LONDON - The compulsory self-isolation period for people with symptoms of Covid-19 has been extended from one week to 10 days with immediate effect, the UK’s chief medical officers have announced.

Until now those with symptoms of the virus – a high temperature, a continuous cough, or loss of taste or smell – have been told to quarantine themselves at home for seven days.

Under the new guidance, that period will increase by three days following a fresh look at the latest scientific evidence.

HuffPost UK understands that there has been no specific change in evidence that triggered the change, but the medical officers decided to act now while prevalence was low and want to prepare the country for a second spike in the autumn or winter.

All four medical officers in England, Northern Ireland, Scotland and Wales considered that they had to be “ultra cautious” given the “low but tangible possibility” that patients are infectious between seven and nine days after the onset of the illness.

Those without symptoms but who test positive for the virus should also self-isolate themselves for 10 days.

The change in advice brings the UK into line with the World Health Organisation’s global recommendation on home quarantine, which has already been adopted by many countries for months.

The guidance from the NHS states that people must self-isolate for 14 days if they live with, or are in a bubble with, someone that has symptoms or has tested positive or they are contacted by NHS Test and Trace.

That two-week period will remain unchanged.

In a joint statement, the medical officers said: “Evidence, although still limited, has strengthened and shows that people with COVID-19 who are mildly ill and are recovering have a low but real possibility of infectiousness between 7 and 9 days after illness onset.

“We have considered how best to target interventions to reduce risk to the general population and consider that at this point in the epidemic, with widespread and rapid testing available and considering the relaxation of other measures, it is now the correct balance of risk to extend the self-isolation period from 7 to 10 days for those in the community who have symptoms or a positive test result.

“This will help provide additional protection to others in the community. This is particularly important to protect those who have been shielding and in advance of the autumn and winter when we may see increased community transmission.”

The statement was agreed by Chief Medical Officer for England, Professor Chris Whitty and his counterparts Dr Michael McBride in Northern Ireland, Dr Gregor Smith in Scotland and Dr Frank Atherton in Wales.

The advice change relates to cases in the community rather than in hospital or care homes, where patients may have suppressed immunity.