Omicron – latest research and expert views as PCR test rules change

Experts from Imperial are working to improve understanding of the Omicron variant and its impact on health systems in the UK and around the world.

As case numbers rose to record numbers over the Christmas period and testing rules changed, here’s what Imperial experts had to say about the UK’s epidemic.

PCR tests for positive lateral flow scrapped

On Wednesday (5^th January), the government announced that confirmatory PCR tests for people who receive a positive lateral flow test will be temporarily scrapped, meaning those who test positive on a lateral flow device will be required to self-isolate immediately.

The change comes after the UK’s testing system was reported to have been overwhelmed over the Christmas period following unprecedented demand caused by high infection rates.

Speaking to the i newspaper, Professor Azeem Majeed, Head of Imperial’s Department of Primary Care & Public Health, said the move was a “positive step” in the right direction.

He said: “If you’re positive on lateral flow tests (LFTs) that’s almost certainly diagnostic of a COVID-19 infection in the current situation we’re in, as infection rates are so high.

“By not then having to take a PCR test, it takes pressure off the PCR testing system.”

Professor Majeed also wrote in the Guardian on 30^th December that there was a need to prioritise testing for healthcare staff and other key workers in times when the supply of tests is low.

London cases ‘possibly plateauing’

There are reasons to be “cautiously optimistic” that COVID-19 infection rates in London may be plateauing and cases should start to fall across the country in the next one to three weeks.

Professor Neil Ferguson, Director of Imperial’s MRC Centre for Global Infectious Disease Analysis and Jameel Institute, told BBC Radio 4’s Today programme on Tuesday that the Omicron wave would not be able to sustain record-high numbers forever so cases should begin to fall soon.

He said: “I think I'm cautiously optimistic that infection rates in London in that key 18 to 50 age group - which has been driving the Omicron epidemic - may possibly have plateaued.

“It's too early to say whether they're going down yet, but I think... this epidemic has spread so quickly in that group it hasn't had time to really spread into the older age groups, which are at much greater risk of severe outcomes and hospitalisation, so we may see a different pattern in hospitalisations.”

However, Professor Ferguson added that hospital admissions were still rising and it was possible that the UK could see high levels of hospitalised COVID-19 patients for some weeks.

Listen to a recording of his appearance on BBC Sounds (from 1hr 11 mins).

Omicron severity lower

Research from Imperial published before Christmas found people infected with Omicron were estimated to be 20 percent less likely to attend hospital and 40 percent less likely to require hospitalisation for a night or more,   compared to cases of the Delta variant.

However, the Imperial College London COVID-19 response team noted that the estimated reduction in severity could be balanced out by the variant’s increased transmissibility, as very large numbers of infections could still lead to large numbers of hospitalisations.   

Following the publication of the report, Professor Azra Ghani, Chair in Infectious Disease Epidemiology at Imperial told BBC Radio 4’s Today programme there were concerns about how severe the variant could be for older age groups, as cases had largely been in the younger population at the time.

She said: “It is certainly good news that [Omicron] appears to be less severe, but it does have to be balanced with the very large numbers of infections we are now seeing...

“Anything we can do to slow down that rate of increase would be enormously helpful in preventing the pressures that are in place on the NHS.”

Listen to a recording of Professor Ghani’s appearance on BBC Sounds (from 1hr 9 mins).

Scientists better prepared for future variants

Knowledge gained from the pandemic has made scientists better prepared to tackle future variants of COVID-19, an Imperial professor has said.

"I slightly suspect that there will be future variants, but I think with all that we've learned now, we actually should be able to deal with them with much greater certainty." Professor Peter Openshaw Professor of Experimental Medicine

Professor Peter Openshaw, who received a CBE for his work on immunology in the 2021 New Year Honours list, told the PA News Agency that the Omicron variant was a “very significant development” in the pandemic because it appeared to be producing more of a “common cold-like syndrome” in patients.

However, he warned that the virus was still causing “a very significant amount of serious lower respiratory tract and system disease”.

He said: “Whether there will be another variant or whether this is going to be an opportunity to really see the end of it, I don't know.

“I slightly suspect that there will be future variants, but I think with all that we've learned now about vaccinology, the immune response and how to treat COVID-19, we actually should be able to deal with future variants with much greater certainty.”