Finally, there is evidence that the Omicron variant of the coronavirus is driving the unprecedented surge in Covid-19 cases in Mumbai and Delhi.

Genome sequencing by the Brihanmumbai Municipal Corporation has found that 141 of 375 Covid-19 samples randomly collected from Mumbai residents between December 21 and 22 had an Omicron infection. The new variant accounts for 37.6% of the sequenced samples, as first reported in None of the infected people had any travel history, officials said.

“This shows Omicron is spreading at the community level,” additional municipal commissioner Suresh Kakani told

In Delhi, the state health minister Satyendar Jain said 54% of Covid-19 samples sequenced in Delhi had Omicron. These included samples taken from international travellers as well as local residents who had no travel history.

Jain said due to the surge in new cases the government had “issued instructions to all hospitals to keep stock of medicines ready for the next three months”.

Both the cities have seen an explosion in Covid-19 cases recently, with daily cases growing 20-fold in Delhi and 10-fold in Mumbai in the past fortnight.

Mumbai on Thursday recorded 3,671 cases, up from 2,510 on Wednesday. The daily test positivity rate – or the number of positive cases per 100 samples tested – has reached 7.9% in Mumbai, indicating widespread transmission in the community.

Delhi on Thursday recorded 1,313 Covid cases on Thursday, up from 923 recorded on Wednesday.

The growth in cases in both cities is faster than seen in previous waves of the pandemic. Experts say the rest of India is likely to soon follow these trends.

Also read: In charts: Covid-19 cases surge across four metro cities, growing faster than previous waves

Community spread

Beyond the sequencing done by Mumbai’s civic body, surveillance done by Maharashtra’s state epidemiology department too has found evidence of Omicron’s presence in the community.

Thirty-eight of 382 samples taken from residents in Pune and Mumbai between December 21 to 25 were found to have an Omicron infection, shows data from the Indian Institute of Science Education and Research, which sequenced the samples.

Separately, Omicron has been detected in roughly 25% of 645 samples of international travellers and their close contacts, state health secretary Dr Pradeep Vyas said.

Maharashtra epidemiologist and state surveillance officer Dr Pradeep Awate said it is now established that Omicron is present at community level in Mumbai and Pune. “Further in-depth analysis is required to see the spread,” he said.

Awate pointed out that until a month ago, Omicron had not been found in any of the samples sequenced in Maharashtra. “From zero, its presence has increased to 10% of sequenced cases. That shows it is fast growing,” he said.

In Mumbai, as cases surge, random coronavirus surveillance has been stepped up at commuter railway stations. Photo: Indranil Mukherjee/AFP

Breakthrough infections, mild disease

About 50%-60% of Omicron cases in Maharashtra were breakthrough infections, which means fully vaccinated people were getting infected with Omicron, state surveillance officer Dr Pradeep Awate said. “But these infections are mild to moderate,” he added.

Of the 141 Mumbai residents found to be Omicron-positive in the random sampling done by the municipal corporation, 93 are fully vaccinated and three have taken one dose of the vaccine, said Dr Santosh Revankar, deputy executive health officer. Seven patients remain moderately ill and required hospitalisation, while the rest are either asymptomatic or have mild symptoms, he added.

In Delhi, none of the Omicron patients have required oxygen support, health minister Satyendar Jain said.

Future trends

With Omicron present in the community, Covid-19 cases are expected to continue growing rapidly in Delhi and Mumbai, epidemiologist Chandrakant Lahariya said. He pointed to trends seen in South Africa, where the variant was first detected in November, as well as the United Kingdom and the United States, where it is currently causing an exponential rise.

According to the World Health Organisation, cases of the Omicron variant double in 2-3 days. “The surge in cases in such a short time gives a sense of how quickly the virus is evolving and spreading,” Lahariya said.

Till December 29, 961 Omicron cases have been confirmed in India, with Delhi accounting for 263, Maharashtra 252, followed by Gujarat with 97 cases. Of the 961 confirmed cases, 641 cases continue to remain actively infected.

Lahariya said India must opt for a different strategy to deal with the new variant and refrain from any further lockdowns that could affect economic activities. “South Africa has decided to not test or isolate asymptomatic people, even if they have been exposed to infected people. India could think of a similar strategy since most cases are asymptomatic and a large population is already exposed to the virus,” he said.

This reporting was supported by a grant from the Thakur Family Foundation. Thakur Family Foundation has not exercised any editorial control over the contents of this article.