January 08, 2023

Of Covid Variants and Scariants

Prabir Purkayastha

THE news of the opening up of China from the Covid-19 protocols and its current epidemic has overtaken the threat of two emerging SARS-CoV-2 lineages – XBB and BQ.1. China is seeing the spread of BF.7, which is much closer to the original Omicron strain. Our existing immunity, from either vaccines or infections, should therefore continue to protect us from infections partially and much better against serious infections.

The threat of the Chinese variant, as the news media calls it, is much lower than that from the US and Europe. This has nothing to do with the geography of the virus: it is simply the genetic distance of these subvariants from what our bodies saw, either as vaccines or as previous infections. Eric Topol, the founder-director of Scripps Research Institute and a professor of molecular medicine there, has talked about variants of the SARS-CoV-2 virus, which we need to worry about and "scariants". Scariants are variants used to create fear and scare us but are only another strain, of which hundreds exist at any given time. In the Topol nomenclature, XBB and BQ.1 strains are variants to worry about, while the Chinese BF.7 may only be a scariant!

I am not getting into how the virus strains are named. The question here is not who is descended from who but how different these subvariants are from the original omicron strain. While BF.7, the dominant subvariant in China, is not that distant from the original omicron variant, the BQ.1 and XBB subvariants are quite distant. It also matters where the mutations are; if they are in the spike protein region, it may improve their ability to infect us. Again BQ.1 and XBB subvariants have major changes in the spike protein, meaning it has an improved ability to bypass our immunity in the initial stages of the infections.

Why should this matter to us? Eric Topol talks about three properties of any new variant. Is it more virulent? Does it cause more deaths? Or is it more infectious, transmitting more easily from person to person? Or is it more immune evasive, meaning that even if we have been either vaccinated or infected, the body's immune system does not recognise it, and we can therefore be infected again.

Initially, the success of the "new" lineages was due to greater transmissibility, the ease with which they could infect people. With a population which has now either been already infected or has received multiple vaccine doses, the success of the current variants is based on how effective they are in evading our immune system. If they are more effective in escaping our immune system than other variants, the new strain will emerge as a variant of concern among the hundreds of new subvariants that are emerging continuously.

The BQ and XBB subvariants of SARS-CoV-2 Omicron are now rapidly expanding in North America and in Europe. The journal Cell has reported a study, titled, "Alarming antibody evasion properties of rising SARS-CoV-2 BQ and XBB subvariants". The paper concludes "... that neutralisation of BQ.1, BQ.1.1, XBB, and XBB.1 by sera from vaccines (vaccinated persons: author) and infected persons was markedly impaired." This included a bivalent mRNA vaccine as well, meaning that even if a new bivalent mRNA vaccine is used, the results are not significantly different. The Cell paper continues, "Monoclonal antibodies capable of neutralising the original Omicron variant were again largely inactive against these new subvariants... Together, our findings indicate that BQ and XBB subvariants present serious threats to current COVID-19 vaccines, render inactive all authorised antibodies, and may have gained dominance in the population because of their advantage in evading antibodies."

Why is then so much noise over the Chinese BF.7, which does not appear to have the immune escape properties of the BQ.1 and XBB subvariants? Even in India, while we are focussing more on incoming passengers from China, which is also what European and the US are also doing, what are the preparations for the new subvariants? The XBB.1.5 strain has emerged in the last two weeks as the dominant strain in the US and is likely to take over globally as well.

The reason for fearing passengers from China and asking for Covid tests is that after relaxing China's zero-Covid policies, there is now an explosion of Covid in China. Therefore the need to test that Chinese passengers are free of Covid before they start their journey from China and test a sample after disembarking. While China has condemned these measures as discriminatory, they are as much political as epidemiological measures.

Before China relaxed the Covid restrictions of its zero Covid policy, the western media was campaigning about how China was wrecking its economy with this disastrous policy. Once the zero Covid policy has actually been relaxed in China, they have now gone to town on the disaster of China's lifting its Covid restrictions. Damned if you do, and damned if you don't!

China's zero Covid policy, particularly when the virus was completely new and during the delta version, saved millions of lives. When the US saw 1.1 million deaths, India 530,000, and China saw about 5,000, a minuscule number. A detailed article by Tings Chack in MR Online (mronline.org) dated January 1, 2023, has explained why China pursued its zero Covid policy. When the Covid-19 pandemic started, China, with a population five times that of the US, had only 1/10th of the ICU beds that the US had. China took the last three years to strengthen its public health infrastructure before it lifted the Covid restrictions.

The Chinese government's changing Covid-19 from a Class A to a Class B disease means the reporting becomes once a month. But with the numbers rising quickly, a lack of official numbers only fuels speculation that China is hiding its data because it is so bad and hundreds of thousands are dying. In major urban centres, where the numbers have risen steeply over the last 30 days, reports in social media of hospital collapses and overflowing mortuaries do not seem to be on a scale that we saw in Wuhan initially or in different parts of the world during the delta spikes. It will be much more helpful for China if the official numbers are released. Of course, in such a huge spike as we are now witnessing, the testing infrastructure faces tremendous problems carrying out millions of tests daily. But this is one part of China's infrastructure that should weather this storm better, as earlier, China was testing millions every day.

I expect the total number of those infected, including those who have recovered, to be in the hundreds of millions. But the peak appears to be now receding in major urban areas. There are still two challenges before China: a) handle the serious cases that peak after 2-3 weeks in urban areas, b) address the inevitable rise of numbers in rural China that will follow the urban peak. As we have written in these columns, a large number of deaths occur when the health infrastructure collapses and is overwhelmed by a very large number of serious cases. The unavailability of ICU beds and shortage of oxygen led to high death rates during our delta peak in late 2020, as it did in other parts of the world. This is the test that China will need to pass. Though China has increased its ICU beds 2.4 fold in the last three years, the high numbers of infected can still overwhelm the ICUs, particularly in the rural areas.

Everywhere, the omicron spikes produced a high number of infections. Though the deaths per 100,000 were much lower than in the delta variant, the much higher number of infections meant that in absolute terms, there was also a high number of deaths, particularly among the unvaccinated. In China, contrary to western media campaigns, most people have been vaccinated with two doses, and its booster dose numbers are higher than in countries like the US. Given that not all those vulnerable – the older population and those who are immune compromised – have received booster doses, China needs to target this section with boosters, particularly using its new adenovirus vector nasal vaccine.

We need to address the question, will the raging omicron infections in China produce new and more dangerous variants? There is no evidence that it has. The genome sequences that China is submitting to the global GISAIDs and testing of passengers from flights from China show the subvariant of BF.7 is still the dominant strain in China. This variant is much closer genetically to the omicron virus that swept the world earlier, and our immunity, both from vaccines and previous infections, should provide immunity against this strain. Though the government has issued various warnings against the Chinese subvariant BF.7, the danger – given air traffic between the US, the UK and India – is from XBB.1.5, which is rapidly emerging as the dominant strain in the US. And as we know, if the US leads, the UK and EU will surely follow!

India has successfully run clinical trials using the adenovirus vector nasal vaccine. This should rapidly be foregrounded in our Covid preparedness, not so much for the Chinese BF.7 strain but the XBB.1.5 strain. Though today, we are much better equipped in terms of knowledge on how to treat Covid-19 and its various manifestations, the challenge remains for implementing this knowledge, particularly if and when a new wave appears.