(Bloomberg) -- Politicians and scientists in the U.K. are concerned that people are deleting the official Covid-19 mobile phone app, or at least switching off its tracing function, to avoid having to self-isolate.

Just under 620,000 people in England and Wales were “pinged” by the National Health Service Covid-19 app and told to isolate in the past week -- a record, and up from around 530,000 the week before, official figures show.

Yet the recent rate of growth in app alerts has been slower than the increase in Covid-19 infections. That’s stirred warnings that amid the growing furor about a “pingdemic” and its impact on key industries, more people are simply disabling a key part of the app that the government and health experts say is critical to halting the spread of the disease.

The fear is that public trust in the test, trace and isolate program as a whole is eroding, just as virtually all pandemic rules were lifted in England this month.

“It isn’t rocket science: if you’re asking people to do something that’s difficult for them, guess what -- they’re not going to do it,” said Henry Potts, a professor at University College London who specializes in health data. “Isolating is difficult, it’s inconvenient -- for some people it’s very difficult.”

Potts said surveys show an increase in the number of app deletions in the last few months, and that suggestions ministers were considering tweaking the app to make it less sensitive had been “unhelpful.” They drew “attention from the fact that the reason you’re being pinged is that there’s lots of cases,” he said.

An opinion poll by Savanta ComRes released this month found that a third of 18 to 34 year-olds in the U.K. have deleted the app, having previously downloaded it. Jenny Harries, head of the U.K. Health Security Agency, told members of Parliament that she was “aware that people are choosing not to use the app.”

The app uses Bluetooth technology to anonymously detect whether users have been within two meters of someone who’s subsequently tested positive for Covid-19 for 15 minutes or more. There’s no legal duty to self-isolate when someone gets an alert, but it’s strongly encouraged by the government.

“The reason that so many people are receiving notifications is simple. We have a highly transmissible virus that is being allowed to spread throughout the country with the bare minimum of mitigation,” said Stephen Griffin, associate professor in the University of Leeds School of Medicine.

Reopening

Daily cases in the U.K. as measured by specimen date reached more than 60,000 last week but have receded a bit. Cases fell for a third day on Friday, pulling the seven-day rolling average down to 44,249 from a recent peak of 47,696. Scientists, though, caution that the effects of reopening the economy haven’t yet filtered through into the data.

As food and logistics companies warn of critical staff shortages, ministers are allowing limited numbers of key workers to avoid the 10-day self-isolation that’s supposed to follow a “ping,” to ensure services can keep running. The government is also planning to exempt anyone who’s fully vaccinated from Aug. 16.

That change should happen immediately to avoid “large numbers of people” deleting the app and even avoid getting tested, senior Conservative MP Mark Harper told Parliament on Thursday. “People will simply stop listening and that’s very dangerous for public health,” he said.

The Department of Health and Social Care said the app had been downloaded over 26 million times, but declined to comment on how many people had since deleted it or switched off the contact tracing function.

The app prevented an estimated 600,000 Covid-19 cases and 8,000 deaths between September and December 2020, a spokesperson for the department said.

“The whole point about self-isolation is that we are protecting wider society and I think that people should be following the rules,” Business Secretary Kwasi Kwarteng told Sky News on Thursday, calling it a “real shame” if people are deleting the app.

©2021 Bloomberg L.P.