LONDON (Reuters) – The COVID-19 smartphone app being developed by Britain will be able to give serious insights into the virus by virtue of using centralised matching, despite its offering less privacy than rival apps, the head of the programme said.
Countries are rushing to develop apps which, along with a wider testing and tracking programme, are seen as key to easing social distancing rules that have all but shut global economies.
Britain has opted for a centralised model, whereby a list of contacts made via bluetooth signals are stored on a users’ device as anonymous tokens.
If the user has symptoms or tests positive for COVID-19, the list of contacts can be submitted to the app, which analyses the data and notifies devices matching the tokens it deems at risk, for example because of the time the devices were in proximity.
Rival systems, including one proposed by Apple and Google, match the lists of tokens on the devices themselves, removing the risk of sending data to a centralised server, even if it is anonymised.
“If privacy was the only thing we were optimising for here, then it may well be that a decentralised approach should be the default choice,” Matthew Gould, chief executive of the National Health Service’s technology group NHSX, told a parliamentary committee on Monday.
But privacy had to be balanced against public health, he said.
“It was our view that a centralised approach gave us the potential … to collect some very important data that gives serious insight into the virus that will help us,” he said.
The insights a centralised approach could bring include data on which symptoms develop into COVID-19, which contacts are more risky, and the difference, for example, between a contact three days ago and one yesterday, he said.
He added that Britain was talking to international partners and was also working “phenomenally closely” with Apple and Google.
“We are not in competition, we are all trying to get this right,” he told the committee.
Reporting by Paul Sandle; editing by Stephen Addison