How worrying are new Omicron variants - Professor Neil Ferguson

If variants stay at the current level of severity, restrictions and social distancing measures do not need to be re-introduced.

Speaking on BBC Radio 4's The Briefing Room, Professor Neil Ferguson, Director of the MRC Centre for Global Infectious Disease Analysis and the Jameel Institute, said: "The good news is, so long as new variants stay at Omicron levels of severity, we don’t see any particular risk of overwhelming waves of hospitalisations and deaths, so we won’t need to go back to social distancing measures."

The epidemiologist and professor of mathematical biology joined David Aaronovitch in The Briefing Room alongside other experts to discuss how worrying the latest Omicron variants, including BA.5 and BA.2.75 are and if the UK will face new restrictions. Currently, The Office for National Statistics estimates that 2.7 million people, or 1 in 25 of us, have got Coronavirus.

Omicron variants

"I don’t expect to see any sort of overwhelming wave or anything even of the same scale that we had back in November." Professor Neil Ferguson

Asked how tricky the new variants are, Professor Ferguson said: “There is more of a tendency for Omicron variants to colonise the upper respiratory tract and they are less likely to cause lower respiratory infection. Which probably explains why Omicron, all Omicron variants, are much less severe than the Delta variant."

“Omicron BA.5, and BA.4 also, is circulating in the UK, are slightly different from the previous BA.1 and BA.2 which caused waves in December and then February-March. But nowhere near as different as Omicron was from Delta.

"We expect to see some sort of wave, but there is some preliminary evidence it may even already have peaked in England. I don’t expect to see any sort of overwhelming wave or anything even of the same scale that we had back in November-December.” 

"You see headlines in some areas of the world that a variant called BA.2.75, which pops up in India, has cause for a little concern. It needs to be monitored just because of the number of mutations it has in that critical spike protein, which is the protein primarily recognised by the immune system. I think it is important that we maintain genomic surveillance to monitor these trends over time. But I’m not overly concerned: we would expect to see continuous evolution of this virus.”

Vaccinations

Professor Ferguson explains that current vaccines protect well against hospitalisation and death: "All the vaccines in use in the UK, provide a high level of protection against all variants including Omicron, including BA.5."

“Protection against infection, though, is a different story.” He explains: “These vaccines unfortunately provide very little protection against being infected Omicron, they just protect you against the severe consequences of disease.”

On how we can best use vaccines going forward, Professor Ferguson said: “Having vaccines which are slightly more adapted to the current variant would help, but more than anything it is important to top up the immunity of those who are vulnerable to severe outcomes.”

Herd immunity

Speaking about whether it is it unusual for a virus, like SARS-CoV-2, to have the ability to re-infect people, Professor Ferguson said: “I think it very much depends on the virus, but it is not unusual for coronaviruses. Coronaviruses circulate in human populations all the time, there are certain ones which have been in probably humans for hundreds of years. They are one of the major causes of the common cold.”

He pointed out that immunity wanes, the antibody levels in your blood drop over time, but also that viruses evolve: “Herd immunity is not an ‘all-or-nothing’ thing, it is an indication of a balance between immunity in the population and the transmission of whichever virus you are considering."

"We are approaching that state now with SARS-CoV-2, the virus which causes COVID, But that doesn’t mean we don’t get any infections, we will just get a lower level of what is called endemic circulation of the virus.”

The year ahead

Looking at the possibility of new social distancing restrictions being needed, Professor Ferguson said:  “At the end of the day, these are policy decisions. There is a balancing between what benefit they might give at reducing transmission versus the costs and the restrictions on freedom such measures require.”

“We have updated our modelling recently looking at scenarios for potential new variants, looking forward to the next year and how we best use vaccines. The good news is, so long as new variants stay at Omicron levels of severity, we don’t see any particular risk of overwhelming waves of hospitalisations and deaths."

We are in a good place going forward if variants stay at the current level of severity: “Taking the threshold for the introduction of such measures being the potential for the NHS to be overwhelmed, I don’t think it is going to be necessary to introduce such measures. With one very important caveat to that, and that is that we don’t get a completely left-field variant which somehow jumps in severity to something more like we had Delta last year.”

Policy decisions

We did something unprecedented: vaccinating the entire population of the country in one year. Prof Neil Ferguson

On the transition from emergency phase of the pandemic to more routine use of COVID vaccination, Professor Ferguson said: “No country has determined it’s policy yet on how it is going to transition from this emergency phase of the pandemic where we did something unprecedented: vaccinating the entire population of the country in one year. To evolve that into a more sustainable control strategy against this new virus, I think a lot of work still remains to be done.”

Listen to the full episode of BBC Radio 4 The Briefing Room on BBC Sounds (From 13m 43s).