Contact tracing apps could be used to control the COVID-19 outbreak. Most of them work by automatically registering another smartphone when it is close by for a set period of time. If the user then tests positive for COVID-19 in the future, the contact tracing app notifies these contacts. Concerns have been raised about misuse of personal data. Initial data suggests there has been slow uptake of this new technology by users, and it's unclear if contact tracing apps have had or will affect the pandemic. Northern Ireland, Scotland, and now England and Wales have recently launched contact tracing apps.