Everything we know so far about the Omicron COVID-19 variant

Scientists in South Africa and around the world are working at pace to discover more about a newly identified strain of the COVID-19 virus.

On November 26th the World Health Organization (WHO) designated variant B.1.1.529 as a 'variant of concern' and named it Omicron.

The decision to classify Omicron as a variant of concern was based on evidence presented to the WHO's Technical Advisory Group on Virus Evolution. This evidence suggested the new variant has several mutations that could impact how easily it spreads, the severity of illness it may cause and, crucially, the effectiveness of existing COVID-19 vaccines. This is what we know so far about Omicron:

The WHO says it's not yet clear if the Omicron variant is spread from person-to-person more easily than other variants, including Delta. The number of people testing positive for COVID-19 has risen in the area of South Africa where Omicron was first identified. More research is being carried out to determine whether this is due to Omicron, or to other factors.

Early data from South Africa shows the rate of hospitalization is rising among COVID-19 patients. However, there is no evidence so far that directly links infection with Omicron with an increased need for hospital treatment. The WHO says the rise in hospitalizations may be due to a general rise in infection rates. Many of the early Omicron cases reported in South Africa were among students. With other COVID-19 variants, younger people have generally had milder symptoms. There is currently no evidence to suggest Omicron symptoms are different, but it will likely take weeks to determine if Omicron causes more severe illness among the general population.

The WHO says it's working with partners to understand the potential impact of Omicron variant on the effectiveness of vaccines and other COVID-19 countermeasures. Corticosteroids and IL6 Receptor Blockers will still be effective against severe disease, the WHO advises. As research continues, the WHO is reminding people that vaccines remain effective against other COVID-19 variants - including the dominant Delta strain - and are the best way to avoid severe disease and death.

Preliminary research shows the new variant may increase the risk of reinfection for people who have already had COVID-19, according to the WHO. However, data is currently limited and more information should be made available in the coming days. In terms of testing for infections, existing PCR tests are effective at detecting the Omicron variant.

The WHO is reminding people that the best way to stop the spread of COVID-19 is to socially distance, staying at least 1m from others; wear a well-fitting mask; open windows to improve ventilation; avoid poorly ventilated or crowded spaces; keep hands clean; cough or sneeze into a bent elbow or tissue; and get vaccinated when it’s your turn.

In the days since scientists in South Africa identified the Omicron variant, cases have been reported in a number of countries around the world.

An outbreak in Portugal has been traced to a soccer club. The Netherlands, Denmark and Australia have also reported their first cases. Earlier, cases were reported in Switzerland, Belgium and the UK.

A number of countries are tightening travel and entry restrictions after the WHO warned on Monday of a global risk of a surge in infections, Reuters reported. Japan said on Monday it would shut its borders to foreigners from midnight to prevent a spread of the Omicron variant there. Israel on Saturday became the first country to shut its borders completely in response to Omicron. The U.S. Centers for Disease Control and Prevention (CDC) and the State Department on Saturday advised against travel to eight southern African countries.