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Moderna vs Pfizer vs Oxford: How do the COVID-19 vaccine candidates compare?

Written by on 16/11/2020

Three trials of vaccines that will be available to the UK have all reported they are around 90% effective in late stage trials.

Pfizer/BioNTech was the first to announce its results, followed a week later by Moderna which is still in trials.

The University of Oxford/AstraZeneca vaccine announced its phase three results a week after that on 23 November.

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How do the three vaccine candidates compare?

Both the Pfizer and Moderna jabs use technology known as mRNA, which introduces into the body a messenger sequence that contains the genetic instructions for the vaccinated person’s own cells to produce the antigens and generate an immune response.

mRNA technology has not been used before in vaccines, which brings both solutions and problems.

The Oxford vaccine works like a traditional inoculation where a spike protein of the virus is injected which the immune system builds up a response to if the real virus enters the body.

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All of them require two doses, with Pfizer’s three weeks apart, and Moderna and Oxford’s four weeks apart.


Final data from the Pfizer vaccine found it offers 95% protection against the virus within 28 days of the first dose.

It also proved 94% effective among adults over the age of 65 – who are generally more vulnerable.

Moderna’s results indicate 94.5% effectiveness but it said the trials are ongoing and the final number could change.

The Oxford trial found with two doses its vaccine was 62% effective, but when people were given a half dose followed by a full dose at least a month later its efficacy rose to 90%.

Pfizer vaccine
Image: The Pfizer vaccine has shown to provide around 90% protection against COVID

Transport and storage

One of the main differences between the candidates is how they need to be stored. The Moderna vaccine is much easier to distribute than the Pfizer jab, around which there are concerns – but the Oxford one is the easiest of them all.

During shipment and storage, the Pfizer vaccine must be kept at around -70C (-100F) to maintain optimal efficacy and it also has to be mixed with another liquid before it can be administered.

Pfizer has developed its own packaging to keep doses cold with dry ice so they can be stored for 10 days without specialised freezers, but doses would still have to be flown from Belgium then sent to vaccination centres in trucks with thermo sensors and GPS trackers.

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The Moderna vaccine has been shown to last for up to 30 days in household fridges, at room temperature for up to 12 hours, and remains stable at -20C – equal to most household or medical freezers – for up to six months.

The company claims mRNA-1273 can be distributed using widely available vaccine delivery and storage infrastructure – with no dilution required prior to vaccination.

Like most other vaccines, the Oxford one will need to be sent to vaccination centres in refrigerated vans or cool boxes and stored in a special vaccine fridge between 2C to 8C and protected from light.


Each of the three vaccines’ price tags varies widely, although this will be paid for by the government so will be free for those using the NHS.

The Moderna vaccine is very expensive. It was pitched for $38 (£28) a dose during the summer – much higher than Pfizer, at $20 (£15).

The Oxford/AstraZeneca vaccine will be much cheaper, with the company saying it will cost the government “the same as a cup of coffee”, with Sky News understanding that will be a little under £3.

AstraZeneca said it will not sell it for a profit so it is available to all countries, no matter the size of their economy.

Moderna – a commercial company – has an interest in making profits while the researchers for Pfizer made sure it will be made not-for-profit as long as the pandemic continues.

Dr Zoltan Kis, research associate at the Future Vaccine Manufacturing Hub, Imperial College London, said the Moderna vaccine’s higher mRNA amount per dose (100 micrograms) compared with Pfizer’s (30 micrograms) meant the latter could be produced in higher numbers and at lower cost.

He added that transport issues with Pfizer may counteract that initial advantage, but pointed to the higher temperature at which the Moderna candidate could be stored.

“Therefore, once approved by the regulatory authorities, Moderna’s COVID-19 vaccine can be distributed substantially easier and at lower costs compared to the BioNTech/Pfizer vaccine,” he said.

UK availability

The UK government has secured around 40 million doses of the Pfizer vaccine – enough for 20 million people or about a third of the UK population.

It expects 10 million of these doses to arrive before the end of this year, with those chosen to get the jab receiving two doses, 21 days apart.

The UK has ordered five million doses of the Moderna vaccine, to be delivered by spring. Health Secretary Matt Hancock said this candidate would not be available anywhere in Europe until then.

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The government has reserved 100 million doses of the Oxford vaccine, which it has helped fund, with four million expected to be rolled out by the end of the year if it is approved by the medicines’ regulator.

Mr Hancock said the bulk of the Oxford jabs will be administered in 2021.

Moderna’s first target is the US market since it has been developed with the help of the federally funded National Institutes of Health and the US Department of Health and Human Services, so could be even more expensive for the UK.

It has also received $2.4bn (£1.8bn) funding from the US government and plans to have 20 million doses available for use in the US by the end of the year – meaning other countries must form an orderly queue.

 Sky News

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