Omicron: New coronavirus variant

By Dr. B.J.C. Perera

MBBS(Cey), DCH(Cey), DCH(Eng), MD(Paed), MRCP(UK), FRCP(Edin), FRCP(Lon), FRCPCH(UK), FSLCPaed, FCCP, Hony FRCPCH(UK), Hony. FCGP(SL)

There does not seem to be an end to the woes caused by this potentially noxious nasty bug of a coronavirus that is the causative organism of the disease COVID-19. The latest is the emergence of a brand-new variant that has been found to spread at frightening speed. It has already started to wreak havoc in many countries. Many scientists and researchers are of the opinion that this new variant is the one that causes most concern since the arrival of the Delta variant which caused relentless waves of the disease in many countries in the not-too-distant past. The emergence of the new variant has led to grave concerns all over the world although not much is known about it. The sheer lack of adequate information on this variant has left all somewhat confused and has instilled in the general populace fear of impending doom.

The variant under discussion has the scientific designation of B.1.1.529. These technical labels are rather cumbersome and the World Health Organisation (WHO), in May 2021, started naming the variants of the coronavirus that cause COVID-19, using letters of the Greek alphabet rather than the awkward scientific tags. The new variant has been designated the 15th letter of the Greek alphabet, ‘Omicron’, with the alphabetical label ‘Oo’, for general use. Omicron is pronounced ‘Oh-my-kron’ or ‘Omi-kron’. The symbol literally means ‘little O’. The WHO declared it as a ‘variant of concern’ or VOC in November 2021.

One of the most disturbing things about the coronavirus is that it constantly mutates. Many new variants of the virus have emerged over the past year and a half, and more new strains could appear in the future. As the virus replicates and spreads more rapidly, the chances of developing mutations that lead to the emergence of new variants increase proportionately. After a brief respite from the considerable problems caused by the Delta variant, Omicron has been declared as the latest VOC by the WHO due to its high number of mutations. The earliest sample of the variant is said to have been detected in Botswana on November 11, 2021.

It has now been linked to a fresh surge in infections in parts of South Africa. So far, Omicron has been reported in travellers to Belgium, Hong Kong, and Israel, apart from South Africa. Other variants of concern, including Beta, were also first detected in South Africa. According to reports as at the time of writing this article, the new variant Omicron has been detected in over 100 countries. It is spreading considerably fast in Africa, some European countries and also in the United States of America. From the time of its first detection, over 150,000 positive cases have been detected in just one month. The real number may be considerably higher as these numbers represent only those who have been tested and sophisticated tests are required to categorise detections and to confirm which ones are infected with the Omicron variant. A few cases have been detected in Sri Lanka and when one states ‘few’ it is only those who have been subjected to special tests such as gene sequencing, that need to be performed before a particular strain could be definitely categorised as the Omicron variant of the coronavirus.

It is not quite clear as yet whether Omicron will replace Delta, but scientists say that it will be a few weeks before they can clearly define the type of disease this variant causes and understand for sure as to how contagious it is. As with other variants, some infected people display no symptoms. Early evidence, however, suggests that Omicron has an increased risk of reinfection compared with other highly transmissible variants. This means that people who had contracted COVID-19 and recovered from it could be at some risk of catching it again.

Why do new COVID-19 variants keep showing up? Will existing vaccines work against it? The biggest question on everyone’s mind is whether protection from the current COVID-19 vaccines will hold up against the Omicron variant as well. Also, will people previously infected with the coronavirus be immune to reinfection with the new variant? While scientists don’t yet have clear answers to those questions, they have said that the Omicron variant has over 30 mutations in the part of the virus that existing vaccines target; more than double the number carried by Delta. This may reduce vaccine efficiency, they say. However, these are all theoretical predictions, and studies are being conducted to determine how effectively antibodies neutralise the new variant. Medical experts do not expect Omicron to go entirely unrecognised by existing antibodies.

It has been suggested that the actual disease caused by the Omicron variant is perhaps milder than that caused by earlier strains. However, this contention should not be taken at face value as there are several other confounding factors which may play a part as far as the severity of the disease is concerned. The variant emerged at a time when the entire immune profile of the populations in many countries may have changed significantly either due to recovery from earlier strains of the virus or due to significant levels of vaccination against COVID-19. Yet for all that, an important aspect that needs to be considered is how the new variant would behave in susceptible people over the age of 60 and those with other coexisting morbidities such as diabetes, high blood pressure, kidney disease and lung disorders, particularly if and when these comorbidities are not under control.

