While a contact-tracing app is being pitched as one possible solution to safely ease lockdown measures, there remain some concerns and limitations that experts behind the technology are exploring.

These range from data privacy, to fears of making the digital divide worse between those with and without a smartphone, as well as questions about what it will mean for children.

– Will my data be safe?

Privacy has been one of the biggest concerns about using the app.

NHSX says people won’t be identifiable because an anonymised ID is created on each smartphone which can’t be traced back to the owner.

The only details people will be asked to provide is the first part of their postcode, to help inform epidemiologist’s research, identifying possible hotspots for the virus for example.

“As we have developed the app, we’ve put privacy right at the heart of it and the way it works,” said Matthew Gould, chief executive of NHSX.

“The app is designed so that you don’t have to give it your personal details to use it… it doesn’t know who you are, it doesn’t know who you’ve been near, it doesn’t know where you’ve been.”

– What about those without a smartphone?

It is important to remember that not everyone has a smartphone and there are also those who may not be tech-savvy to use one.

“We’re very conscious not everyone has mobile phones, not everyone can or want to use the app, and we need to make sure that we don’t accidentally exacerbate the digital divide here,” Mr Gould continued.

“So we’re working closely with departments across government, particularly in the Department for Culture, Media and Sport (DCMS) to make sure we’ve got plans in place to mitigate the risk of digital exclusion, and that’s why the contact tracing is so important because it makes sure that there is an option for those that don’t have the app, that they can still tie into the programme.”

– Where do children stand in all of this?

How children play into the contact-tracing app’s objective has not been determined, officials have admitted.

“It’s an unresolved issue about how the app will or will not apply to children, but just to reinforce the messages from previously, the app is part of an overall contact-tracing system and it absolutely never will be the case that children are excluded from contact tracing, or from testing if they have compatible symptoms,” said Professor Jonathan Van-Tam, deputy chief medical officer for England.

“But it is true scientifically that we remain somewhat uncertain about the role of children in transmitting Covid-19, but I think most of us on the call would agree that the scientific evidence for that is probably increasing rather than decreasing over time.”

– Is there a risk of false positives?

Yes, NHSX has said it is theoretically possible for the app to flag false positives, such as neighbours that appear close together to the app, but are in fact either side of a thin wall in a block of flats.

Mr Gould said NHSX would continue to work to improve the app to avoid false positives, but the developers were confident from their testing so far that it would not be an issue. 

“We’re very alive to the issue of false positives, because if people are pinged by the app and it turns out not to be case that they were at risk obviously that has an effect on confidence,” he said.

“So, we are really keen to try to make sure the app is as accurate at assessments as possible.

“Yes, it is a theoretic possibility, but we think it is relatively unlikely, we’ve been testing it. 

“But again it’s something that we will try and get better at over time so we can distinguish what is likely to be a genuine contact event from what’s not and what’s likely to be risky compared to what’s going to be less risky. 

He added that NHSX would continue to “hone” the app through testing, and it hoped to “over time be able to reduce the level of false positives – clearly not to zero – but we’ll definitely be able to make the effect of the app more and more accurate”.