Omicron, Delta, Alpha: How the UK became an early flag for dangerous Covid-19 variants

By Lucia Stein for ABC

Throughout the pandemic, the United Kingdom has, at times, been an early indicator to other countries of the dangers posed by new variants.

It is where the Alpha variant was first discovered, causing more than 50,000 deaths on either side of its peak in mid-January 2021 and changing the course of the pandemic.

Then the UK's battle with the highly infectious Delta strain became an early sign of how that variant would rapidly spread through other countries.

Now Omicron is swiftly moving through Britain, with cases already surpassing the UK's peak pandemic levels and setting new records.

On Friday another new infection record was set with a further 93,045 people testing positive, bringing the weekly total to 477,229 - a 38.6 percent increase on the previous seven days.

In England, cases are rising faster in London than other regions. And scientists are taking note.

"But … between different countries - infections, fatality rates, underlying health conditions, the health status of the population in general - these are all things which influence the progression and the severity of the [virus]."

So how is it that the UK came to be a red zone for Covid-19 variants to spread? There are a few explanations.

An early success story

After a successful vaccination drive earlier this year, things were looking positive in the UK.

Scientists tracking the epidemic found increasingly strong evidence that the program was breaking the link between Covid-19 cases and deaths.

It seemed as if the UK had a window of opportunity to bring the virus under control. But then it opened up.

England became one of the first regions in Western Europe to lift almost all of its Covid-19 restrictions on 19 July.

Freedom Day marked the end of mask-wearing and social distancing requirements. Shops, museums, theme parks, bars, nightclubs and pubs all opened.

But leading scientists and government advisors from all over the world expressed their doubts.

More than 1200 scientists supported a letter to the Lancet medical journal, calling the plans "dangerous and premature".

At a virtual summit at the time, Professor Christina Pagel warned that there was potential for a new variant of Covid-19 to emerge.

"Any mutation that can infect vaccinated people better has a big selection advantage and can spread," the director of the Clinical Operational Research Unit at University College London warned.

Months later, Omicron arrived on the UK's doorstop.

A gateway to the world

Being an island has been a clear advantage for other countries during the pandemic, but the UK has proved an exception. One factor above all helps explain why.

"It's a global [travel] hub and there's lots of people that fly in and out," Clarke, told the ABC.

"We're also very reliant on imports and exports from continental Europe. So we may be an island, but we're a bit of a hub globally. There are always lots of people coming into the country or just passing through."

While its status as a global travel hub goes some way to explaining the UK's previous experience with Covid-19 variants, scientists have offered other explanations.

One factor could be waning immunity from the earlier primary shots of vaccines, according to Vinod Balasubramaniam, a virologist at Monash University in Malaysia.

A professorial fellow in epidemiology at The University of Melbourne, Professor Tony Blakely, agrees, theorising that the UK's current experience of Omicron may be because its population had AstraZeneca as the primary vaccination course.

"It is highly probable that what [the UK is] experiencing now [with Omicron] will be a forerunner of what happens in other countries," he told the ABC.

"Especially countries that have also used AstraZeneca, as [it's] less effective than the mRNA vaccines at preventing infection with Omicron."

A study by the University of Edinburgh, however, found that two doses of either Pfizer or the AstraZeneca vaccines were still 90 percent and 91 percent effective at preventing death from the Delta variant.

And analysis from health insurer Discovery Health in South Africa suggest that while the Pfizer vaccine is less effective in preventing Omicron infection, it still offers 70 percent protection against hospitalisation.

With the UK heading into winter, scientists say other elements are also contributing to rising Omicron cases.

Danger lurks in indoor gatherings

As temperatures plunge across the UK, more people are gathering indoors, providing the perfect breeding ground for Covid-19 to spread undetected.

"People moving inside will give the virus a greater opportunity to spread than [outside]," Clarke said.

"There's less exposure to sunlight and ultraviolet rays in the UK … So these are all things the virus likes, that allows it to spread more and to survive on surfaces and hang in the air."

That was how the Alpha variant rapidly made its way through England last year and then Delta.

And, with the UK having moved to a model of individual responsibility when it comes to public health measures, it is very possible variants have been able to spread due to people not complying with proper masking, social distancing or proper hand hygiene.

"Some of the spread could originate from human behaviours, for instance more groups gathering under loosened restrictions," Balasubramaniam told the ABC.

"We must remember that the UK is one of the earliest countries in the world in starting its vaccination campaign, so it may have provided a false sense of security to relax strict public health measures, especially in social gatherings in public places."

Together, this has created the perfect environment for Omicron to flourish.

"We are seeing the overall effects of removing restrictions earlier [and a] combination of improper compliance towards public health measures, waning immunity of vaccines and vaccine inequity contributing to rise in variant-specific spikes in cases," Balasubramaniam said.

From a few unsuspecting overseas travellers, Omicron has now spread rapidly throughout the UK, foreshadowing the experiences of other countries in the months ahead.

Two epidemics at once

Professor Chris Whitty has described the current situation in the UK as two epidemics in one.

Along with the Omicron variant rising rapidly throughout England, the country also continues to grapple with the older Delta variant, which is still causing a large number of infections.

Now the UK is in a race against both variants, with the government pinning its hopes on innoculating all eligible adults with a third dose by the end of the month.

"The virus is coursing through society and infecting an awful lot of people, and we're trying to keep up with that by jabbing lots of people," Clarke said.

"But the protection they get is always going to be a week or so behind the numbers of vaccinations."

Mask mandates in some indoor venues and Covid-19 passports have also been reintroduced, while people have been asked to work from home where possible.

The measures are considered to be at the very lighter end of what might be expected, given the UK's current situation, according to Clarke.

England was in lockdown when it hit a record number of Covid-19 cases in January. In comparison, the UK currently remains mostly open.

"I do wonder how much [the restrictions have] been introduced to prepare people for what might be due to come, rather than just hitting people with more onerous restrictions all in one go," Clarke said.

Even if more restrictions are to follow, experts say there are lessons to be learned from the UK's early experience with Omicron.

"We should not forget that already we have the 'weapons' - masks, social distancing - to reduce the risk of becoming infected," Balasubramaniam said.

"It should, therefore, be our main goal to slow down virus spread by adhering to the existing hygiene and speeding up the vaccination process, which now has to include booster doses at all age groups."

- ABC