At this point in time, no robust information is available on the severity of infections the new variant causes or whether it leads to a change in COVID-19 symptoms. It will take several weeks before clear data is available to determine this. Though the Omicron variant is thought to be more transmissible and somewhat resistant to vaccines than other variants, we are not absolutely sure of anything right now. However, if required, existing vaccines could be updated to deal with the Omicron variant. That would require several trials, and it might take four to six months for the updated vaccines to be widely available. Will it spread everywhere in the world? Given that this new variant has proven to be highly transmissible, it is quite likely to have spread to many countries undetected. Health experts warn that there is no reason to overreact or panic over this new variant, as its main characteristics and potential threats are still under investigation. All experts continue to stress that vaccination remains critically important, as all real-time data suggests that it protects against hospitalisation and death. Moreover, it also considerably reduces the strain on health systems. If anything, the emergence of the new variant indicates that the COVID-19 pandemic will perhaps not end until we reach high rates of global vaccination.

Scientists are now trying to model Omicron’s global trajectory, which depends on two factors. One is its innate contagiousness, or transmissibility. The second is its capacity to evade the human immune system. Determining how much transmissibility and immune evasion contribute to the variant’s spread is what will allow us to predict how many people Omicron might infect and how fast at that.

Transmissibility reflects the virus’s ability to replicate in human cells and move from person to person. It depends on all sorts of biological processes. Does it bind more easily to receptors in people’s lungs? Do you shed it more efficiently and spew more of it out so you can infect more people? Immune system evasion, on the other hand, is the capacity of the virus to avoid antibodies that would otherwise mark it for destruction by the body, as well as an ability to dodge various immune system cells.

A key step in gauging a virus’s spread is to start with one infected person and estimate how many other people will contract the virus from that individual. In an ongoing pandemic, scientists try to capture that estimate with a value called the effective reproduction number, or Rt. The variable ‘t’ represents the number of secondary infections and depends on the effects of other people’s immunity, seasonal weather patterns, public health interventions and other limits on viral transmission. Rt can change from minute to minute depending on real-world conditions. We use it to determine how fast an outbreak is growing, or shrinking. A value of R2, for instance, means that one person will infect two others while a value of R5 means the person will spread the virus to five individuals, increasing the number of infected people much faster.

Rt estimates for Omicron are now beginning to emerge. On December 9, South Africa’s National Institute for Communicable Diseases (NICD) reported that by early November, Rt in that country had stabilised at values below one, signifying cases were actually falling during a period when Delta was the dominant variant and it was up against widespread immunity in the population. But then Rt shot up suddenly in mid-November. It is now greater than 2 throughout most of the country and exceeds 2.5 in some of the more densely populated provinces. Scientists in the United Kingdom’s Health Security Agency have since reported an Rt of 3.7 for Omicron itself. That disturbingly high number, presented in a technical briefing released on December 10, is based in part on data showing that Omicron infections in the UK are doubling every three days. At that pace, Omicron presents a much larger threat in terms of case counts than Delta.

Lastly, it is important to remember that experts are still learning on the go, and that what we know today may not represent the full picture, or may not even be valid tomorrow. Omicron, the new COVID-19 variant, may prove ultimately to have the potential to set us back to square one in the fight against the pandemic. Mutations thrive in populations where the virus is able to spread unhindered. By hoarding vaccines and leaving much of the world unprotected, rich countries have created the perfect recipe for variants. Despite world leaders’ promises to share doses and vaccinate the world, only a fraction of what is needed has been delivered. While rich countries are focused on booster shots and closing borders again, less than three percent of people living in poorer countries are fully vaccinated.

We are all fed up with COVID-19 and want to get on with our lives without this blight. We want to read about it in history books, not on our news feeds. However, the longer world leaders continue to drag their feet, the longer we will be stuck in this never-ending cycle of variants, boosters, lockdowns and travel bans. This needs to be the wakeup call that pushes world leaders to finally act. Right now, rich nations are discussing a coordinated response to the Omicron variant. We need to remind them that viruses do not care about borders and continents. The only way out is to make vaccines available everywhere and to everyone. We want 2022 to be the year we can feel confident about waving goodbye to COVID-19 for good. Together, we can make that happen. We need to ask leaders to do what it takes to end the pandemic once and for all. To escape an endless cycle of variants, boosters, and restrictions, everyone must have equal access to vaccines, no matter where they live. Such a response also needs to be rapid. Unfortunately, time is not on our side.

(The writer is a Specialist Consultant Paediatrician and Honorary Senior Fellow, Postgraduate Institute of Medicine, University of Colombo)