Why Omicron may be more dangerous than Delta but it won’t be the last

We have to keep our surveillance high and any new potentially harmful variant should immediately be flagged rather than brushed under the carpet

Dr Aishwarya R and Dr Neeraj Nischal November 30, 2021 11:15:04 IST
Why Omicron may be more dangerous than Delta but it won’t be the last

A petrol attendant stands next to a newspaper headline in Pretoria, South Africa, on 27 November. AP Photo/Denis Farrell

Nearly two years into the battle, COVID-19 is still a global concern, currently being one of the leading causes of death in Europe and Central Asia. At the moment close to three-fourths of all new COVID-19 cases worldwide are being reported from Europe. This dangerous surge if not intercepted is expected to cause half a million additional deaths in three months’ time. One may ask as to what went wrong when it seemed like we finally had an upper hand against the virus? It boils down to an interplay of various factors, some unique to the European region, which may be responsible for this steep rise in cases.

Shortly before this resurgence, many countries were seen to relax social restrictions and Covid norms. England witnessed one of the fastest vaccine roll-outs following which the COVID-19 restrictions were revoked on 19 July 2021. Other countries such as Wales, Scotland and Northern Ireland lifted off COVID-19 restrictions in quick succession which brought a false sense of security and confidence that the pandemic was over, which unfortunately was not the case.

With the winter setting in, there would be a change in human behaviour with a preference to stay indoors with reduced ventilation. This could be conducive for the transmission of many respiratory viral conditions including COVID-19(air-borne transmission now being considered an important route of transmission). Unlike last year’s winter when the COVID wave peaked around December-January, it seems to have struck earlier this year.

This could be partly owing to the new strain circulating in the region, with more than 99 percent of isolates in the current wave attributable to this more potent Delta strain. The virus is dependent on the human host for its existence and obeys the Darwinian evolutionary theory — survival of the fittest. The virus is continually trying to evolve. This evolution is not aimed at annihilating the human race, but at coexisting with humans, as viruses are smart enough to recognise that they are not capable of replicating independently outside the host.

An equilibrium state will be achieved when they can replicate and infect humans with ease, without causing significant symptomatic disease. Until then, numerous new mutants are bound to be encountered. The variant that can evade the immune response and replicate quickly would get preferentially selected out and cause a new outbreak.

The mutant delta strain (B.1.617.2) that wreaked havoc in many countries including India in 2020-21, has mutations in its spike protein that render it highly transmissible, capable of causing severe disease, and possibly even partially suppressing the immune responses generated in an already vaccinated host.

In the WHO European region, on average 53.5 percent people had reportedly completed their COVID-19 vaccine schedule. Delving deeper into the numbers, we find that the vaccination coverage ranges between 10 percent and 80 percent between countries. Certain inherent factors such as vaccine hesitancy due to personal beliefs do influence vaccine take up. From a public health perspective, in order to break the transmission of a virus transmitted by the aerosol route, we should target to achieve herd immunity in at least 85-90 percent of the population, as is done in regards to measles.

With multiple Covid-19 waves in quick succession, achieving this target with limited time is a Herculean task. Community-wide vaccination drives, mandatory vaccination policies, Covid-passport or restricting unvaccinated people from travelling are a few measures taken by different countries in this direction. However, this has not been received well by all.

In various parts of Europe, people have gathered to demonstrate their protest against vaccination and COVID-19 restrictions. While some of them may be misinformed, many are unaware of the scientific reasons for such impositions. This not only demoralises the faith in the healthcare system and governments but also impacts vaccine uptake further.

People have been misled to believe that vaccines are a sham. Some may argue that despite effective vaccination strategies with close to 80 percent coverage the delta variant has caused an alarming surge in cases in the European region. If we look at the UK’s statistics carefully, in the previous wave when less than 10 percent of the population were vaccinated, at a time when 50,000 new cases were reported every day, the death toll ranged between 1,200 and 1,600 per day.

