Omicron Covid-19 variant: How does it differ from Delta?

Concerns over Omicron have put nations on alert, impacting international air travel

Countries across the world are preparing to board up due to concerns about the new Covid-19 variant identified in South Africa as 'Omicron' and its ability to mutate and spread faster than other strains of the viral disease.

The World Health Organisation (WHO) has designated it as a "variant of concern" (VOC) as it has been linked to a rise in Covid-19 cases in pockets across the world. Many international travellers have tested positive with the new variant, prompting countries, including India, to review their curbs and quarantine rules.

AIIMS chief Dr Randeep Guelria said last week that Omicron has reportedly got over 30 mutations in the spike protein region, giving it the potential to develop an immunoescape mechanism, putting into question the efficacy of vaccines against this variant of the virus.

Also Read | Omicron Covid-19 variant cases inch up as the world rushes to learn more

How does it differ from the Delta variant?

Delta variant was another VOC more transmissible than its predecessors that spread across over 200 countries, including India, where it led to a deadly second wave between April and June 2021.

Scientists know that Omicron is genetically distinct from previous variants, including the Beta and Delta variants, but do not know if these genetic changes make it any more transmissible or dangerous. So far, there is no indication that the variant causes a more severe infection.

It will likely take weeks to ascertain if Omicron is more infectious and if vaccines are effective against it.

Scientists in South Africa said they had last week detected the new variant with more mutations compared with three for Beta or two for Delta. Omicron also has 26 unique spike mutations, against 10 for Delta and six for Beta. Many of them seem likely to render the variant more difficult for the immune system to recognise and thwart.

The Bambino Gesu Hospital in Rome produced the first "image" of the new strain and confirmed there were many more mutations than seen in the Delta variant. But that does not mean it is more dangerous, they said.

Much is yet to be ascertained about the virus, including whether it is more contagious, more likely to cause serious illness or more able to evade the protection from vaccines. The widely used RT-PCR tests continue to detect infections with the Omicron variant.

Also Read | Not clear yet if Omicron causes more severe disease: WHO

Which countries have reported Omicron cases so far?

The new variant has been detected in 15 countries so far. Here's a list:

Countries with Omicron variant	Number of suspected cases
South Africa
Botswana	19
Belgium	1
Hong Kong	3
Israel	2
United Kingdom	2
Netherlands	13
Germany	2
Czech Republic	1
Austria	1
Denmark	2
Australia	2
Italy	1
Canada	2
France	8

Many countries rushed to act, projecting anxiety about the further prolongation of a pandemic that has killed more than 5 million people.

Noting that the variant has already been detected in many countries and that closing borders often has had a limited effect, the World Health Organization (WHO) called for frontiers to remain open.