PUNE A study based on the genome sequencing of Covid positive samples has found that the original Omicron variant’s sub-lineage BA 2 and second-generation sub-lineage BA 1.1 – are spreading rapidly and almost neck-to-neck in their proportion of infection – when compared to the BA 2 variant which was primarily dominant in the city during the first week of January. BA 1 and BA 2 are the first-generation sub-lineage of the Omicron variant whereas BA 1.1 is the second-generation sub-lineage of the Omicron variant.
The city saw its highest peak in the third wave during the third and fourth week of January when the study found that both BA 2 and BA 1.1 are spreading almost equally while the Delta variant that was primarily responsible for the deadly second wave has reduced to just 3%.
The study, conducted by a team of researchers at Nobel Hospital, also found that those who are unvaccinated or have completed six months post the second dose and have not taken their precautionary third dose and have comorbidities could be severely infected with the Omicron variant which till now is being considered as causing only ‘milder symptoms’.
The trend was based on about 330 samples that were genome sequenced at the Pune-based Indian Institute of Science Education and Research and National Chemical Laboratories. These were the samples retrieved from the swabs of those who had either been admitted to Noble Hospital or had visited the outdoor patient department (OPD) between January 5 and 24.
Dr Ameet Dravid, internal medicine specialist who led the team at Noble hospital while undertaking 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 which may differ in their behaviour. Our study was conducted in two phases: in one, we studied about 90 samples collected between January 5 and 11 and in the second, we studied 240 samples collected between January 11 and 24. It is during the second period that the city saw its peak of the third wave which now appears to be receding but it would be too early to say that.”
{{/usCountry}}Dr Ameet Dravid, internal medicine specialist who led the team at Noble hospital while undertaking 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 which may differ in their behaviour. Our study was conducted in two phases: in one, we studied about 90 samples collected between January 5 and 11 and in the second, we studied 240 samples collected between January 11 and 24. It is during the second period that the city saw its peak of the third wave which now appears to be receding but it would be too early to say that.”
{{/usCountry}}“However, the stark 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 spreading rapidly in the second period - almost as much as BA 2 in a short span of time. Delta, which was at 9% during the first said period, went further down to just 3% in the samples we studied in the second period,” Dr Dravid said.
Dr Dravid said that the study is important as it shows a trend that in cases where BA 2 was dominant, majority of the patients had mild disease or were OPD patients while in the second phase, it was observed that although majority of the patients still had mild symptoms, they were prescribed antivirals to prevent progression of the infection if they had significant comorbidities. Dr Dravid added, “Dr Dravid added, “Out of the 12 patients serious disease or Acute Respiratory Distress Syndrome (ARDS), four were unvaccinated, eight had got both doses but not the third dose; and out of those 12, ten had BA 1 or BA 1.1 and one each had BA 2 and the Delta variant.”.”
For the patients, it clearly signifies that the expensive monoclonal antibody cocktail does not prove to be much 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 quite clear that those who do have comorbidities and have taken their second shot more than six months ago need to take their third shot four to six months after the second shot to avoid any severe complications even if they get infected with Omicron which till now has been assumed to be mild. The government needs to reconsider this and reduce the gap between the second and third dose from the current nine months to six months. People are falling ill waiting to become eligible to get the third dose.”