There are two new coronavirus variants emerging in Brazil, with one causing more concern than the other.
One of the variants has led to the banning of all flights from South America to the UK, but it has not been detected in Ireland.
What do we know about the new variants?
Brazil variant causing concern
The Brazilian variant (P1) has three key mutations in the spike receptor binding domain (RBD) that largely mirror some of the mutations experts are worried about in the South African variant.
The coronavirus RBD is one of the main targets for our immune defences and also the region targeted by vaccines. Changes within this region are therefore worrisome.
Experts detected the new variant circulating in December in Manaus, north Brazil.
It is not yet known if the mutation causes more severe Covid-19, but evidence suggests it may be more transmissible.
British scientists are conducting more analysis to confirm evidence that indicates the strain does not cause any higher mortality rate or that it affects the vaccines or treatments.
It was detected in Brazil and in travellers from Brazil to Japan, and contains a unique constellation of lineage defining mutations.
Like the South African variant, the Brazilian one carries a mutation in the spike protein called E484K, which is not present in the UK strain.
The E484K mutation has been shown to reduce antibody recognition, helping the virus to bypass immune protection provided by prior infection or vaccination.
Scientists analysing the Brazilian variant say the mutations it shares with the South African variant seem to be associated with a rapid increase in cases in locations where previous attack rates are thought to be very high.
They say it is therefore essential to rapidly investigate whether there is an increased rate of re-infection in previously exposed individuals.
What about the other variant from Brazil?
This one has been detected in the UK, but experts say it is no cause for concern.
It has been reported to be spreading in the Rio de Janeiro State, and is associated with two independent reinfection cases in Brazil, according to the Covid-19 Genomics UK (Cog-UK) consortium.
While it also carries the E484K mutation, it is not currently considered sufficient to designate it as a “Variant of Concern”.
This variant (P2) does not contain the other important mutations carried by the more concerning variant (P1).
Will vaccines still be effective against the new variants?
Vaccines are still likely to be effective as a control measure if coverage rates are high and transmission is limited as far as possible.
Although early indications are that vaccines will work, experts say it is still too early to be sure if they will be effective against the Brazilian and South African variants, while it is thought they will work against the UK variant.
Nevertheless scientists believe a new coronavirus jab could be manufactured within just 30 to 40 days if a variant of the virus is found to be less responsive to the vaccines available.
Experts say the new vaccines are essentially like emails that we send to the immune system, and are very easy to tweak.
If the virus has changed, that email simply has to be edited, with a word or two changed, and in a number of weeks a new vaccine will be ready that can better target the new strain.
Why do viruses mutate?
There have been many mutations in Sars-CoV-2, the virus that causes Covid-19, since it emerged in 2019, some more significant than others.
However, this is to be expected as this virus is an RNA virus, like the flu and measles, and these tend to mutate and change.
Mutations usually occur by chance, and the pressure on the virus to evolve is increased by the fact that so many millions of people have now been infected.
Sometimes mutations can lead to weaker versions of a virus, and it could even be that the changes are so small they have little impact on how it behaves.
However, the new UK variant spreading in Ireland is more transmissible, and it is thought the same may be true of the Brazilian variant.
Viruses evolve in order to survive – mutations are a simple mistake that give the virus a chance to keep infecting people.
What is a mutation?
In simple terms, a virus delivers a set of instructions into a cell in the body and the cell follows these instructions to make more new virus.
The instructions are replicated, so that each new virus that is created gets a single copy of the copied code.
Sometimes there is a mistake in the instructions, and when this virus infects a new cell it will either fail, or the virus will continue to replicate the mutated code.
