Disease experts have questioned the necessity of the United Kingdom's COVID-19 contact tracing apparatus and isolation rules, which have led to major worker shortages and disrupted supply chains.

In the UK, the national healthcare app is designed to contact or "ping "individuals who have come within 2 meters of someone who later tests positive for COVID-19. Daily cases of the novel coronavirus have shot up during the past month in the UK, regularly breaching 40,000, sending the contract tracing system into overdrive, with 500,000 people pinged in the first week of July, the most recent period for which National Health Service, or NHS, data is available.

Government guidance stipulates that pinged people should isolate for 10 days, resulting in many industries facing employee and stock shortages. Supermarket chain Iceland said it has closed a number of stores after 1,000 employees, or 4 percent of its workforce, were told to isolate. The chain is drafting in 2,000 temporary employees to make up for the disruption.

Tim Spector, a professor of genetic epidemiology at King's College London and principal investigator of the ZOE COVID-19 symptom study, questioned the need for the system, which requires people to self-isolate even if they are fully vaccinated and test negative for the virus.

"It doesn't seem to be appropriate at the moment, it seems to be overkill," Spector told Sky News on Thursday. "I think employers have got to just use common sense… I think employers should tell their staff if they feel unwell, they have cold-like symptoms, then they stay away but I don't think the app saying that someone might have passed them by in a supermarket is actually that useful anymore in the current state of the pandemic."

Jonathan Stoye, a virologist at the Francis Crick Institute, questioned if self-isolation should be necessary for pinged people who are double vaccinated and who test negative.

"It would not seem unreasonable for it to be considered whether the self-isolation instruction needs to apply to those people," Stoye said.

But other experts are convinced of the importance of the current system. In the UK, daily confirmed cases of the virus are the most plentiful they have been since January, so a large number of pings are to be expected, said Jon Crowcroft, a professor of communications systems in the computer science department at the University of Cambridge.

"There's nothing much wrong with the app, just people aren't socially distancing enough," Crowcroft said.

He added that the number of notifications that occurred in the first week of July is "in line with what you would expect", given that roughly 250,000 people tested positive during that period.

"If each person testing positive met about four people a day, and you had a roughly 50/50 chance they and the other person were running the app, which is approximately right, then you'd expect to see about 500,000 people getting notified," Crowcroft said.

Simon Clarke, an associate professor in cellular microbiology at the University of Reading, said that "self-isolation is one of the most effective tools we have to prevent spread".