A coronavirus variant first identified in India has been designated as a “variant of concern” as small clusters of cases continue to be detected in some areas across England.

Experts from Public Health England (PHE) have been tracking B16172 (also known as VOC-21APR-02) – which is one of three related variants first seen in India and has since been detected in the UK.

The other two variants – dubbed B16171 and B16173 – remain classified as “variant under investigation”.

Why has B16172 been designated as a variant of concern?

Scientists believe this variant can spread more quickly than two other related variants seen in India.

It is thought to be at least as transmissible as the variant detected in Kent last year, known as B117, which is now dominant in the UK.

Dr Susan Hopkins, Covid-19 strategic response director at PHE, said: “We are monitoring all of these variants extremely closely and have taken the decision to classify this as a variant of concern because the indications are that this VOC-21APR-02 is a more transmissible variant.”

PHE said there is currently “insufficient evidence” to indicate that any of the variants recently detected in India cause more severe disease or make the vaccines available any less effective.

How many cases have been detected in the UK?

According to data by PHE released on Friday, there are, at present, 520 confirmed cases of the B16172 variant in the UK, from 202 over the last week.

The report also showed 261 cases of B16171 and nine cases of B16173.

The cases are spread across the country, with the majority in two areas – the North West, mainly in Bolton, and London.

PHE said around half of these cases are related to travel or contact with a traveller.

PHE health protection teams are working with local authorities, public health officials and NHS Test and Trace to detect cases and limit onward spread.

Surge testing is expected to be deployed where there is evidence of community transmission.

Is B16172 variant driving the second wave in India?

India reported 412,262 new Covid-19 cases and 3,980 Covid-19-related deaths on Thursday – both new single-day records.

In the past 30 days, the country has recorded 8.3 million cases.

However, it remains unclear whether the new coronavirus variants are driving the second wave.

Experts say large gatherings, and lack of preventive measures such as mask-wearing or social distancing, are playing a key role in the spread of the virus.

Although India has the world’s biggest vaccine making capacity, the country has partially or fully immunised less than 10% of its 1.35 billion people.

Will vaccines still work?

At present, there is no evidence the B16172 variant is resistant to current vaccines.

Although deemed to be more transmissible, it does not feature the E484K mutation found in the South African variant of the virus, which could help the virus evade a person’s immune system and may affect how well coronavirus vaccines work.

What other variants of concern have been identified in the UK?

All viruses undergo small genetic changes as they make copies of themselves in the host.

Most of these mutations are harmless but some can make the disease more infectious or threatening, and evade protection gained through infection or vaccination.

PHE has designated the UK (Kent), South Africa and Brazil variants as variants of concern.

Both the South Africa variant (B1351) and the Brazil variant (P1) have been detected in the UK.

Current vaccines have been designed for earlier versions of coronavirus, but scientists believe they should still work, but may be less effective.

But experts are confident existing vaccines can be tweaked to better tackle emerging mutations.

The UK Government has a deal with biopharmaceutical company CureVac to develop vaccines against future variants, and has pre-ordered 50 million doses.