Where’s next for Tier Four?

By David Churchill

What has happened to the coronavirus to trigger such concern?

A new strain of Covid has developed which is said to spread far faster. A ‘strain’ is a new version of a virus which has genetic mutations. The new strain is a version of Sars-Cov-2, the coronavirus which causes the disease Covid-19.

It has been named VUI-202012/01. These letters and numbers stand for ‘variant under investigation’ and the month, December 2020.

What makes it so worrying?

This particular variant is defined by up to 17 changes or mutations in the coronavirus spike protein. It is the combination of some of these changes which scientists believe could make it more infectious.

It is thought they could help the virus’ spike protein latch on to human cells and gain entry more easily.

Is it certain the new variation is accelerating the spread of the virus?

No, but scientists say preliminary evidence suggests it does.

Boris Johnson said it may spread up to 70 per cent more easily than other strains of the virus, potentially driving up the ‘R rate’ – which measures how quickly the virus spreads – significantly.

On Saturday night, Mr Johnson said it could drive up the ‘R rate’ by as much as 0.4.

This would be particularly significant in areas such as Eastern England, where it is 1.4, and both London and the South East, where it is 1.3. The ‘R rate’ must remain below 1 for infections to decrease.

Is the new variant more dangerous?

Scientists don’t think so for now. When asked on Saturday night if it was more lethal than the previous strain, Chief Medical Officer Professor Chris Whitty said ‘the answer seems to be ‘No’, as far as we can tell at the moment’.

Yesterday Dr Susan Hopkins, of Public Health England, said there was evidence of people with the new variant having higher viral loads inside them.

But she said this did not mean people would get more ill.

Ravi Gupta, professor of clinical microbiology at the University of Cambridge, said: ‘It’s unlikely it’ll make people sicker, but it could make it harder to control.’

If it does make the virus harder to control and hospitals become overrun, it could pose new challenges.

Are mutations unusual?

No. Seasonal influenza mutates every year. Variants of Sars-Cov-2 have also been observed in other countries, such as Spain.

However, one scientific paper suggests the number and combination of changes which have occurred in this new variant is potentially ‘unprecedented’.

Most mutations observed to date are thought to have happened more slowly. Also, most changes have no effect on how easily the virus spreads.

There are already about 4,000 mutations in the spike protein gene.

What has caused the mutation?

This is still being investigated. One theory is that growing natural immunity in the UK population, which makes it harder for the virus to spread, might have forced it to adapt.

Another theory is that it has developed in chronically ill patients who have fought the virus off over a long period of time, with it then being passed onto others.

Prof Paul Hunter, Professor in Medicine at the University of East Anglia, yesterday said it was ‘plausible’ and ‘highly likely’ this has happened.

However, he stressed it is impossible to prove at the moment.

What evidence is there to support the latter theory?

Some evidence supporting it was spotted when samples of virus were collected from a Cambridge patient. They had been treated with convalescent plasma – blood plasma containing antibodies from a recovered patient.

It is possible the virus mutated during that treatment, developing more resistance to the antibodies. This patient died of the infection, but it’s also possible the mutation has occurred elsewhere.

A paper co-authored by Andrew Rambaut, Professor of Molecular Evolution at the University of Edinburgh, states: ‘If antibody therapy is administered after many weeks of chronic infection, the virus population may be unusually large and genetically diverse…creating suitable circumstances for the rapid fixation of multiple virus genetic changes.’

Professor Hunter added: ‘Mutation in viruses are a random event and the longer someone is infected the more likely a random event is to occur.’

What do these mutations do?

Many occur in what’s called the ‘receptor binding domain’ of the virus’ spike protein. This helps the virus latch on to human cells and gain entry. The mutations make it easier for the virus to bind to human cells’ ACE2 receptors.

It is also possible the changes help the virus avoid human antibodies which would otherwise help fight off infection.

Who detected it?

It was discovered by the Covid-19 Genomics UK (COG-UK) consortium, which carries out random genetic sequencing of positive covid-19 samples.

It is a consortium of the UK’s four public health agencies, Wellcome Sanger Institute and 12 academic institutions.

How long has it been in the UK and where did it start?

As of mid-December, there were more than 1,000 cases in nearly 60 different local authorities, although the true number will be higher.

They have predominantly been found in the south east of England, in Kent and London. It may now account for 60 per cent of the capital’s cases.

But it has been detected elsewhere, including in Wales and Scotland.

The two earliest samples were collected on September 20 in Kent and another the next day in London.

Why was action to tackle it not taken sooner?

Because the potentially greater transmissibility was only discovered late last week by academics.

Has it been detected anywhere else in the world?

One aspect of the new variant, known as a N501Y mutation, was circulating in Australia between June and July, in America in July and in Brazil as far back as April, according to scientists.

It is therefore unclear what role, if any, travellers carrying the virus may have had.

Dr Julian Tang, a Virologist and expert in Respiratory science at the University of Leicester, said: ‘Whether or not these viruses were brought to the UK and Europe later by travellers or arose spontaneously in multiple locations around the world – in response to human host immune selection pressures – requires further investigation.’

Another change, known as the D614G variant, has previously been detected in western Europe and North America. But it is possible that the new variant evolved in the UK.

What can I do to avoid getting the new variant?

The same as always – keeping your distance from people, washing your hands regularly, wearing a mask and abiding by the tier restrictions in your area.

Yesterday Dr Chaand Nagpaul, chair of the British Medical Association, said: ‘The way in which you control the spread of the virus, including this new variant, is exactly the same. It is about continuing stringent measures. The same rules apply.’

Will the new variant reduce the effectiveness of vaccines?

More studies are needed.

Dr Susan Hopkins, of Public Health England, said that until these are carried out scientists cannot be certain whether – and by how much – the new variant reduces the effectiveness of developed vaccines.

She said: ‘The vaccine induces a strong, multiple response, immune response and therefore it is unlikely that this vaccine response is going to be completely gone.’ When mutations happen it is, in theory, possible the antibodies generated by vaccines can be evaded.

But vaccines produce a wide range of antibodies that simultaneously attack the virus from different angles, making it hard for it to evade all of them at once.

Vaccines could also be tweaked to make them more effective if the new mutation does prove to be more resistant to them.

So what are the scientists doing now?

Scientists will be growing the new strain in the lab to see how it responds. This includes looking at whether it produces the same antibody response, how it reacts to the vaccine, and modelling the new strain.

It could take up to two weeks for this process to be complete.