The Dutch government’s coronavirus warning app, which alerts users if they have spent 15 minutes close to someone who tests positive for the virus, is sending out some 10,000 warnings a day, broadcaster NOS said on Thursday.

However, the health ministry’s chief information officer Ron Roozendaal, who is in charge of the app, told the broadcaster than in some cases warnings are being sent when users were further away than the official 1.5 metres distance.

‘In most cases, the app gets the distance right, but in a small proportion of the cases, the person will be at a greater distance,’ he said. The app has been downloaded 3.66 million times.

In earlier trials of the app, 70% of reports involve being at least 1.5 metres from someone with coronavirus and 20% were between 1.5 metres and three metres. But 80 people who took part in trials got a positive report even though they were up to 10 metres away.

Official do not know in reality how many people are being warned about potential infections when they were further than 1.5 metres from an infected person because the system does not keep records. The 10,000 warnings figure is also an estimate.

‘But some 1,400 to 1,500 people who test positive are using the app on a daily basis, and we estimate they have had five to 15 contacts,’ Roozendaal told the broadcaster.

Despite the variations, the official advice remains that people who have had a warning should go into quarantine for 10 days, and have a test if they start showing symptoms.