Health officials have clarified that the recommended Covid self-isolation period in the US is shorter than in the UK at a time when the prime minister is considering reducing it to five days.
The UK Health Security Agency (UKHSA) previously said the isolation period was in effect the same in both countries. It said the recommended minimum of six full days in the UK was counted from the onset of symptoms, while in the US, the five-day isolation began from the day of a positive test, which could be several days after the first symptoms.
However, the UKHSA has updated its blogpost, which now states: “In the UK our advice is to self-isolate for at least six full days from the point at which you have symptoms or get a positive test, whichever is first.”
It continued: “In the United States, the advice is to isolate for at least five full days from the same point.”
The blogpost concludes: “We believe that allowing people to leave self-isolation after two negative lateral flow tests on days six and seven is the optimal approach at present. This supports people who are unlikely to be infectious to go back to work and resume other activities, but continues to protect the wider population from infection.
The UKHSA said it made the correction after the US CDC health protection agency clarified that its isolation period started when symptoms first appeared.
The CDC cut the recommended isolation period there to five days in December. Boris Johnson has been facing calls from MPs and business bosses to follow suit in the UK in order to help ease staff absences across the economy and public services.
On Monday, the prime minister said he would “act according to the science” on potentially reducing the time period to five days.
The period has already been cut from 10 days to seven, as long as the person in isolation has negative lateral flow test results, and Johnson’s official spokesman said “if it is possible to go further then we will do so”.
The UKHSA is leading work on the issue along with the government’s Covid taskforce based in the Cabinet Office.
On the change to its blogpost, a UKHSA spokesperson said: “We updated our blog following clarification from the CDC on their isolation guidance on 4 January.”
On Sunday, the education secretary, Nadhim Zahawi, said it would be “helpful” to cut the isolation period to five days because of the pressures on the UK’s workforce.