Government figures show a 26 per cent drop in the number of 'pings' being sent to Isle of Wight users of the NHS Covid app.
A total of 1,356 Islanders were alerted by the technology in the week to July 28.
That is 420 fewer than the previous week when 1,776 people were 'pinged', according to NHS England figures.
Alerts were sent to people who have been in ‘close contact’ with someone who has tested positive for coronavirus.
During that period, just 84 Islanders used the app to report symptoms of the virus.
In the week to July 28, 8,811 checked-in to venues using the NHS QR codes - a fall of 61 per cent compared with the previous seven days.
Meanwhile, in those seven days, 838 people were contacted by Government test and trace teams.
Department for Health data also shows, in that week, 249 people were transferred to the contact tracing system.
A fall in app pings appears to be a national trend. Across England and Wales just under 396,000 people were told to self-isolate in the same period - down 43 percent on the previous week.
It comes ahead of changes which will ensure the app sends fewer alerts. The Department for Health and Social Care said it would change the "logic" behind the mechanism.
Instead of looking at contacts five days before someone tests positive, the app will now check contacts two days before.