New, evolving coronavirus variants that are potentially more infectious and may be resistant to Covid-19 vaccines are raising concerns about the ability to fight the virus.

Why is the coronavirus mutating and why are there variants?

All viruses evolve and mutate as they make copies of themselves to spread and survive. This coronavirus is no different. It has developed into many thousands of different versions, or variants, circulating around the globe.

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Which is the main one in Ireland?

The dominant one, accounting for more than 90 per cent of infections in Ireland, is the UK or Kent variant, known as B117, that was detected in the southeast of England in the autumn.

This is up to 70 per cent more transmissible than the original strain that started the pandemic and is one reason why the third wave in Ireland since Christmas has been so severe as it has shown to infect more close contacts than earlier strains.

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Have other variants been detected here before this week?

Yes. Fifteen cases of the South African variant “B1351” have been detected in Ireland. The concern is that this variant can spread more readily.

Three cases of a Brazilian variant P1 were detected in the State last week.

Like the South African variant, the Brazilian strain carries a mutation in the spike protein – the part of the virus that allows it to infect a host – called E484K, which is not present in the UK strain but which helps bypass immunity from past infection.

In other words, if you had Covid-19 previously caused by the original or earlier variant, you could become reinfected with this strain.

What other strains have been detected this week?

One case of the B1525 variant, known as the Nigerian variant, has been found in Ireland. It was identified through contact tracing and connected to travel.

This has also been detected in the UK, Denmark and the US and, worryingly, has significant mutations already identified in other variants.

This strain has the E484K mutation as well as other properties that make it similar to the UK variant. The Nigerian strain also has a deletion in the spike protein that increases transmissibility.

Will the vaccines being administered here work against these variants?

Scientists say it is still too early to say whether the current vaccines, developed to fight the original coronavirus strain, will be as effective against the new Brazilian, South African and Nigerian strains, but they are working against the UK variant. The concern is that the virus is evolving in a way that could enable it to spread more easily and withstand the vaccines.

Are there other strains we should be watching out for?

Yes. A strain first detected in California in July – known as B1427/B1429 but also sometimes referred to as 20C/L452R – has spread rapidly there and has been found to be more dangerous.

It has three mutations in the crucial spike protein, one of which allows the virus attach more firmly to its host – an adaptation not been seen in other coronavirus variants. It has been found to be more resistant to neutralising antibodies triggered by vaccines and previous infections.