Covid vaccines: What is the difference between the Pfizer, Oxford, Moderna, Valneva, Novavax and Johnson & Johnson jabs

Since the start of the pandemic, scientists around the world have been racing to develop a jab that prevents Covid-19.

In December, the Pfizer/BioNTech coronavirus vaccine beat its rivals to be the first to be approved for use in the UK.

The Oxford/AstraZeneca vaccine is already in circulation and on April 7, the first dose of the Moderna vaccine was given in Wales.

A fourth, fifth, and sixth vaccine is potentially on the way. One is the Janssen jab, from American company Johnson & Johnson, the world’s first single-shot Covid vaccine, which was found to be 66 per cent effective at preventing moderate to severe Covid-19, but offers high protection against people needing to go to hospital, according to trial results. 

Meanwhile, the Government has ordered 60 million doses of another Covid vaccine candidate from Novavax, which is due to be made on Teeside if approved. The jab was found to be 80.3 per cent effective at preventing Covid-19 in UK trials and worked against the new Kent and South African variants.

In other news, the large-scale manufacturing of another potential jab, made by French company Valneva, started in Scotland in January. It is expected to deliver up to 60 million doses to the UK by the end of this year if approved. 

So what are the differences between the vaccines?

Pfizer/BioNtech

Trials have shown the Pfizer/BioNtech vaccine to be more than 90 per cent effective but it has to be stored at minus 70 degrees C so is not the easiest vaccine to use. Patients need two doses. 

It is know as 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 it can be produced is dramatically accelerated.

As a result, mRNA vaccines have been hailed as potentially offering a rapid solution to new outbreaks of infectious diseases.

In theory, they can also be modified reasonably quickly if, for example, a virus develops mutations and begins to change.

mRNA vaccines are also cheaper to produce than traditional vaccines, although both will play an important role in tackling Covid-19.

One downside to mRNA vaccines is that they need to be stored at ultra-cold temperatures and cannot be transported easily.

Moderna

Elle Taylor, 24, who works at a further education college in Llanelli, was the first person in the UK to receive the Moderna jab from staff nurse Laura French at West Wales General Hospital’s outpatients department.

The Moderna vaccine works in a very similar way to the jab from Pfizer/BioNTech.

Coronavirus is studded with “spike proteins” that it uses to enter human cells. Covid-19 vaccines target this spike protein.

The Moderna and Pfizer vaccines use synthetic messenger RNA (mRNA), a genetic material that contains information about the spike protein.

The vaccines provide the body with instructions to produce a small amount of this protein which, once detected by the immune system, leads to a protective antibody response.

Moderna’s vaccine does not require the same ultracold storage as Pfizer’s and can remain stable at normal fridge temperature for 30 days.

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

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.

The jabs, which form part of the 17 million-dose order by the Government,were authorised for temporary use by the UK’s medicines regulator on January 8.

Oxford/AstraZeneca

The vaccine developed by the University of Oxford and pharmaceutical giant AstraZeneca was approved by the MHRA in December last year.

The Oxford jab is not an mRNA vaccine. Instead, it uses a harmless weakened version of a virus that causes the common cold in chimpanzees.

The EMA and the MHRA have both carried out reviews into reports of rare blood clots in people who have had the AstraZeneca vaccine.

Some European countries restricted the vaccine use in younger people following reports of low platelet counts and cerebral venous sinus thrombosis (CVST), a specific type of clot that prevents blood from draining from the brain.

On April 7, the UK’s medicine regulator said that people under-30 should be offered an alternative vaccine. However, experts said the risks of not having an AstraZeneca jab far outweighed any risk of having one.

Professor Calum Semple said he was “not worried one little bit” about headlines around the vaccine. The Sage scientist told LBC: “I’m 53, my risk of death from Covid is about one in 13,000. For me it’s a no-brainer, I need to have the vaccine.”

Oxford data indicates the vaccine has 62 per cent efficacy when one full dose is given followed by another full dose, but when people were given a half dose followed by a full dose at least a month later, its efficacy rose to 90 per cent.

The combined analysis from both dosing regimes resulted in an average efficacy of 70.4 per cent.

In separate research, results showed the jab offers 76 per cent protection up to three months after the first dose and could reduce transmission by 67 per cent.

However, a study of around 2,000 people has shown the jab only offers minimal protection against mild disease of the South Africa variant and, due to the young age of participants, could not conclude whether the jab worked against severe disease.

Health minister Edward Argar said on Monday that Oxford researchers remained confident their vaccine could prevent severe disease for those affected by the variant and that booster jabs to tackle new strains are already in the pipeline.

Valneva

Clinical trials are still ongoing for the Valneva vaccine candidate but manufacturing has started at the French biotech company’s site in Livingston, West Lothian.

The candidate is currently in phase one/two trials and will need approval from the Medicines and Healthcare products Regulatory Agency (MHRA) before it is rolled out.

Initial results from the ongoing clinical study, involving 150 participants at testing sites in Bristol, Southampton, Birmingham and Newcastle, are expected in April.

The vaccine works by using technology already used in existing vaccines that are used for prevention of diseases such as as the flu and Japanese encephalitis. 

It uses inactivated whole particles of SARS-CoV-2 to induce a strong immune response.

Novavax

Novavax, a fourth Covid-19 vaccine could be approved for use in the UK within weeks, as late-stage trials suggested it was 89 per cent effective in preventing coronavirus.

The jab is the first to show in trials that it is effective against the new virus variant found in the UK.

The UK has secured 60 million doses of the jab – to be produced on Teesside – which is believed to offer protection against the new UK and South African variants.

It was shown to be 89.3 per cent effective at preventing coronavirus in participants in its Phase 3 clinical trial in the UK, which involved more than 15,000 people aged between 18-84, of which 27 per cent were older than 65, Novavax said.

The vaccine will now be assessed by the Medicines and Healthcare products Regulatory Agency (MHRA), Prime Minister Boris Johnson said.

Pfizer and Moderna vaccines rely on technology that has not been used in previous vaccines, but the Novavax jab uses a more traditional method of recreating part of the spike protein of the virus to stimulate the immune system.

Like the Oxford vaccine, the Novavax jab can be stored at regular fridge temperature - which means it can be distributed more easily.

In the South African part of the trial, where most of the cases were the South African variant of the virus, the vaccine was 60 per cent effective among those without HIV.

Johnson & Johnson

The Janssen jab, from American company Johnson & Johnson could become the sixth vaccine to be approved in the UK.

The firm said the jab was 85 per cent effective in preventing severe disease “and demonstrated complete protection against Covid-19-related hospitalisation and death as of day 28”.

The jab worked across multiple variants of coronavirus, including the South African variant which has been worrying scientists, the firm said.

The UK has secured access to 30 million doses of the Janssen vaccine from Johnson & Johnson.

The vaccine is estimated to remain stable for two years at minus 20C and at least three months at 2-8C, which will make the logistics of rolling the jab out easier as it can be stored in a standard fridge. It could be available at designated vaccination sites across the UK, alongside existing vaccines.

British regulators have been conducting a so-called rolling review of the data from Johnson & Johnson. This means that rather than waiting until the end of the clinical trial to assess the data, experts from the MHRA have been assessing data on a rolling basis during the trial and helped speed up the approval process.