Editorial: Subvariant spillover

Earlier this week, India reported as many as 9,111 new coronavirus infections, while active cases have surged to 60,313 as per Union Health Ministry data, updated as on Monday.

Just about one week ago, the country witnessed 7,830 fresh cases, which was reported as the highest in over seven months or 200 days. While 24 fatalities were reported nationwide over the past 24 hours, the death toll from COVID has been updated to 5.31 lakh as of April 17.

The doubling of the infection tally over the last week, has pushed up the daily positivity rate to 8.40%, and the weekly positivity rate to 4.94%. Tamil Nadu also reported 521 new cases at the start of this week, which took its test positivity rate to 8.6%.

The latest Omicron variant of interest around the world is known as XBB.1.16, named ‘Arcturus’ by virologists. It is known to be the fastest spreading Omicron subvariant, which is also responsible for the latest rise in cases, as per experts in the healthcare space.

Amidst the surge, 436 cases of the XBB.1.16.1, a mutated subvariant of Arcturus were also detected in the country. A top Health Ministry official however downplayed the risk of XBB.1.16, stating that the severity of the variant is currently below average and led to fewer hospitalisations.

Having said, virologists are expecting a further rise in cases over the next eight to 10 days after which they expect a decline in numbers. What is interesting to note is the messaging issued by the government, which believes that the current surge is not a wave, but rather an endemic cycle of the coronavirus.

And although Omicron and its subvariants continue to dominate, a majority of the assigned variants, have an insignificant severity of disease.

At this point in time, questions are also being raised on whether the existing vaccines based on the SARS-CoV-2 virus, which was first reported in China, would still be effective in the war against newer versions of the same virus. Immunologists have pointed out that the levels of freshly-made antibodies, created by an antigen-encounter, introduced to the body, during vaccination tend to dip within a matter of three months. It is this gradual drop which is responsible for individuals getting infected despite vaccination and multiple booster doses.

Healthcare practitioners have also highlighted the infeasibility of repeatedly inoculating the population, every four or six months, in an attempt to keep the antibody levels perpetually high.

There’s also a school of thought which seeks to update first generation vaccines using parts procured from recent iterations of the virus such as the Omicron.

But the in-practice performance of updated mRNA boosters is nowhere near the expectations set by lab study scenarios. And it’s also the reason why it might not be practical to create a vaccine for every new subvariant that pops up in the COVID family.

Currently, over 220.66 cr doses of the COVID vaccine have been administered all over India.

The majority of these doses are the secondary shots at 95.21 cr doses, and 22.87 crore doses fall under precautionary doses. Right now, there seems to be a requirement to emphasise on the booster shots for those left out of the bracket, especially the most vulnerable individuals.

While health systems cannot afford complacency, there is a certain reassurance that the previous surges have prepared facilities to tackle crises in an efficient and effective manner.