The Omicron lineages have been named BA.4 and BA.5.

The yet-to-be peer-reviewed findings, recently posted on the preprint repository BioRxiv, show that the BA.2 sub variant may have features that make it as capable of causing serious illness as older coronavirus variants.

The guidelines released on Friday come into force from January 11 and will remain effective till further government orders.

The B.1.640.2 variant has been reported by researchers at institute IHU Mediterranee Infection in at least 12 cases, and has been linked to travel to African country Cameroon.

A third dose of COVID-19 vaccine can provide up to 88 per cent protection against hospitalisation from infection by the Omicron variant of coronavirus, according to early results from studies conducted in the UK.

Experts in Singapore, which is seeing a surge in Omicron cases, have warned that the new and supposedly more contagious variant is likely to replace Delta over the coming weeks as the dominant global variant, with the virus being fitter and having a reproductive advantage.

As the Omicron strain spreads across the globe and questions on vaccine inequity dominate discussions, scientists are still scrambling to learn more about emerging variants of the deadly virus that has claimed millions of lives and crippled economies.

Tamil Nadu, Telangana and West Bengal reported their first COVID-19 variant Omicron cases on Wednesday, four more persons each tested positive in Maharashtra and Kerala.

Eight new cases of the Omicron variant of coronavirus were reported in Maharashtra -- seven of them in Mumbai -- and none of the patients had a history of international travel, the state health department said on Tuesday.

Passengers coming from 'at-risk' countries to six major Indian airports have to compulsorily pre-book for the on-arrival RT-PCR test from December 20 onwards, the civil aviation ministry said on Tuesday.

Tottenham Hotspur recorded 13 COVID-19 cases at the club last week, while Leicester City and Manchester United were also affected by the virus.

'People who were vaccinated early on, for example, from January to April this year, namely health workers, the elderly, and the immunocompromised, should be identified for a booster dose.' 'We should start getting ready for administering booster doses to them on priority.'

The New Delhi district authorities on Monday issued a show-cause notice to Etihad Airways for allegedly violating the Centre's guidelines for international passenger arrivals at the IGI airport here, amid concerns over the Omicron variant of coronavirus.

Pakistan on Monday banned travel from 15 countries, except under certain conditions, and tightened up travel restrictions on 13 other countries in wake of the threat of the new COVID-19 variant Omicorn.

The patient is currently admitted to the Lok Nayak Jai Prakash (LNJP) Hospital and has mild symptoms, hospital officials said.

Most of those who tested positive either recently arrived from African countries or were in contact with such people.

They include a woman who came from Nigeria along with her two daughters to meet her brother in adjoining Pimpri Chinchwad area, the official said.

Samples of six other people, who tested positive for the coronavirus after arriving in Kalyan-Dombivli area of Thane district from different countries, have been sent for genome sequencing and the results are awaited, another official said.

Cases with the Omicron variant have already been detected in Karnataka and Gujarat.

"The international travellers who arrived in Mumbai from the high-risk countries have been identified and the swab samples of 28 such persons have been sent for genome sequencing. Out of them, nine persons have already tested COVID-19 positive," Health minister Rajesh Tope said.

Two cases of the new Omicron variant of coronavirus have been detected in Karnataka, the Union government said on Thursday while asking people not to panic but follow Covid-appropriate behaviour and get vaccinated without delay.

With the Maharashtra government on Thursday amending its air travel rules in view of global concerns over the Omicron variant of coronavirus, the Brihanmumbai Municipal Corporation cancelled its previous guidelines issued to the city airport authorities and asked them to follow the revised ones as issued by the state.

The government of Maharashtra on Thursday revised its guidelines for passengers arriving in the state.

Their samples have been sent to the National Centre for Disease Control for genome sequencing to ascertain if they have the new variant, Omicron, which has been classified as 'variant of concern' by the WHO.

Six Covid-19 cases were reported on Wednesday after screening 3,476 passengers of 11 flights that arrived in India from "at-risk" countries and the samples have been sent for genomic sequencing, the Health Ministry said amid concerns over the 'Omicron' variant of coronavirus.

The ministry of civil aviation on Wednesday said only two per cent of the passengers coming from countries that are not in the 'at-risk' list will be subject to random sampling for coronavirus and such passengers will be permitted to leave the airport after giving the samples.

After the Maharashtra government revised the guidelines on quarantine for international passengers in view of concerns over the Omicron variant, the Centre on Wednesday asked the state to align its order with the SOPs issued by the Union Health Ministry.

The economic impact of the Omicron variant of COVID-19 on emerging economies will depend on a mix of government restrictions, public comfort with social interactions, and capacity of governments and central banks to provide additional policy support to the private sector, Moody's Investors Service said on Wednesday. The emergence of the new variant poses new risks to the global economic growth and inflation outlook, as concerns mount about the variant's health risks and several countries have imposed new travel restrictions in recent days. These restrictions will likely increase over the coming weeks until scientists learn more about the variant, it said.

In case the test is negative, the passenger will still have to undergo seven-day home quarantine.

Strict norms for arriving international passengers, especially from 'at-risk' countries, will come into effect from Tuesday midnight and authorities are stepping their vigil for effective surveillance amid mounting concerns over the emergence of the coronavirus variant Omicron.

Union health secretary Rajesh Bhushan held a review meeting with states and Union Territories on Tuesday and advised them to ramp up testing for early identification and management of cases.

'Mortality or hospitalisation has not increased in South Africa because of the new variant.' 'There is nothing to show so far that it is more infectious.' 'I am of the opinion that at the moment, there is no reason to panic.'

Madhya Pradesh health authorities on Monday managed to trace a 34-year-old woman from Botswana, a country in southern Africa where Omicron variant of coronavirus has been detected, in Jabalpur, a day after a search was launched for her as per the health surveillance guidelines to check the spread of COVID-19.

The Omicron variant carries 'concerning' mutations that may make it more transmissible and allow it to evade immunity, scientists said on Monday, stressing that the one certainty in the uncertainty of the many things unknown is this -- COVID is not a short-term crisis and vaccines are still a critical tool.

No case of the new Omicron variant of coronavirus has been detected in India yet, a senior government official said on Monday.

The Omicron variant of Covid-19 adds new uncertainties to the global economic outlook but much will depend on its speed of transmission, hospitalisation and death rates, and also the effectiveness of vaccines, Moody's Analytics said on Monday. In its commentary titled 'Much to Learn About Omicronast', Moody's Analytics said although the variant appears to spread "remarkably quickly", it will be at least two more weeks before more will be known about this new variant. "The Omicron variant of COVID-19 adds new measures of uncertainty to the outlook for the global economy, although it is too soon to adequately quantify that risk.

South Africa will remain on the lowest 'level 1' of its five-level lockdown strategy to fight the COVID-19 pandemic despite the global panic around the detection of the Omicron variant in the country, President Cyril Ramaphosa has announced .

Alert to the looming threat from the 'Omicron' variant, states began to re-tighten curbs and urgently trace people who arrived from abroad in the last one month while a demand to not allow flights from the affected countries was made by Delhi Chief Minister Arvind Kejriwal and Karnataka Chief Minister Basavaraj Bommai.

The presence of spike protein facilitates a virus' entry into the host cell and is responsible for making it transmissible and causing infection.

As a proactive step, the government has already placed nations, where this VoC has been found, in the category of 'at risk' countries for additional follow-up measures of international travellers coming into lndia from these destinations, he said in a letter dated November 27.