Thousands more workers in England will not have to enter quarantine if they are a close contact of a Covid-19 case, the government has said.
This comes amid increasing concern over disruption caused by the “pingdemic”.
Train drivers, lorry drivers, police officers and border officials are now able to join a daily testing initiative, meaning they can continue working if they receive an alert – known as a “ping”.
The expanded scheme comes a day after the government made supermarket depot and food factory workers exempt from self-isolation rules to avoid food shortages.
Several sectors have complained of staff shortages in recent days.
Supermarkets have warned shoppers may find some products are in low supply, as record numbers of staff are told to self-isolate.
About 608,000 contact tracing alerts were sent from the UK's National Health Service Covid-19 app in the week to 15 July – a record high.
On top of 500 testing sites set up at food factories, a further 100 will be established for the transport and freight industry, allowing lorry and train drivers to keep working if they test negative.
There will also be 100 testing sites for emergency services and border officials, including frontline police officers and firefighters.
“Daily contact testing of workers in these critical sectors will help to minimise any disruption caused by rising cases in the coming weeks, while ensuring staff are not put at risk," Health Secretary Sajid Javid said.
Self-isolation rules for fully vaccinated people are due to end in England on August 16.
The government has been reluctant to bring this date forward to avoid a further rise to the infection rate.
“We have to keep a very close eye on hospitalisations,” Environment Secretary George Eustice said on Friday.
But London Mayor Sadiq Khan said the “crucial summer months” for many businesses were being put in jeopardy by staff shortages.
“Many hospitality businesses, such as pubs and restaurants, are already struggling with staff shortages,” he said.
“These shortages have been exacerbated, in some cases leading to temporary closure, by large numbers of employees being simultaneously advised to isolate by the NHS Covid app.”
He called on the government to replace self-isolation with daily testing for fully vaccinated workers.
“It is vital that both employers and employees retain faith in the NHS Covid-19 app to help prevent the spread of the virus and further damage to London’s economy, and that is why we hope you will give urgent consideration to our request,” he said, writing on behalf of the London Covid Business Forum.
Meanwhile, scientists have expressed optimism that daily Covid-19 figures from the last few days could be an “early sign” that the infection rate may be falling.
Prof Adam Kucharski, an epidemiologist from the London School of Hygiene and Tropical Medicine, cautioned that it may be a “false peak”.
“Of course that change on Monday, that big reopening, has not yet shown up in the data,” he told BBC’s Radio 4 on Saturday.
“So I think the next week or two is going to be crucial to know if this is genuinely a slowdown of a potential peak, or if we've got more transmission to come.”
A further 36,389 people tested positive with another 64 deaths recorded on Friday.
Prof Kucharski predicted that alerts from the Covid app would remain high, saying “there’s an awful lot of Covid out there”.
“If you go out and have contacts, it's very likely you'll be near someone who has the virus,” he said.
