Omicron, Delta driving 3rd COVID-19 wave in Kolkata and Bengal: Experts

Delta constitutes a large number of the current infections but Omicron will soon take over as the dominant COVID-19 variant in Kolkata and West Bengal, say experts

By Jayanta Basu
Published: Tuesday 04 January 2022

Crowds at Kolkata's famous Park Street on Christmas.The third wave of the novel coronavirus disease (COVID-19) in Kolkata and the rest of West Bengal is being triggered by the new variant omicron, along with the previous delta variant, a section of health experts have said.

The experts said the astronomical rise in the number of cases in a short span of time, less severe infection as well as the fact that a large number of people were being affected despite taking two doses of COVID-19 vaccines pointed to omicron’s role.

Omicron is known to have the ability to bypass immunity imparted by vaccines administered so far.

Data from the Kolkata Municipal Corporation (KMC) has shown that more than two-thirds of the people found affected per day, since the middle of November, were found to have complete vaccination.

“Close to 70 per cent of the positive patients till mid-November had complete vaccination which shows that the immunity in many has apparently gone down,” Tapan Mukherjee, a senior health advisor of the KMC, said.

Another expert linked to the KMC pointed out that a few days’ ago, 21 of 22 hospitalisations among patients tested in KMC facilities had complete vaccination.

“Definitely omicron seems to be the major trigger for such an astronomical rise within a short period. But we have to accept that mass violation of COVID-19 protocols during Christmas and also the election process before that, has made its job easy,” Ajoy Sarkar, a frontline COVID-19 physician from Peerless Hospital, told this reporter.

“The mega violation during Christmas cannot be the only reason behind this sharp spike. Such a rapid increase can only happen if a new variant starts transmitting within the community,” Arup Haldar, a pulmonologist and COVID-19 physician, said.

Haldar drew a comparison with the UK where omicron very quickly pushed out delta as the major strain.

“At the beginning of December, omicron was hardly found in the UK’s virus mix. But by the month-end, it was around 90 per cent of the mix, underscoring its ability to quickly dethrone delta, which may be happening here as well,” he said.

NK Arora, head of the central task force on COVID-19, said January 3, 2022 that the omicron variant was responsible for nearly 75 per cent of the current infections causing the third wave in the metro cities of the country including Kolkata.

Delta also playing a role

A number of health experts also pointed that the delta variant too was playing a major role in the current surge in the number of cases.

“Omicron is definitely responsible. But I feel the delta variant has played the major role in the latest spike as people, at large, have completely ignored COVID-19 protocols during the Christmas celebrations,” Anirban Dalui, a public health expert associated with the state health department, told this reporter.

Sukumar Mukherjee, a senior physician and member of West Bengal’s COVID-19 advisory committee, also agreed that the delta variant was the key trigger in the latest rise.

“The number of omicron patients is still low and most of them have external travel history, which vindicates the still-strong role of delta. Also, omicron has entered Kolkata later as compared to other metro cities,” Mukherjee said.

“Be it delta or omicron or for that matter any other variant, you have to maintain the COVID-19 protocols in public places. We completely ignored them during the Christmas celebration and have virtually invited the latest wave,” Mukherjee said.

Sources in the National Institute of Biomedical Genomics, one of the key units in the ‘Indian SARS-CoV-2 Genomics Consortium (INSACOG)’ set up to monitor the genomic variations in the SARS-CoV-2 within India, pointed out that delta variants were still dominating within samples being analysed in the state.

“Till now, delta variants are the dominant ones within samples coming from Kolkata and elsewhere in the state. But we have just started to study the samples coming after the spike started around Christmas. Their results will come later this week,” a senior scientist associated with the genome study said on Janurary 3.

Dalui, however, predicted that within a short duration, omicron may take over as the dominant variant in Kolkata as is already happening in cities like Delhi and Mumbai.

Sharp spike  

Kolkata has recorded an unprecedented steep rise of COVID-19 cases during the last one week, with two out of every five tested persons found positive. The statistic was one in about 20 even a fortnight back.

Kolkata’s positivity rate on January 2 — 33.13 per cent — was much higher than the corresponding rates in Mumbai and Delhi, which were around 13 per cent in Mumbai and 6.5 in Delhi.

The rate shot further up to 38.02 per cent in Kolkata January 3. A positivity rate of 5 per cent is considered safe by the World Health Organization.

However, a report released by the Union health ministry January 3 showed that while Mumbai and Delhi had 510 and 351 omicron cases respectively so far, Kolkata had only 20 cases.   

The positivity rate in West Bengal jumped to 19.59 per cent January 3, from 1.42 per cent December 23 — a 14-fold rise within 12 days.

The state government has imposed fresh restrictions including a complete closure of educational institutes, restricting the number of passengers in offices, transport as well as during any social, cultural and religious events, besides stopping local train movement beyond 10 pm in night.

On January 3, the total number of cases recorded in West Bengal was 6,078, rising from 439 a week back on December 27.

A senior official in the state health administration recently stated during an internal meeting that the ongoing spike may reach the range of 35,000 cases per day, another official who attended the meeting, told this reporter.

The spike was around 21,000 during the second wave.

Almost all experts this reporter spoke with, confirmed that the patients afflicted in the latest spike seem to have less severe symptoms compared to the earlier wave.

The doctors expressed hope that the situation would improve with new sets of medicines emerging. But they pointed out that booster doses need to be taken at the earliest as available.  

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