizi Telematici‐Pedianet Padua Italy
5. PharmacoEpidemiology and Drug Safety Research Group, Department of Pharmacy, and PharmaTox Strategic Research Initiative University of Oslo Oslo Norway
6. MRC Clinical Trials Unit at University College London London UK