- Correspondence to: Dr M Kuusi Department of Infectious Disease Epidemiology, National Public Health Institute, Mannerheimintie 166, 00300 Helsinki, Finland;
- Accepted August 13, 2003
- First published March 16, 2004.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.