Health insurance companies Menzis and ONVZ say they have immediately removed a plug-in from their websites which fed information on visitor behaviour back to Facebook.

An investigation by broadcaster NOS found that 18 of the 40 health insurance company websites it studied contained the Facebook tracking pixel, with 11 placing it on pages showing medical information.

The social media platform uses the information provided by the tracking pixel to show people tailor-made adverts on their Facebook pages, if they are logged in at the time.

This means, for example, that Menzis can place an advert for its services on the Facebook page of someone who has visited their website and could be a potential client.

The tracker cannot trace confidential medical information but would tell Facebook if a person had visited a part of the health insurance company website covering sexually transmitted diseases, for example.

Privacy

Patient lobby group Patientenfederatie Nederland told NOS it wants the practice to stop. ‘Do yourself and your patients a favour and don’t pass on this information,’ spokesman Thom Meens told NOS.

Privacy lobby group Bits of Freedom said it is surprised by the health insurers. ‘We’ve had these sort of scandals before and I thought websites would have improved,’ director Hans de Zwart said. Deliberately placing pixels in websites is either ‘incompetence or shameless,’ he said.

The use of tracking pixels is not illegal if visitors to the website have agreed to the terms of use and cookie policy.

Many websites, such as webshops, use tracking pixels so they can offer visitors special deals or draw their attention to specific offers which fit their interests.