It’s still unclear exactly how long a person remains contagious for and it varies from one patient to the next.
It also sends a message to people that the worst is past so they can relax their behaviour and comes at a time when there are a series of other changes in prospect, such as removing confirmatory PCR tests, they say.
However, scientists say that there is a good chance that many people may still be infectious after five days and that the current isolation period of seven days is a much safer option.
“Speculation about reducing the self-isolation period for people who test positive for COVID-19 from seven days to five is not based on scientific evidence but on concerns about the impact of isolation on staff absences,” Professor Lawrence Young, a virologist at Warwick University, told i.
“A recent study from Japan has shown that peak infectiousness with omicron occurs at 3 to 6 days after diagnosis or symptom onset. Thus the current approach adopted in the UK of 7 days isolation with two consecutive negative lateral flow tests makes sense.
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“Reducing the self-isolation period to 5 days runs the risk of highly infectious people returning to work or school, particularly if lateral flow tests are not used.”
Professor Rowland Kao, of the University of Edinburgh, who sits on the Government’s SPI-M modelling committee, said: “Is this the time to cut isolation to five days? I would argue not. We are just coming off the Christmas period when transmission is naturally low, we are just moving to 7-day isolation for some, rather than 10, and just moving to remove confirmatory PCR tests.
“That’s a lot of changes going on at once, all of which may result in increased transmission and therefore greater stress on healthcare systems,” added Professor Rowland, who was speaking to i in a personal capacity. “For my part, epidemiologically speaking, I would wait at least until we had a good sense what the current round of changes will do, before making any further changes,” he said.
Simon Williams, of Swansea University, added: “There are question marks over how safe it is for somebody to come out of isolation after five days. I don’t think it’s following the science really.” Stephen Griffin, of Leeds University, said: “I don’t think this is a public health driven measure, I think this is obviously a need to get people back to work measure.
“I do worry that this is a decision that has been driven largely by policy rather than by public health…it’s not right.” Analysis
Scientific opinions also vary, in keeping with this uncertainty.Of the five scientists i spoke to yesterday afternoon, four were of the opinion that letting somebody back into the community after five days poses a greater risk of infection than leaving it for seven. There were also concerns that reducing the isolation period sends a strong signal that the worst is over and people can relax – which, in turn, could increase social contacts and further spread the virus.
There is still a lot of uncertainty about how long a person remains infectious for and just how infectious they are after five, six, seven, even ten days. Looked at solely in terms of case numbers – that is, in scientific terms – reducing isolation from seven days to five is likely to increase the spread of Omicron just as it may be starting to slow.
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