‘As of now, every global population set is vulnerable’

Omicron cases are confirmed in India. And the variant is pushing the world into yet another period of Covid-induced uncertainty. Research scientist Dr Parnali Dhar Chowdhury at the Department of Epidemiology of Johns Hopkins University, US, tells TOI that in the absence of clear instructions from WHO or other agencies, countries will do what they feel is the best strategy: Why should we be worried about Omicron even after having faced the deadly Delta strain? It’s too early to get panicked given that the amount of scientific data that we have so far is too small, but yes surely there are some genuine concerns around this new coronavirus variant. First, according to the latest data from South Africa this variant is fast overtaking its predecessor, Delta, to become the dominant variant. Second, Omicron has raised fears of a surge in global infection spread. It was first detected in South Africa last week and has already spread in 30 countries, much more rapidly than any previous variants. Last but not the least, it could be starting to trigger a new wave of infection as scientists do not yet know whether fully vaccinated individuals possess enough immunity to protect themselves from the Omicron variant. As of now, every population set across the globe is highly vulnerable to this variant’s attack. medium88056303Isn’t the high transmissibility of this variant alarming? It is true that the transmissibility of Omicron seems to be very high as within a week the virus has been found within half a dozen European countries, UK, Australia, Israel, Hong Kong, US and India. In South Africa, Omicron accounts for approximately 2,300 new daily cases in one province only. This is alarming. There’s no indication that existing vaccines won’t work. But surveillance within countries needs to be more active and is extremely critical to check the spread in a timely manner. Having said this, we must remember that hundreds of people who are travelling now may get infected and spread this variant and it will probably take weeks to know if it amounts to an inflated scare or a highly contagious new mutation to elude the existing vaccines. What methods should be adopted to determine the occurrence of this strain? Are we to go through new tests for this variant? The widely used RT-PCR test and Abbott’s rapid test continue to detect infection caused by Omicron, like other variants. As the Omicron variant contains 32 mutations to the spike protein so far, rapid test and PCR test are eligible to detect this variant as they don’t depend on the spike protein for detection. It’s important to do these tests more widely and more rapidly across the board for all travellers. Countries have rushed to impose travel bans. Are these absolutely necessary? Travel bans can’t provide 100% protection from the virus but definitely give some extra time to the scientific community to understand the extent of illness/infectivity of the new variants and help in accelerating vaccination among the unvaccinated population. The point is, as we still don’t know how infectious this Omicron variant is given its high mutation in the spike protein, and there are no clear instructions from WHO or other international agencies, it solely depends on an individual country how it wants to adjust international travel measures in a timely manner. How do we combat this new variant? It’s good news that no Omicron-related deaths have happened so far and countries have by far more tools to fight the variant today than they had at this time last year. These include expanded testing, an increase in genomic sequencing and enhanced detection of virus spread through travel. However, the most powerful tool is vaccination. It would likely take a couple of weeks to learn critical information about the Omicron variant. Until then, maximum surveillance with multiple precautionary measures, including proof of vaccination, PCR tests and quarantine among travellers and vaccination are the only tools. What’s the best way forward for India now? There is no evidence so far that Omicron is more infectious than Delta that originated in India in October 2020. During the Delta surge, India had a large unvaccinated population. We are seeing that now in South Africa, where only 24% people are fully vaccinated so far, and Omicron is dominating. Keeping this in mind, the best way for India would be to step up taking precautions. This may include vaccinating the unvaccinated population and booster dose to susceptible groups, expanded testing and enhanced detection of virus spread through travel from ‘high-risk’ countries, and increase in genomic sequencing for the next 2-4 weeks. India should also continue travel restrictions on passengers from certain high-risk African countries for the time being until we get to know more scientific information about the variant, such as its exact level of transmissibility and the extent of illness it causes.