Omicron variant 'Arcturus' behind fresh Covid infections in India

Experts say a new sub-variant of Omicron is probably the cause behind the sudden rise of Covid infections in India. It is triggering fears of a fourth wave in the country amidst a declining trend worldwide.

Experts say a new sub-variant of Omicron XBB1.5, named XBB 1.6 and dubbed Arcturus by experts, could be the cause of the wave in India. Dr Maria Van Kerkhove, a World Health Organisation (WHO) expert had recently said XBB.1.16 carries one more mutation in the viral spike protein compared to the XBB.1.15 variant and laboratory studies showed this mutation has made the variant more infectious, though less deadly.

"The current spike in India is caused by XBB.1.16/Arcturus and other variants in India have been replaced by XBB.1.16/Arcturus within a few months", Carmen Leitch, an expert on the virus said this week in an article in Labroots, a leading scientific social networking website. The government of India and the World Health Organisation (WHO) are yet to confirm a newly mutated virus as the reason for infections spreading rapidly in the last two weeks in India.

"Doctors in India have noted that many kids are falling ill, and they are presenting with a cough, high fever, and eye irritation called conjunctivitis, or pink eye. At this time, the cases do not appear to be more severe than those caused by previous variants", says Carmen Leitch. A pre-print report on bioRxiv journal says XBB.1.16/Arcturus can resist the effects of many antibodies that work against the virus and can better multiplicate than other Omicron variants. This variant may soon spread around the world, the researchers said.

Meanwhile, India's active caseload has increased to 53,720 as of Saturday with just over 10,000 new infections. The country had recorded 11,109 new coronavirus infections the day before, including 29 deaths on Thursday, according to the latest data from the government. The Indian Medical Association says the relaxation of Covid-appropriate behaviour like wearing masks, low testing rate and the emergence of a new variant of Covid-19 could be the reason for the new wave of infections in India.

The XBB.1.5 was spreading across the globe and that is now coming down. From 22 October 2022 to 21 February 2023, Omicron XBB.1.5 variant samples have been made available from 74 countries and most of these sequences were from the United States of America (72.2%). "Based on its genetic characteristics and available growth rate estimates, XBB.1.5 is likely to further contribute to increases in case of incidence globally. There is high-strength evidence for increased risk of transmission and moderate strength of evidence for immune escape," the WHO had said in February, which termed it as a Variant of Interest (VoI). The XBB.1.5 subvariant was called 'Kraken' by experts who track the emergence of the variants.

TAG-CO-VAC held last month in Muscat had said the booster doses of index virus-based vaccines continue to confer high levels of protection against severe disease and death caused by all SARS-CoV-2 variants, including contemporary Omicron descendent lineages.

Total active cases in a day in the country had diminished to less than 2000 by the middle of February this year. That was from the third wave peak of 2.23 lakh infections in India on January 24, last year. In the first wave during September 2020, infections had increased to over one lakh active cases and 3.69 lakh cases in the second wave on May 13, 2021. Now the daily positivity rate has touched 5.01% and the weekly positivity rate at 4.29%.

Despite the rising infection rates, India reported 359 deaths due to the virus in 2023. Of this, 110 deaths have happened since April 7. The virus has so far claimed 5,31,064 people in India since February 2020. Daily deaths were the highest during the second wave in May 2021, with over 5,000 people a day. Now the recovery rate is about 98.81%, which was only about 75% in the first wave in the middle of March 2020, when medical science had no clue how to fight the virus.

While cases in India are surging, global data from Worldometer says the disease is showing trends of waning worldwide. As of April 13, about 20.4 million active cases were there across the globe. Globally, the cases were declining after winter, as February 3 had the highest surge in active cases since January 2020 -- about 62.8 million active cases. Globally, the death rate also has come down steadily to 1.03% on April 13, 2023. In other words, 98.97% of people infected in recent days have escaped death. Since January 1, 2023, total deaths across the globe due to the disease were 1,36,355. Serious and critical cases peaked during January 17, 2021 - about 11.4 million cases. This also has come down to 39,527 cases as of April,13,2023, says the Worldometer data.