Where has Omicron spread, and why are scientists so concerned?

<span>Photograph: Hollie Adams/Getty Images</span>
Photograph: Hollie Adams/Getty Images

Everything you need to know about the latest Covid variant worrying scientists, and how it affects UK travel


Where has Omicron been detected so far?

Since the announcement of the first cases in South Africa, Botswana and Hong Kong earlier this week, additional cases have been reported in Belgium, Germany, Italy, the Czech Republic, Australia and the UK. All of these cases were in individuals who had recently arrived from South Africa, Mozambique or Egypt.

Dutch authorities have also been sequencing samples from 61 passengers who arrived in Amsterdam from South Africa on Friday and tested positive for Covid-19. Of these, 13 have been identified as Omicron cases.

How many UK cases have been identified, and where are they?

So far, the UK has identified three cases, two in Nottingham and Brentwood, Essex, which involved travel connections with South Africa, and a further case of an individual who was visiting the UK. Contact tracing and targeted testing at locations where these individuals were likely to have been infectious is currently under way, in order to establish further likely contacts and cases. All positive cases will undergo further genome sequencing to identify whether or not they are infected with the Omicron variant.

According to new temporary and precautionary measures set out by Boris Johnson on Saturday, all contacts of suspected Omicron cases must self-isolate, regardless of their vaccination status.

Why are we so concerned about this variant?

The Omicron variant has a large number of mutations compared with previous variants, more than 30 of which are in the spike protein – the key used by the virus to enter our body’s cells. Such a dramatic change has raised concerns that the antibodies from previous infections or vaccination may no longer be well matched, although it’s likely that some residual immunity, for example from T-cells, will remain.

Some of the same mutations have been seen in other partially vaccine-resistant variants, such as Beta and Gamma, although Omicron contains many additional mutations. Purely based on this list of mutations, scientists anticipate that the virus will be more likely to infect – or reinfect – people who have immunity to earlier variants. These are theoretical predictions, though, and studies are rapidly being conducted to test how effectively antibodies neutralise Omicron.

Also of concern is how rapidly Omicron appears to have spread within South Africa, where there has been a surge of cases in the past two weeks. More than 80% of these were from Gauteng province, and preliminary analysis suggests Omicron has rapidly become the dominant strain. There is a chance this is a statistical blip linked to a super-spreader event, but the data has triggered enough concern for precautionary measures.

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Which countries have been added to the UK’s travel “red list”?

From 4pm on Sunday, passengers arriving in England from South Africa, Botswana, Lesotho, Eswatini, Zimbabwe and Namibia will be required to book and pay for a government-approved hotel quarantine facility for 10 days. Those who have arrived since midday on Friday but before this deadline must quarantine at home for 10 days and take NHS PCR tests on days two and eight, even if they already have a booking for a lateral flow test.

The government has also added to the requirements for travellers from other countries, so all international arrivals must take a PCR test by the end of the second day after their arrival, and self-isolate until they have a negative result.

Which countries have introduced travel bans on UK passengers?

Israel has responded to the emergence of Omicron by banning all foreigners from entering the country for 14 days. Switzerland has imposed a 10-day quarantine on anyone arriving from the UK, regardless of their vaccination status. The same applies to travellers from the Czech Republic, the Netherlands, Egypt and Malawi.

Spain has also imposed restrictions on UK passengers: only those who have been fully vaccinated will be allowed in from 1 December. Previously, anyone could enter if they could show a negative PCR test taken within 72 hours before arrival.

What other rules have been brought in to contain Omicron’s spread?

Besides the new travel measures and the requirement for contacts of suspected Omicron cases to self-isolate, regardless of their vaccination status, face coverings will be made compulsory in shops and on public transport in England from Tuesday, bringing it closer in line with Scotland, Wales and Northern Ireland. Hospitality settings such as pubs and restaurants will be exempt from the change. The new measures will be reviewed in three weeks’ time, the prime minister has said.

Is there any difference in the symptoms people are reporting?

According to Dr Angelique Coetzee, who runs a private practice in Pretoria, South Africa, the Omicron patients she has seen have presented with relatively mild symptoms, and none of the loss of taste of smell typically associated with Covid-19. Instead, they have had reported unusual symptoms, such as intense fatigue and a high pulse rate. However, it is too soon to know whether these anecdotal reports will be true of everyone who is infected with Omicron.

How could it play out in the coming weeks?

Within the next month, we should have a far better idea of how contagious Omicron is, and whether or not it is associated with more severe disease. We should also know the extent to which it has been contained, or if it has spread more widely, as is expected by many scientists. Perhaps most important will be the results of those ongoing experiments to test how effectively antibodies neutralise the new variant. Real-world data on reinfection rates will also give a clearer indication of the extent of any change in immunity resistance. Until all this data is available, it makes sense to remain cautious and reimpose some restrictions to limit Omicron’s spread.