Here in the Netherlands we don't have a fixed amount of sick days, it is unlimited (well, up to 2 years). Granted, you get less payment after a few sick days. Payment and days vary per sector. Like only 70% payment if you are still sick after 2 days.
So, if you have a nasty flue and need to stay home for 2 weeks, you can do that. Your employer could send an agency over to check if you are really ill.