Omicron displaced Delta as dominant variant in India in less than a month

Other countries with high daily Covid cases have seen similar surge

It took only 28 days for the share of the Omicron variant in India’s analysed Covid-19 cases to surge from under two per cent of cases to over 75 per cent.

Omicron accounted for 1.88 per cent of samples analysed in mid-December, shows data collated from Our World in Data, which collected the numbers from genomic data collection initiative GISAID. This rose to 78.55 per cent by early-January. The share of the Delta variant dropped from 89.25 per cent to 20.85 per cent in the same period. The November 29th share for the Delta variant was 94.63 per cent compared to 0.51 per cent for Omicron.

The top five countries that Omicron affected the most accounted for 1 million cases a day on a seven-day moving average basis as of the week ending Sunday, January 23. India alone accounted for over 300,000 daily cases. The number of rolling seven-day moving average of daily cases went up from under 8,000 on December 13 to over 130,000 on January 10th, the last day for which the sequencing data is available on the website.

GISAID also provides data on the share of variants in other countries. Omicron is the dominant strain in all five of the countries which have the highest number of daily cases. This includes the United States of America, Brazil, India, France and Italy. Each country has found between 70-95 per cent of samples analysed belong to the Omicron variant.

The proportion may well have gone up since. Other countries have reported higher shares of Omicron. France and Italy both have in excess of 90 per cent Omicron share. It is 91.91 per cent for France. The Italy number is 90.82 per cent. These two were the only countries in the top five that had a lower Omicron share than India. The highest Omicron share is in the United States of the five. It had over 98.21 per cent share.

The data shows the share of analysed sequences in the preceding two weeks. It may not be exactly representative since only a small number of cases undergo this kind of sequencing.  

The Indian SARS-CoV-2 Genomics Consortium (INSACOG), a government-led consortium of labs analysing Covid-19 cases, reportedly released the January 10 data only on Sunday, January 23.

“Omicron is now in community transmission in India and has become dominant in multiple metros, where new cases have been rising exponentially....While most Omicron cases so far have been asymptomatic or mild, hospitalizations and ICU cases have been increasing in the current wave. The threat level remains unchanged,” it said in its weekly bulletin.