This falls under workplace privacy as well as health privacy:
The Netherlands’ biggest private health and safety firm (arbodienst) has been passing confidential medical information to employers, television current affairs show Zembla will report on Friday evening.
Many Dutch firms rely on private companies to monitor health and safety in the workplace, follow up on sick workers and help get them back to work.
[…]
Zembla’s findings show confidential medical information has been given to employers and call centre staff have been used to question sick workers about why they are off work. By law, only company doctors can ask about the reason for sick leave.
Read more on DutchNews.nl