aDepartment of Infectious Disease, Public Health Services
bCenter of Infection and Immunology Amsterdam (CINIMA), Academic Medical Center (University of Amserdam)
cDepartment of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center (University of Amsterdam), Amsterdam, the Netherlands.
Correspondence to Gerard Sonder, MD, PhD, Public Health Service Amsterdam, Amsterdam, Netherlands. Tel: +31 20 555 5003; fax: +31 20 555 5533; e-mail: email@example.com
Received 18 April, 2012
Accepted 25 April, 2012