Omicron variant: Study finds BA 1.1 rapidly spreading to take BA 2

PUNE A study based on the genome sequence of Covid-positive samples found that the original Omicron variant sub-lineage BA 2 and second-generation sub-lineage BA 1.1 – rapidly and almost neck-to-neck spread in their share of infection – as compared to the BA 2 variant which was primarily dominant in the city in the first week of January. BA 1 and BA 2 are the first-generation sub-lineage of the Omicron variant while BA 1.1 is the second-generation sub-lineage of the Omicron variant.

The city saw its highest peak in the third wave in the third and fourth weeks of January when the study found that both BA 2 and BA 1.1 spread almost equally, while the Delta variant that was primarily responsible for the lethal second wave has been reduced to just 3%.

The study, conducted by a team of researchers at the Nobel Hospital, also found that those who are unintentional or have completed the second dose six months after failing to take their precautions and have comorbidities, can be severely infected with the Omicron variant hitherto considered to cause only ‘milder symptoms’.

The trend was based on about 330 samples that were genome sequences at the Pune-based Indian Institute of Science Education and Research and National Chemical Laboratories. These were the samples picked up from the swabs of those who had either been admitted to Noble Hospital or had visited the Outpatient Department (OPD) between 5 and 24 January.

Dr Ameet Dravid, specialist in internal medicine who led the team at Noble Hospital in conducting the study, said: “To understand in simpler terms, Omicron is the parent, while BA 1 and BA 2 are the daughters and BA 1.1 is the daughter of BA 1. While all are from the Omicron variant family, they have specific mutations that may differ in their behavior.Our study was conducted in two phases: in one study we collected about 90 samples between 5 and January 11 and in the second we studied 240 samples collected between January 11 and 24. It is in the second period that the city saw its peak of the third wave which now seems to be returning, but it would be too be early to say that.

However, the sharp difference between the two periods is that while in the first period BA 2, which is more transmissible than the original variant but milder to treat was dominant, BA 1.1 was rapid in the second period – almost “as much as BA 2 in a short time. Delta, which was at 9% in the first mentioned period, went further down to only 3% in the samples we studied in the second period,” said Dr. Dravid.

Dr Dravid said the study is important because it shows a trend that in cases where BA 2 was dominant, the majority of patients had mild illness or were OPD patients, while in the second phase, it It was observed that although the majority of patients still had mild symptoms, they were prescribed antiviral to prevent progression of the infection if they had significant comorbidities. Dr Dravid added, “Of the 12 patients with serious illness such as Acute Respiratory Distress Syndrome (ARDS), four were unvaccinated, eight had received both doses but not the third dose; and of those 12, ten had BA 1 or BA 1.1 and one each had BA 2 and the Delta variant. ”

For the patients, this clearly means that the expensive monoclonal antibody cocktail does not appear to be very effective in case of those infected with Omicon, while it works well among those infected with the Delta variant. Dr Dravid also said: “It is clear that those who have comorbidities and took their second shot more than six months ago should take their third shot four to six months after the second shot to avoid serious complications, even if they get infected with Omicron which has been mildly accepted so far.The government needs to reconsider this and reduce the gap between the second and third dose of the current nine months to six months.People get sick and wait to be eligible to come for the third dose.


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