Denmark, Slovakia, Iceland added to England's travel quarantine list

"Data shows we need to remove Denmark, Slovakia, Iceland, and Curacao from the Travel Corridor list," Transport Secretary Grant Shapps said on Twitter on Thursday, Xinhua news agency reported.

Travellers arriving in England from those countries after 4 a.m. BST (0300 GMT) on Saturday must self-isolate for 14 days, he added.

The quarantine decisions made by the British government are based on such factors as whether a country's weekly infection rate is above 20 cases per 100,000 people.

Meanwhile, another 6,634 people have tested positive for coronavirus, the highest daily increase since COVID-19 broke out in Britain, Public Health England (PHE) said Thursday.

A total of 40 new coronavirus deaths have also been recorded, the PHE said on Twitter.

Also on Thursday, more than one million people have downloaded the British government's long-anticipated contact-tracing app for England and Wales within its first day of launch.

The official NHS COVID-19 app instructs users to quarantine for 14 days if it detects they were nearby someone who has the virus.

"Everybody who downloads the app will be helping to protect themselves, helping to protect their loved ones, helping to protect their community because the more people who download it, the more effective it will be," British Health Secretary Matt Hancock told the BBC.

The launch of the app came at a time when countries such as Britain, China, Russia and the United States are racing against time to develop coronavirus vaccines.

The British government's Chief Scientific Adviser Patrick Vallance said Monday that it is possible that some vaccine could be available in small amounts later this year, but it is more likely that a vaccine will be available early next year, although that is not guaranteed.