The Omicron variant continues to spread around the UK, with 274,470 new Omicron cases reported in the two weeks between 23 December 2021 and 5 January 2022.
While COVID-19 rates remain high around the UK, the government has decided that from 11 January anyone in England who receives a positive result on a COVID lateral flow test will need to self-isolate immediately, and will not require a further PCR test to confirm they have the virus.
New research has revealed that Omicron can evade the antibodies generated by vaccines or by treatments administered for COVID-19, however it is neutralised by a booster vaccine. According to the 33rd technical briefing released by the UK Health Security Agency (UKHSA), 9.5 per cent of Omicron infections have been identified to have previous confirmed infections, which they say "is likely to be a substantial underestimate of the proportion of reinfections".
The government is urging everyone eligible to get their coronavirus vaccine.
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According to data from the Office for National Statistics (ONS) released in December 2021, it would appear that infection with Omicron is less severe than Delta when comparing the number of hospitalisations per 1,000 cases.
The number of COVID-related deaths in the week ending 24 December across England and Wales was 852, while the latest figure for the week ending 31 December was 582, accounting for 6.9 per cent of all deaths in that time period.
Some however have suggested that Omicron could appear to be less severe because it is currently more concentrated in young adult age groups (20 to 29), relative to Delta.
What are the symptoms of the Omicron variant?
Reports of infection with the new variant have suggest Omicron symptoms are different to the other COVID-19 strains.
The ZOE COVID Study app, run by epidemiologist Professor Tim Spector, has analysed data from self-reporting users in December 2022, as Omicron became dominant. In comparison with data from October, when the Delta variant was dominant, the team found that the top symptoms for Omicron were a runny nose, a headache, fatigue, sneezing and a sore throat.
The ZOE team write that their analysis found "only 50 per cent of people experiencing the classic three symptoms of fever, cough, or loss of sense of smell or taste."
As with all other coronavirus strains, the Omicron variant can still cause severe disease or death, particularly for those who are clinically vulnerable.
The main symptoms of COVID-19, according to the NHS, are:
- a high temperature– this means you feel hot to touch on your chest or back (you do not need to measure your temperature)
- a new, continuous cough– this means coughing a lot for more than an hour, or three or more coughing episodes in 24 hours (if you usually have a cough, it may be worse than usual)
- a loss or change to your sense of smell or taste– this means you’ve noticed you cannot smell or taste anything, or things smell or taste different to normal
The NHS say that most people who have symptoms of COVID-19 will have at least one of the above.
Will vaccines still work against the Omicron variant?
While Omicron is thought to evade the protection offered by the first and second dose of a coronavirus vaccine, Omicron is still neutralised by the antibodies generated by a booster Pfizer dose, according to a study by researchers at the University of Paris's Vaccine Research Institute, though the impact of the booster jab was weakened compared to Delta.
A separate study by scientists in America tested the effect of a Moderna booster and found that it did neutralise Omicron, but this was "4–6-fold lower" than against the original SARS-CoV-2 first identified in Wuhan, China.
However, Dr Clive Dix, former Chair of the UK Vaccine Taskforce, has responded to the new research cautioning that "decrease in antibody neutralisation is not the same as vaccine effectiveness".
"We have seen a progressive loss of antibody neutralisation as we moved through Alpha, Beta, Gamma and Delta," Dix told the Science Media Centre.
"That no doubt leads to decrease in effectiveness against transmission and infection but to date the vaccines all protect against severe disease (including hospitalisation) and death. So, we should be optimistic that effectiveness against that latter two measures will remain. This is almost certainly due to a good durable cellular immune response which [recent studies] do not analyse.”
At the briefing with South African Minister of Health Dr Joe Phaahla, experts revealed what is known about the new strain.
Mutations to the coronavirus spike protein affect the ability of the virus to enter human cells. Of the 30 mutations found in the B.1.1.529 spike protein, several changes have been identified that are associated with resistance to antibodies from either a COVID-19 vaccine or natural immunity following prior infection.
The Omicron variant also has a deletion to a gene that is similar to one found in Alpha, Beta, Gamma and Lambda, which is thought to strengthen the virus's ability to evade immune system responses.
Is the Omicron variant more transmissible?
Professor Tulio de Oliveira, a virologist and Director of the Centre for Epidemic Response and Innovation in South Africa, spoke at a briefing on COVID-19 developments that was arranged by the South Africa department of health.
"[The B.1.1.529 variant has a] very unusual constellation of mutations," said de Oliveira at the briefing. He explained that there are around 50 mutations in the B.1.1.529 genome, 30 of which are in the spike protein. To compare, the Delta variant has 13 mutations.
Of these 30 mutations, some have been well characterised by scientists and have a known impact on transmissibility and the virus's ability to evade immunity. The new strain is known to have mutations near an area on the spike protein associated with more efficient cell entry, which means enhanced transmissibility among populations.It also has mutations that are known to increase the infectivity, fitness, and virulence of SARS-CoV-2.
However, de Oliveira said many of the mutations have been rarely seen before, and so are not fully understood.
How many cases of the Omicron variant have been detected in the UK?
On 7 January 2022 the UKHSA published data showing there had been a total of 274,470 new Omicron cases in the two weeks prior to 5 January. Since its discovery, there have been 365,376 confirmed cases of Omicron in the UK.
What other variants have been identified in the UK?
As of 7 January, there are five strains considered to be ‘of concern’ by PHE, including the Omicron, Delta and Alpha variants.
