Covid-19 variants in the UK: What strains are of concern and under investigation?

Prime Minister Boris Johnson cancelled his trip to India next week amid concern over the country's rising coronavirus cases and its Covid-19 variant, which is also present in the UK.

Only a few hours later on Apr 19, Matt Hancock confirmed that India had been added to the "red list" for international travel. It comes after 103 cases of the Indian variant have been identified in the UK, of which the "vast majority have links to international travel".

Viruses constantly change through mutation, and the emergence of new variants of coronavirus is a natural part of this process.

Some variants will emerge and then disappear, while others persist and can have worrying mutations.

Each variant that enters the UK will be assessed by experts, and if considered to be potentially dangerous will become a variant under investigation (VUI).

This may then be upgraded to a variant of concern (VOC) if the potential danger is deemed to be sufficient.

What is the difference?

All Covid variants, if considered to have concerning epidemiological, immunological or pathogenic properties, are raised for formal investigation.

At this point they are designated Variant Under Investigation ( VUI ) with a year, month, and number.

Following a risk assessment with the relevant expert committee, they may be designated Variant of Concern ( VOC ).

Scientists are particularly concerned about variants of coronavirus that have key changes in the spike protein of the virus.

Mutations in a specific region of the spike protein may allow the virus to evade or partially evade the effectiveness of vaccines or natural immunity. One mutation of particular concern in this area is called E484K.

Variants of concern with the E484K mutation seem to spread more easily and more quickly than other variants, which may lead to more cases of Covid-19 and, subsequently, more death.

Some variants may also cause more severe disease.

Which ones are in the UK?

To date, Public Health England (PHE) has seven variants under investigation (VUI), including the one from India, of which 77 cases have been identified in the UK.

A VUI is a variant that is being closely examined by experts to see whether it is more deadly, can transmit more easily or may evade vaccines.

If it meets any of these criteria, it moves from being under investigation to become a variant of concern (VOC).

There are currently four variants of concern in the UK. These are the variant first found in Kent, the Kent variant with a specific E484K mutation, the Brazilian variant (carries E484K) and the South African variant (carries E484K).

Here is when they entered the UK.

Dr Susan Hopkins, chief medical adviser for NHS Test and Trace, said at the weekend: "We have seen a couple of cases (of the Indian variant) that haven't arisen from travel but we're still trying to undergo the investigations to look in great detail at where they might have acquired it from.

"To escalate it up the ranking we need to know that it has increased transmissibility, increased severity or vaccine evading, and we just don't have that yet."

The UK's seven variants under investigation

1. B.1.617 | Indian variant - 103 known cases

2. P.3 | Variant of unknown origin - 5 known cases

3. B1.324.1 with E484K | Variant of unknown origin - 2 known cases

4. B1.1.318 | Variant of unknown origin - 113 known cases

5. B.1.525 (previously designated UK1188) | English variant - 361 known cases

6. A.23.1 with E484K | English variant - 79 known cases

7. P.2 | Brazilian variant - 59 known cases

The UK's four variants of concern

1. B.1.1.7 with E484K | English variant - 43 known cases

2. P.1 | Manaus, Brazil/Japanese variant - 40 known cases

3. 501Y.V2 B.1.351 | South African variant - 600 known cases

4. B.1.1.7 | English variant - 209,492 known cases

Do vaccines work against variants?

The picture is currently unclear, although most experts say the current range of vaccines in use should offer some protection against variants.

Studies are ongoing and Public Health England (PHE) is expected to say more about vaccine effectiveness against variants in the future.

Pfizer has published research suggesting its jab could offer good protection against the Brazilian and South African variants, and early results from Moderna suggest its vaccine has some effectiveness against variants.

AstraZeneca has also said it hopes its vaccine will protect against severe disease from any variant.

According to the World Health Organisation (WHO), all Covid-19 vaccines elicit a broad immune response involving a range of antibodies and cells.

Therefore, changes or mutations in the virus should not make vaccines completely ineffective.

If vaccines are found to have very little effect, then new vaccines can be created to protect against variants. Most of the firms that produced initial vaccines are already working on a new range of jabs.

Here is how the vaccine rollout in the UK is progressing.

Are scientists worried about the situation in India?

Some are, yes, and after calls for India to be put on the "red list" for travel, this was confirmed by Matt Hancock on Apr 19.

The addition of India to the red list means anyone without British residency rights will be refused entry to the UK, while all UK and Irish residents and British citizens who have been in India in the past 10 days will have to hotel quarantine on arrival in the UK at a cost of up to £1,750 per person.

Danny Altmann, professor of immunology at Imperial College London, said the variant of coronavirus first identified in India is likely to become a variant of concern.

However, Dr Jeffrey Barrett, director of the Covid-19 Genomics Initiative at the Wellcome Sanger Institute, said that while the variant should be watched carefully, it is "probably not at the top tier of mutations that generate the most concern".

He said it was not yet known whether the variant was driving the current wave of infections seen in India.

Professor Andrew Hayward, who is on the Scientific Advisory Group for Emergencies (Sage), said the "evidence of increased transmissibility and escape from immunity is circumstantial" for the Indian variant.

But said he would "err on the side of caution" and "act sooner rather than later" when it comes to imposing increased travel restrictions.