Coronavirus: why new strains are 'really bad news' for controlling Covid-19

Scientists say new, more infectious strain will probably dominate other coronavirus variations worldwide

Pasqualina Ghilardi, 87, centre, is flanked by carer Michela Valle, left, and director Maria Giulia Madaschi, as she talks on a video call with Caterina Damiano, a donor unrelated to her, who bought and sent her a sweater as Christmas present through an organisation dubbed "Santa's Grandchildren", at the Mariano Zanchi nursing home in Alzano Lombardo, one of the area that most suffered the first wave of Covid-19, in northern Italy. AP Photo

A masked security guard stands to watch in front of a coronavirus-themed Christmas tree decorated with masks and rubber gloves in Hanoi, Vietnam. AP Photo

A glass wall is decorated with the name of a Christmas song, "Let it snow," as registered nurse Ashley Gould checks on a patient in an intensive care unit at Providence Holy Cross Medical Centre in the Mission Hills section of Los Angeles. AP Photo

A demonstrator takes part in a protest asking for the vaccine for the coronavirus and against Brazilian President Jair Bolsonaro, in Brasilia, Brazil. Reuters

Clinicians care for a patient in the Intensive Care Unit (ICU) at Providence St Mary Medical Centre amid a surge in Covid-19 patients in Southern California. AFP

A couple stands at Rome's Termini train station one day before Italy goes back to a complete lockdown for Christmas as part of efforts put in place to curb the spread of the coronavirus disease (COVID-19), in Rome, Italy.. Reuters

Registered nurse Dania Lima, right, helps fellow nurse Adriana Volynsky put on her personal protective equipment in a Covid-19 unit at Providence Holy Cross Medical Centre in the Mission Hills section of Los Angeles. AP Photo

Dr Mher Onanyan takes a short break while waiting for an X-ray of a Covid-19 patient's lungs at Providence Holy Cross Medical Centre in the Mission Hills section of Los Angeles. AP Photo

Patient Efrain Molina, centre, gets a fist bump from nurse leader Edgar Ramirez at Providence Holy Cross Medical Centre in the Mission Hills section of Los Angeles. AP Photo

A boy stands near a Christmas tree with a coronavirus-themed decoration in Bali, Indonesia. AP Photo

With coronavirus inoculation programmes launching the world over, hopes began to rise that the end of the pandemic could be in sight.

But the emergence of new, more infectious variants and a surge in cases made it clear that the global fight against Covid-19 is far from won.

One strain, first identified in the UK (known as VUI 202012/01) is been blamed for a heavy increase in cases in London and other parts of England. A similar but separate variant found in South Africa (known as 501Y.V2) is also thought to be causing infections there to dramatically rise.

So what are these new strains and what problems could they cause? The National explains.

What is different about the new strains?

The strain first detected in the UK was traced to samples collected in London and south-east England in September. It has 23 mutations in its genetic material, 17 of which affect the virus’s proteins, and eight of these affect the spike protein – which the virus uses to attach to human cells.

Such mutations arise randomly as the virus replicates its RNA genetic material, but ones that confer a benefit to the virus are likely to become more common.

One spike protein mutation, N501Y, may make it easier for the virus to bind to and infect human cells, where it reproduces.

Other mutations in the UK variant are linked to increased infectiousness.

The South African variant has the same N501Y mutation, but researchers concluded that it arose independently.

Why are the new strains a problem?

Because of the mutations they contain, especially those that enable them to infect cells more easily, the new variants spread faster between people.

The UK form spreads as much as 70 per cent more easily, but is not thought to make people more ill.

But there are concerns that the South African variant might cause more illness among younger people, because the country has recorded an increase in severe cases among younger, otherwise healthy people.

How widely are they likely to spread?

The UK variant is becoming increasingly common there and has also been found in Australia, Belgium, Denmark, France, Gibraltar, Hong Kong, Italy and the Netherlands, while the South African form has been detected in the UK. It may be more widely distributed, because only a small proportion of coronavirus samples have their genetic material sequenced.

Prof Paul Hunter, an infectious diseases specialist at the University of East Anglia in the UK, said they would probably become the dominant strains globally, mirroring what happened with a variant, D614G, that appeared early this year and is characterised by a particular spike protein mutation.

“[D614G spread] quite rapidly and came to dominate the variants globally. Almost certainly one or the other of these new variants will do that,” he said.

What will the variants mean for infection rates?

Prof Hunter described the new variants as “really bad news” for controlling the pandemic. Work he and his colleagues have done, but not published yet, suggests that during England’s national lockdown in November, the reproduction number (R) – the number of people an infected individual spreads the virus to – fell to about 0.7 at best. But the new UK variant adds at least 0.4 to R. So even measures such as the closure of non-essential shops, restaurants, cinemas and gyms, may not keep R below 1 and stop infections from increasing.

“We know that because it [the new UK variant] was growing during the lockdown,” Prof Hunter said. “Every other variant was in retreat except for this one. It does mean it’s going to be really difficult.”

Read more: What is an 'R rate' and what does it mean when it falls below 1?

Where did the new forms arise?

Although one strain is linked to the UK and the other to South Africa, researchers cannot say for certain that these countries are where they evolved.

The UK has done as much genetic sequencing of coronavirus samples as the rest of the world put together, so is more likely than other nations to detect new variants wherever they arose.

Similarly, it is possible the strain first detected in South Africa evolved outside the country.

Will vaccines still work?

The coronavirus vaccines cause people to produce antibodies that recognise numerous sites on the spike protein, so a single change is unlikely to have much effect on their effectiveness. However, researchers are carrying out laboratory analysis to confirm this.

Scientists may have to produce new vaccines in future in response to further evolution of the coronavirus, such as for seasonal influenza. But, for the moment, this is not thought to be necessary.

The vaccines based on messenger RNA, a type of genetic material, such as the Pfizer-BioNTech vaccine used in Dubai, and the Moderna vaccine, could be tweaked particularly easily.