So what do we know about the two-dose vaccine?
The Moderna vaccine is "highly effective" in preventing symptomatic and asymptomatic infections in “real-world conditions”, according to a study shared by the US Centers for Disease Control and Prevention (CDC).
In the study, researchers examined nearly 4,000 at-risk essential workers, such as healthcare workers and first responders, who received the vaccine across six American states from 14 December to 13 March, 2021.
Results showed that a two-dose regimen of the Moderna vaccine prevented 90 per cent of infections two weeks after people received the second dose.
The jab also prevented 80 per cent of infections two weeks after people received the first dose, the study added.
The findings were consistent with the results from the clinical trials conducted by Moderna.
How many doses has the UK ordered?
The government has bought 17 million doses - enough to vaccinate about 8.5 million people.
The UK rollout
A 28-year-old solicitor has become one of the first people in England to receive the Moderna vaccine as part of the mass vaccination programme. Emily Sanderson received the jab at the Sheffield Arena vaccination centre.
Ms Sanderson, who has an underlying health condition, was due to receive the AstraZeneca vaccine but it was changed to Moderna, the NHS said.
It comes after UK regulators said that people under the age of 30 should be offered an alternative to the AstraZeneca vaccine, saying there was a possible link between the jab and "extremely rare" blood clots.
The vaccine was first distributed in Wales last week.
How much does the vaccine cost?
It is one of the most expensive vaccines developed so far. The UK is believed to have spent between £24 and £28 per dose on the jab.
The vaccine’s development was partly subsidised by the US government and will cost the US about $15 (£10.86) a dose, while the EU is paying $18 (£13.03), according to the BMJ.
Israel is paying “$23.50 per dose on average” as part of a deal that saw the country “obtain early shipments”, the journal adds.
How does the vaccine work?
It introduces a genetic sequence – messenger ribonucleic acid (mRNA) – in to the body, which instructs cells to produce the Sars-CoV-2 spike protein, known as an “antigen”.
The immune system then springs into action to fight off what it perceives to be a foreign invader. The process leaves behind a protective memory that enables the body to tackle the real infection.
No actual virus is needed to create an mRNA vaccine. This makes it easier to both develop the vaccine and then manufacture it on a larger scale than traditional jabs.
Production and storage
Most of the vaccine developed by Moderna, a US biotech company, is produced at its base in Cambridge, Massachusetts.
One of its manufacturing partners, Lonza, is helping Moderna supply doses to Europe.
Recipharm's drug manufacturing site in France is also undertaking fill and finish services for countries outside of the US.
The vaccine can maintain its integrity for up to 30 days in household fridges, at room temperature for up to 12 hours, and remains stable at -20C for up to six months.
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