THE Moderna coronavirus vaccine is the third jab to be rolled out in the UK.

It will be administered to people in Wales from Wednesday, with patients in Carmarthenshire becoming the first in the UK to receive it.

It follows the rollout of the Pfizer and AstraZeneca vaccines, which began in December and January respectively.

Here is everything we know about the Moderna vaccine.

How effective is it against coronavirus?

The phase three results suggested vaccine efficacy against the disease was 94.1%, and vaccine efficacy against severe Covid-19 was 100%.

More than 30,000 people in the US took part in the trial, from a wide range of age groups and ethnic backgrounds.

Two doses were given 28 days apart so researchers could evaluate safety and any reaction to the vaccine.

The analysis was based on 196 cases, of which 185 cases of Covid-19 were observed in the placebo group versus 11 cases observed in the active vaccine group.

Moderna also released data relating to severe cases.

All 30 severe cases occurred in the placebo group and none in the group which had received the vaccine, known as mRNA-1273.

How many doses of Moderna does the UK have?

The Government has bought 17 million doses – enough to vaccinate about 8.5 million people.

How does the vaccine work?

The Moderna jab is a messenger RNA (mRNA) vaccine.

Conventional vaccines are produced using weakened forms of the virus, but mRNAs use only the virus’s genetic code.

An mRNA vaccine is injected into the body, where it enters cells and tells them to create antigens.

These antigens are recognised by the immune system and prepare it to fight coronavirus.

No actual virus is needed to create an mRNA vaccine.

This means the rate at which the vaccine can be produced is accelerated.

Is the vaccine safe?

Moderna said the vaccine was generally well tolerated, with no serious safety concerns identified.

Severe events after the first dose included injection-site pain, and after the second dose included fatigue, myalgia (muscle pain), arthralgia (joint pain), headache, other pain and redness at the injection site.

But these were generally shortlived.

Is the Moderna vaccine effective against variants?

In late January, the company behind the vaccine said it was effective against both the strain first detected in south east England and the mutation which first emerged in South Africa.

Moderna said laboratory tests found no significant impact on antibodies against the UK variant relative to prior variants.

While there was a six-fold reduction in neutralising antibodies produced against the South African variant, the levels remained above those that are expected to be protective, Moderna said.

What stage is the Moderna rollout at in each of the four UK nations?

People in Wales will get first doses of the vaccine from Wednesday, at the West Wales General Hospital in Carmarthen.

The rollout will begin in England “as soon as possible this month”, a Department of Health and Social Care spokesperson said.

Scotland’s First Minister Nicola Sturgeon said the first batch of Moderna vaccines had arrived in the country on Monday and will be delivered over the coming months.

It has not been confirmed when the rollout of Moderna will begin in Northern Ireland.

Health Minister Vaughan Gething said: “This is another key milestone in our fight against the Covid-19 pandemic. A third vaccine for use in Wales significantly adds to our defences in the face of coronavirus and will help to protect our most vulnerable.

“Every vaccine given to someone in Wales is a small victory against the virus and we would encourage everyone to go for their vaccine when invited.

“If people cannot attend their appointment we ask them to let the health board know via the contact details provided in their invitation as this vaccination slot can be offered to someone else rather than be wasted.

“Once you have been vaccinated, you should continue to follow guidance, staying two metres apart, washing your hands and wearing a face covering to protect those around you.

“I want to thank all those who have been working tirelessly to deliver the vaccine across Wales and help us meet our second milestone of offering a vaccine to all phase one priority groups.

"I also want to thank the 1.5 million people in Wales that have already come forward for their vaccine and done their bit in this national effort.”