Developed by the University of Oxford and AstraZeneca, the vaccine will roll out Monday when the NHS ramps up its coronavirus immunization program.
– How does the vaccine against AstraZeneca / Oxford work?
The vaccine – called ChAdOx1 nCoV-19 – uses a harmless, weakened version of a common virus that causes a cold in chimpanzees.
Researchers have already used this technology to make vaccines against a number of pathogens, including the flu, Zika, and the Middle East Respiratory Syndrome (Mers).
The virus is genetically modified in such a way that it cannot grow in humans.
Scientists have transferred the genetic instructions for the specific “spike protein” of the coronavirus, which is needed to penetrate cells, to the vaccine.
When the vaccine penetrates cells in the body, it uses this genetic code to produce the coronavirus’ surface spike protein.
This induces an immune response that causes the immune system to attack the coronavirus when it infects the body.
– How effective is it?
Phase 3 study data showed that the burst was 70.4% effective on average over two different dosing regimens and possibly up to 90% when half a dose was given followed by another full dose.
– What dosage regimen has the regulatory authority recommended?
The MHRA has recommended that those over the age of 18 should receive two doses four to 12 weeks apart.
– Is it different from the Pfizer and Moderna vaccine?
Yes. Pfizer and Moderna’s jabs are messenger RNA (mRNA) vaccines.
Traditional vaccines are made using weakened forms of the virus, but mRNAs only use the virus’ genetic code.
An mRNA vaccine is injected into the body, where it enters the cells and prompts them to produce antigens.
These antigens are recognized by the immune system and prepare it to fight the coronavirus.
No actual virus is needed to make an mRNA vaccine. This means that the speed at which the vaccine can be made is accelerated.
– What about antibodies and T cells?
The Pfizer, AstraZeneca and Moderna vaccines have been shown to elicit both an antibody and a T cell response.
Antibodies are proteins that bind to the body’s foreign invaders and tell the immune system that it needs to take action.
T cells are a type of white blood cell that hunt down and destroy infected cells in the body.
Almost all effective vaccines induce both an antibody and a T cell response.
A study with the AstraZeneca vaccine found that T cell levels peaked 14 days after vaccination, while antibody levels peaked after 28 days.
– Can the Oxford vaccine be made to scale?
Yes. The UK government has received 100 million doses of the vaccine from Oxford University and AstraZeneca under its contract, enough for most of the population.
UK Vaccine Task Force Leader Kate Bingham said she was confident it could be manufactured on a large scale, and AstraZeneca said it plans to deliver millions of doses to the UK in the first quarter of 2021.
– Can this vaccine help the elderly?
There have been concerns that a Covid-19 vaccine might not work as well as the annual flu shot in the elderly.
Previous data from the Oxford University and AstraZeneca vaccine study suggest that “similar” immune responses may have occurred in younger and older adults, which Moderna reports.
In a statement earlier this year on the second phase data, Oxford University said their data represented an “important milestone” as the vaccine elicited strong immune responses in all adult groups.
– What else does the UK have access to?
The government has pre-ordered a total of 100 million doses of Oxford’s vaccine, which is almost enough for most of the population.
Late deals were also closed for seven million cans of Moderna Jab from the United States.
The offerings cover four different classes: adenoviral vaccines, mRNA vaccines, inactivated whole virus vaccines and protein adjuvant vaccines.
The UK has secured access to:
– 100 million doses of the Oxford vaccine
– 60 million doses of the Novavax vaccine
– Around 30 million cans from Janssen
– 40 million doses of the Pfizer / BioNTech vaccine (the first agreement the companies signed with a government)
– 60 million doses of a vaccine developed by Valneva
– 60 million doses of protein adjuvant vaccine from GlaxoSmithKline (GSK) and Sanofi Pasteur
– Seven million doses of the batch offered by Moderna in the US
– How do we know the vaccines are safe?
Researchers report that their studies did not suggest any significant safety concerns.
– Aren’t other countries working on vaccines?
Yes. Russia’s coronavirus vaccine is up to 91.4% effective in preventing people who develop Covid-19 symptoms, according to its developers.
The interim results of the third phase of the Sputnik V vaccine study were based on data from volunteers who received both the first and second doses of the Sputnik V vaccine or placebo at the third and final checkpoint.
The Russian Direct Investment Fund announced that it will prepare a report on accelerated registration in various countries.
Preliminary studies suggest that a Chinese coronavirus vaccine candidate appears safe and elicits an immune response in healthy volunteers.
Phase 1/2 studies of an inactivated Sars-CoV-2 vaccine candidate – CoronaVac – recruited more than 700 healthy volunteers between the ages of 18 and 59 in China between April 16 and May 5.
Based on preliminary results, the vaccine appeared to be safe and well tolerated at all doses tested.
Phase 3 studies with the vaccine are continuing.
– When could we get back to normal life?
Although it is not known exactly how long it could take for the population to be vaccinated, Health Secretary Matt Hancock looks like things will return to normal after Easter.
But until then, and until there is some kind of herd immunity in the population that is achieved through vaccinations, people will have to keep wearing face masks, social distancing themselves, and washing their hands.
Prime Minister Boris Johnson previously said there could be a potential transition point before Easter, when enough vulnerable and elderly people have been vaccinated – which could lead to the implementation of new social distancing measures.
And Mr. Hancock said he hoped the permit would provide a “way out”.
He told Sky News the regulators’ decision to recommend that the second dose of the Oxford vaccine can be given up to 12 weeks after the first in order to expedite adoption.