1. Department of Health Protection; National Institute for Health and Welfare; Kuopio Finland
2. Department of Environmental Science; University of Eastern Finland; Kuopio Finland
3. LMU Munich; University Children's Hospital; Munich Germany
4. University Children's Hospital Basel UKBB; University of Basel; Basel Switzerland
5. Institute for Laboratory Medicine and Pathobiochemistry, Molecular Diagnostics; Philipps-University of Marburg; Marburg Germany
6. Institute of Epidemiology and Medical Biometry; Ulm University; Ulm Germany
7. Department of Vaccinations and Immune Protection; National Institute of Health and Welfare; Helsinki Finland
8. Department of Public Health; University of Helsinki; Helsinki Finland