AstraZeneca's logo is reflected in a drop on a syringe needle in this illustration taken November 9, 2020.
DADO RUVIC/Reuters
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 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 is set to arrive in the country this week 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 on Twitter Wednesday. “We will now move to vaccinate as many people as quickly as possible.”
The U.K. 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 approval by the Medicines and Healthcare products Regulatory Agency was announced at a critical moment in the U.K. 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.
COVID-19 news: Updates and essential resources about the pandemic
The number of daily cases in Britain hit a record high of more than 53,000 on Tuesday, and hospital admissions have reached levels not seen since the pandemic began last March. Much of the country has been put under near total lockdown, and on Wednesday, Health Secretary Matt Hancock is expected to announce further restrictions.
“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, as many as possible as soon as possible.”
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 early trials saw only half a dose administered at first, followed by a full second dose. That combination proved to be more effective, yielding 90-per-cent protection as opposed to 62 per cent for the two full doses. By contrast, the two other vaccines showed 95-per-cent efficacy during trials.
The MHRA has approved the two-full-dose regime of the Oxford-AstraZeneca vaccine and said that further data from the trials showed that it was 70-per-cent effective after the initial dose. It was 80-per-cent effective after the second dose, the agency added on Wednesday.
Prof. Sir Munir Pirmohamed, chair of the MHRA’s Commission on Human Medicine’s 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.
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 up to 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. “These are difficult times for so many of us, but vaccines such as this one have the potential to save many lives and will see us come through.”
Dr. Pirmohamed also said the MHRA was not recommending mixing the vaccines – for example giving an initial dose of one vaccine and a second dose of another – but that studies were under way to see whether that would be possible in future.
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
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
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
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
The initial COVID-19 vaccinations in Canada and around the world raise questions about how people react to the shot, how pregnant women should approach it and how far away herd immunity may be. Globe health reporter Kelly Grant and science reporter Ivan Semeniuk discuss the answers. The Globe and Mail
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2020-12-30 13:22:51Z
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