Britain first to approve Oxford-AstraZeneca’s COVID-19 vaccine, rollout starts Monday

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British regulators have approved a vaccine developed by Oxford University and AstraZeneca that scientists say will massively boost efforts to combat the COVID-19 pandemic.

Unlike the vaccines currently in use – made by BioNTech-Pfizer and Moderna – the Oxford-AstraZeneca vaccine can be stored in regular refrigerators and it has been priced far lower. Scientists say that will make it easier to distribute the vaccine to doctors’ offices, seniors’ homes and throughout developing countries. AstraZeneca said it will produce three billion doses on a not-for-profit basis throughout the pandemic. The company added on Wednesday that it could soon start producing two million doses a week.

The approval by the Medicines and Healthcare products Regulatory Agency was announced at a critical moment in Britain. The country has been struggling with a rampant surge in COVID-19 infections, which scientists believe could be linked to a more contagious variant of the virus that has emerged in recent weeks. That variant has spread to dozens of countries, including Canada, despite bans on British travellers.

The British government has bet heavily on the Oxford-AstraZeneca vaccine and ordered 100 million doses, enough to cover 50 million people since it requires two doses. The first batch has already arrived in the country and inoculations will begin on Monday. Initial doses will be given to as many people as possible with the second dose coming up to 12 weeks later.

The approval was “truly fantastic news and a triumph for British science,” Prime Minister Boris Johnson said Wednesday. “It will allow us to vaccinate more people and also vaccinate them more quickly.”

Britain has already vaccinated around 800,000 people with the BioNTech-Pfizer vaccine. But that vaccine must be stored at -70 C, while the Oxford-AstraZeneca drug can be kept in fridges at between 2 and 8 C. It also costs around $5 a dose compared with $26 for the BioNTech-Pfizer vaccine and $43 for Moderna’s.

The number of daily cases in Britain has jumped 40 per cent in the last week and hit a record high of more than 53,000 on Tuesday. Hospital admissions have reached levels not seen since the pandemic began last March. Most of the country has been put under near total lockdown, and on Wednesday, Health Secretary Matt Hancock announced further restrictions.

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“The regulator’s assessment that this is a safe and effective vaccine is a landmark moment,” said Professor Andrew Pollard, director of the Oxford Vaccine Group. “Though this is just the beginning, we will start to get ahead of the pandemic, protect health and economies when the vulnerable are vaccinated everywhere.”

The Oxford-AstraZeneca vaccine has been in development since last January. It uses a weakened version of a common cold virus that causes infections in chimpanzees but is harmless to humans. Once modified with the genetic sequencing of the spike protein found in COVID-19, the vaccine prompts the human immune system to react.

That’s different from the Pfizer-BioNTech and Moderna vaccines, which involve messenger RNA, or genetic coding, that instructs the vaccinated person’s cells to produce the viral protein, or antigen. That gives the immune system a preview of what the real virus will look like, without causing illness, so it can build defences.

Approval of the Oxford-AstraZeneca vaccine has taken longer than the other two vaccines because of complications in the testing process.

Initially, the vaccine was supposed to be administered in two full doses, as with the Pfizer-BioNTech and Moderna vaccines. However, a mistake in the trials saw only half a dose administered to a small number of volunteers, followed by a full second dose. That combination appeared to be more effective, and initial findings showed it yielded 90-per-cent protection as opposed to 62 per cent in some trials for the two full doses. After pooling data from further trials around the world, AstraZeneca said the average efficacy was 70.4 per cent.

By contrast, the two other vaccines showed 95-per-cent efficacy during trials.

On Wednesday, the MHRA approved the two-full-dose regime of the Oxford-AstraZeneca vaccine. The agency examined further unpublished data from the trials and confirmed that the vaccine was 70-per-cent effective after the initial dose. It was 80-per-cent effective after the second dose, the agency added. The MHRA didn’t provide details on how it came to those conclusions but promised to publish its findings.

Sir Munir Pirmohamed, chair of the MHRA’s Commission on Human Medicines Expert Working Group, said that an analysis of data from the half-dose, full-dose combination found that the results had not been borne out. The 90-per-cent efficacy likely had more to do with the larger time interval between doses, rather than the size of the doses, he said.

June Raine, chief executive of the MHRA, said data showed that the Oxford-AstraZeneca vaccine was effective 21 days after the first dose. She added that initial doses of the Oxford-AstraZeneca and Pfizer-BioNTech offered enough protection that the second doses could be administered three months later.

“The public and everyone who’s listening can be absolutely confident that the scientific rigour of our assessment has been as we would normally do it according to guidelines and standards,” Dr. Raine said.

Public-health officials and scientists said approving the Oxford-AstraZeneca vaccine was a critical moment in the pandemic. “At a time when we see the pandemic accelerating beyond our control, a rapid, efficient vaccination program with good population coverage is our only way out,” said Daniel Altmann, professor of immunology at Imperial College London. “With two vaccines now in the rollout and very substantially more doses, it starts to look realistic that this could be achievable by the spring or early summer.”

How the Oxford-AstraZeneca drug works

16/16

14/14

11/11

The Oxford University and AstraZeneca Covid-19

vaccine can prevent up to 90 per cent of people

contracting coronavirus when it is administered as

a half dose followed by a full dose

at least one month apart

Spike

protein

Spike protein:

Gene is cut from

Sars-CoV-2 genome

Virus

genome

Gene: Inserted into DNA

of adenovirus which acts

as vector in vaccine

Gene

Adenovirus:

Unable to

cause disease

Vaccine: Induces spike

protein antigen – triggers

antibody immune response

Antibodies

Human immune

system: Produces

antibodies against

spike proteins

Vaccine: Can be

stored in refrigerator

at 2-8°C. Two doses

of vaccine are

required

graphic news, SOURCE: Reuters; Oxford

Vaccine Trial; University of Oxford

16/16

14/14

11/11

The Oxford University and AstraZeneca Covid-19 vaccine

can prevent up to 90 per cent of people contracting

coronavirus when it is administered as a half dose

followed by a full dose at least one month apart

Spike

protein

Spike protein:

Gene is cut from

Sars-CoV-2 genome

Virus

genome

Gene: Inserted into DNA

of adenovirus which acts

as vector in vaccine

Gene

Adenovirus:

Unable to

cause disease

Vaccine: Induces spike

protein antigen – triggers

antibody immune response

Antibodies

Human immune

system: Produces

antibodies against

spike proteins

Vaccine: Can be

stored in refrigerator

at 2-8°C. Two doses

of vaccine are

required

graphic news, SOURCE: Reuters; Oxford Vaccine Trial;

University of Oxford

18/18

16/16

13/13

The Oxford University and AstraZeneca Covid-19 vaccine can prevent

up to 90 per cent of people contracting coronavirus when it is administered

as a half dose followed by a full dose at least one month apart

Spike protein

Adenovirus:

Unable to

cause disease

Gene

Virus genome

Spike protein:

Gene is cut from

Sars-CoV-2 genome

Gene: Inserted into DNA

of adenovirus which acts

as vector in vaccine

Antibodies

Vaccine: Induces spike

protein antigen – triggers

antibody immune response

Human immune

system: Produces

antibodies against

spike proteins

Vaccine: Can be

stored in refrigerator

at 2-8°C. Two doses

of vaccine are required

graphic news, SOURCE: Reuters; Oxford Vaccine Trial; University of Oxford

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