How does it work?
Like the Pfizer/BioNTech shot, the Moderna vaccine uses a new technology called mRNA that introduces genetic material containing the instructions to make the coronavirus’s spike protein into the body to elicit an immune response. Traditional vaccine approaches typically kickstart the immune system by exposing it to a killed or weakened part of the virus.
How effective is it?
In line with the Pfizer/BioNTech data, final results of Moderna’s vaccine against Covid-19 confirmed it has 94% efficacy and nobody vaccinated in the 30,000-participant trial developed severe disease.
In the US clinical trial half the participants were given the jab, while the remainder got the placebo — overall, 196 people fell ill. Thirty experienced severe disease and one person died — but none of these people got the Moderna shot.
How does it fare against other authorised vaccines?
In the clinical trial setting, all three vaccines authorised in the UK were 100% effective in preventing hospitalisations and death.
The two mRNA vaccines are relatively similar in terms of preventing Covid-19. The Pfizer shot secured a similarly staggering 95% efficacy. In a pooled analysis of trials in the UK and Brazil, the Oxford/AstraZeneca vaccine showed 70% efficacy overall, while in a US trial, the vaccine demonstrated 76% efficacy.
However, that lower efficacy is arguably offset by its storage advantage – the Oxford jab can be kept at normal fridge temperatures, making it particularly useful in places that are not kitted up with the onerous ultra-cold freezers operating at -70C to -80C that are necessary for the Pfizer vaccine.
Moderna’s vaccine is relatively easy to store: it is stable for 30 days at normal fridge temperatures, but should it need to be stored for longer it can last for six months at -20C. Cost is another differentiator — last year Moderna said it was charging $32 (£24) to $37 a dose and defended its right to make a profit. The Oxford vaccine is not for profit, and is priced at £3 ($4) a dose.
Is it a game-changer for the UK?
The UK has ordered more than 400m doses of seven different vaccines — including 100m from AstraZeneca, 40m from Pfizer, and 17m from Moderna. Given vaccine supply hiccups have already occurred and more will likely crop up — any additional shots are beneficial. “Any vaccine supply that we have to achieve our target of vaccinating all adults is to be welcomed,” said Paul Hunter, a professor in medicine at the University of East Anglia.