People could be asked to ‘self-quarantine’ after spending time with relatives at Christmas

The papers released by Sage suggest “an extensive education campaign” about how to minimise dangers in places with an increased risk of infection transmission such as large family gatherings, pubs and parties. 

Other Sage papers suggest there is a growing body of evidence to suggest that quarantine periods could be reduced and that young people should be given free mobile phone data and financial help to improve compliance with self-isolation.

The Government is understood to be considering halving the quarantine period amid concern about low levels of compliance with the current 14-day rule. 

In a paper on transmission routes of Covid, it notes: “The greatest viral load, and thus infectiousness, is observed during the first week of symptoms (especially day 0-5), declining after that.” 

The paper summarises a series of studies, including one of 100 confirmed cases of Covid-19 and 2,761 close contacts which found that secondary infection rates were higher among those contacts whose initial exposure to the index case happened within five days. No secondary cases were identified five days after the symptom onset.

A separate study quoted found that on average, exposure occurred within three days of symptom onset. Researchers said that, although traces of Covid’s genetic code could be detected in the upper respiratory tract for 17 days on average after symptom onset, this did not necessarily equate to infectiousness. 

Eight studies using testing which looked for current antigens found that cases were rarely positive beyond nine days of illness, indicating a likely infectious period of around nine days from symptom onset. 

The paper also said evidence continues to suggest that “super-spreading” events may play a very important role in the epidemic, with fewer than 20 percent of infections leading to approximately 80 percent of secondary cases.