Less than half of Covid-app notifications came up in source and contact tracing

The CoronaMelder app is a success in that it reaches a wider proportion of the population than health service GGD's source and contact tracing, according to researchers at Erasmus University. About 58 percent of people who got an app notification that they were in close contact with someone who tested positive for Covid-19 were never contacted by the GGD in source and contact tracing, the researchers found, RTL Nieuws reports.

"Our research shows that 58 percent only received a message via the app. Without CoronaMelder, this group would not have come into the picture, or not on time," professor Wolfgang Ebbers said. 

The CoronaMelder app has been downloaded by nearly 4.7 million people in the Netherlands. The app uses Bluetooth to keep track of who you get close to and for how long, using anonymous codes. If someone tests positive for Covid-19 and reports it on the app, the app will notify all other app users who spent 15 minutes or more in their vicinity at a distance closer than 1.5 meters. 

The researchers found that a significant number of people do not adhere to the advice provided by the app after Covid-19 exposure. Less than half of people who received a notification that they were exposed actually quarantine at home. And only half make a test appointment on the same day that they received the notification.

The government needs to communicate more about the app in order to make sure that more people adhere to the advice to stay home and get tested, the researchers said.

According to the researchers, young people more often received Covid-19 warnings through the app than older people. "A possible explanation for this is that young people are more socially mobile than older people," the researchers said.