1. Department of Internal Medicine, Division of Infectious Diseases, Oulu University Hospital and University of Oulu, Oulu, Finland;
2. Lammi Health Centre, Hämeenlinna, Finland;
3. Nordlab Oulu, Oulu University Hospital, Oulu, Finland;
4. Respiratory Research Unit of Internal Medicine, Medical Research Centre Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland