Third Covid-19 wave is here; 75% cases in metros Omicron: NTAGI's N K Arora

New variant in 81% of samples genome tested: Delhi health minister

A large chunk of Omicron cases in India have been reported from big cities, the head of the country's vaccine task force told a television (TV) channel on Monday, adding the third wave is upon us.

Mumbai, Delhi, and Kolkata have a combined 75 per cent share of infections of the highly transmissible Omicron variant of coronavirus that was first detected in South Africa in November, said N K Arora, chairman, National Technical Advisory Group on Immunisation. He has also been closely involved with the roll-out of vaccines from the very onset.

"Look at whatever variants have been genome sequenced. We got our first virus right in the first week of December. Last week, 12 per cent of the variants identified were Omicron and the week prior, it had increased to 28 per cent. It is rapidly increasing as a proportion of all the Covid infections in the country. In Mumbai, Kolkata, and Delhi, in particular, it is over 75 per cent of all the isolates now," he said.

Showing all signs of Omicron becoming the dominant coronavirus strain in India, Delhi’s Health Minister Satyendra Kumar Jain said on Monday that 81.28 per cent of all the Covid samples tested in the national Capital are of the highly transmissible Omicron variant.

Of the 187 genome sequencing reports of December 30-31, 152 people in the Capital were found Omicron-positive, Jain told the Delhi Legislative Assembly.

India’s daily count has been spiralling, with more than 33,750 cases reported in a single day as on Monday morning, and daily test positivity rate crossing 3.84 per cent. 

Delhi has seen fourfold rise in daily cases in the last week, entering the red alert category with 6.46 per cent positivity rate and over 4,000 cases and one death on Monday evening.

In what seems to be a case of New Year but old habits dying hard, worrying scenes of a milling crowd at Goa's Baga Beach had the state administration implement strict restrictions to contain Omicron. Authorities in the state issued directives to hotels, restaurants, and casinos to only allow guests with valid vaccination certificates or proof of a negative test result. Too little too late, especially when the coastal state’s positivity rate increased beyond 10 per cent. 

“Omicron is yet to fully supplant Delta. It will ascend in the big cities before becoming dominant elsewhere,” said Anurag Agarwal, scientist, Indian SARS-CoV-2 Genomics Consortium (INSACOG).

E Sreekumar, chief scientific officer, Rajiv Gandhi Centre for Biotechnology, said Omicron will replace Delta as the dominant variant, given that it is a more transmissive variant of Sars-CoV-2.  

"During the second wave, the Delta variant took four to five months to displace the existing variant in circulation. In the case of Omicron, this could be quicker. More so, in places where there is overcrowding," said Sreekumar. 

Sreekumar also felt it is likely that Omicron is affecting the Delta-naïve population here. If that is the case, the run of Omicron could be short-lived, given that many in India have been exposed to the Delta variant. "The crazy Omicron surge could peak soon, but the virus is unpredictable and the wave will ebb just as quickly," he added.

For those reinfected, there is no proper analysis whether they had been infected with Delta or some other variant, he added.  

Rising positivity is one of the factors being considered for stricter restrictions on public movement. The other two being cumulative new positive cases and the average oxygenated bed occupancy. 

The graded response action plan at the level of over 5 per cent positivity for two consecutive days, according to the Delhi Disaster Management Authority, will involve the closure of shops, malls, restaurants, weekly markets, banquet halls, salons, spas, and gyms. The delivery of essential items and takeaways from restaurants, however, will be allowed. 

However, Delhi has still not sounded the amber alert because of low levels of hospitalisation and serious cases. 

But the Department of Personnel & Training is taking no chances. It tweeted on Monday saying, "Keeping in view the rise in #Covid cases in the last few days, the biometric attendance for government officials and employees is being suspended with immediate effect, till further orders."

Omicron, considered three to four times more transmissible than Delta, has become the dominant strain in many countries in Europe and the US.  

In the UK, for instance, as on December 27, more than 59 per cent cases (seven-day rolling average) genome sequenced were of the Omicron lineage, displaying significant growth advantage over Delta. The same number for South Africa was much higher at 96 per cent. 

Closer home, officials have insisted that Delta is still the dominant strain, even while stating that the recent spike in cases could be due to a possible spurt of Omicron infections. The data on the overall percentage of Omicron cases - as part of the total samples sequenced - has not been made available by the health ministry yet. 

As on Monday morning, there were 1,700 cases of Omicron detected in the country, most of which were in Maharashtra, followed by Delhi. 

 Iqbal Singh Chahal, commissioner of Brihanmumbai Municipal Corporation, said around 80 per cent of the cases in Mumbai is due to the Omicron variant, as reported by task force doctors. "This may touch 90 per cent in the next few days," he said on TV.

Addressing a media briefing last Thursday, Lav Agarwal, joint secretary, health ministry, said, “The dominant strain in India today is the Delta. INSACOG is conducting genome sequencing, and we have seen Omicron cases on the rise.” 

There is now clear experimental and clinical data supporting the very high immune escape potential of Omicron, which appears to be the major component of its growth advantage over Delta, according to INSACOG.