On the contrary, in the current wave, despite the surge in number of new cases to 50,000 per day, the reported deaths remain at 160 per day. This is indeed the result of a successful vaccination attempt in the face of Delta COVID-19 wave.

The masses need to be educated that the current Covid-19 vaccines may not prevent the occurrence of the infection always, but it definitely saves lives by reducing the intensity and severity of illness. Vaccinated people can still harbour the virus in their respiratory tracts and transmit it to the unvaccinated vulnerables, thereby warranting universal immunisation and not just targeting high-risk groups.

Vaccination hesitancy and anti-vaccine protests break this attempt in herd immunity. Moreover, non-adherence to masks and social distancing further threatens the entire community. It has been observed that only around 50 percent of people in the European region followed social COVID-19 appropriate behaviour as per WHO, which is appallingly low.

The case surge seen in Europe, Germany and the US is a prelude that as per predictions, more new variants and waves will strike. The new South African Omicron variant with numerous mutations and high replicative potential is suspected to be capable of evading vaccine immunity and being highly contagious.

This is not the first and will not be the last time that we are encountering a mutant variant with the potential to wreak havoc. We have to keep our surveillance high and any new potentially harmful variant should immediately be flagged rather than brushed under the carpet. Countries reporting new harmful variants should not be discriminated against; else, it will prove a recipe for disaster.

Another important aspect to consider would be waning immunity to COVID-19 and its vaccines especially in the context of new emerging variants. Studies have shown that the antibody response to the vaccine may dwindle to considerably low levels after six months in many people, albeit with a relatively preserved T-cell arm which is one of the key drivers in directing immune responses. The European vaccination drive began 10 months ago, leaving many with waning vaccine immunity exposed to the ongoing wave.

India has adopted a nationwide free vaccination drive and has successfully administered over a billion doses at a commendable pace. At the peak of the programme, 25 million doses were administered on a single day, which roughly corresponds to the entire population of Australia. Our target is to vaccinate 940 million adults by the end of 2021, with hopes to avert another destructive wave. Experts are contemplating the need and benefit of a booster dose, or a vaccine based on a different platform to augment the immune response to protective levels. In order to be effective against the emerging new variants, the booster doses should be a planned decision and not just a knee-jerk reaction along the lines of the Western world.

Our topmost priority should be to ensure that everyone is vaccinated first, including children. Vaccine inequality is an unfair challenge the world is already facing and the WHO stands for completing the two-dose schedule globally before introducing booster doses. The rich nations have to ensure that poor nations do get their fair share of vaccines because this pandemic will not end till there is a global herd immunity which can be obtained only through universal immunisation. As long as this pandemic rages in any part of the world, there is always a threat of a more dangerous variant cropping up.

India has taken leadership in this regard by upscaling vaccine production not only to meet the needs of its own people but also to export to other countries. Global leaders and investors must be encouraged to step up participation in vaccine development.

As the COVID-19 pandemic panned out, it gave rise to a Covid ‘infodemic’ in the country with a lot of unverified information handed down to the common man. This leads to misinformation and is also instigating vaccine hesitancy. Such sensitive information should be provided only via responsible sources with caution to dispel myths.

We have to keep our surveillance at the highest level as a little bit of complacency may again put us in a spot of bother. Testing, tracing and genomic surveillance should be continued even when cases are at the lowest level in our country. No nation can afford to lower its guard as yet. In today’s world of swift transportation and globalisation, any infectious pandemic is just a flight away from your country!

The best remedy to the current catastrophe would be keeping patience, achieving community vaccination and observing COVID-19 appropriate social behaviour. We need to keep up the community spirit and attitude towards social vaccination (physical distancing, use of masks and hand hygiene) as it is beyond doubt the most effective barrier against any variant.

We need to re-emphasise to the community again and again that if we couple social vaccination with biological vaccination in our daily lives, we can safely co-exist with this virus.

Dr Aishwarya R is Resident, Infectious Diseases, and Dr Neeraj Nischal is Additional Professor, Department of Medicine, All India Institute of Medical Sciences, New Delhi. Views expressed are personal.

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