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The vaccine developed by the University of Oxford and the AstraZeneca vaccine will launch from Monday in the UK. Several other countries will follow in the coming weeks.
Here’s the science behind the jab:
The vaccine, called ChAdOx1 nCoV-19, uses a weakened, harmless version of a common virus that causes a cold in chimpanzees.
Researchers have already used this technology to produce vaccines against a number of pathogens, including influenza, Zika, and Middle East respiratory syndrome (Mers).
The virus is genetically modified, making it impossible for it to grow in humans.
Scientists have transferred the genetic instructions for the coronavirus-specific “spike protein” that it needs to invade cells into the vaccine.
When the vaccine enters cells inside the body, it uses this genetic code to produce the surface spike protein of the coronavirus.
This induces an immune response, which prepares the immune system to attack the coronavirus if it infects the body.
Data from the phase 3 trial showed that jab was 70.4% effective on average in two different dose regimens, and possibly up to 90% when half the dose is administered followed by an additional full dose.
The MHRA has recommended that those 18 years of age and older receive two doses to be administered four to 12 weeks apart.
Yes. Pfizer and Moderna pricks are messenger RNA (mRNA) vaccines.
Conventional vaccines are produced using weakened forms of the virus, but the mRNAs use only the genetic code of the virus.
An mRNA vaccine is injected into the body where it enters cells and tells them to create antigens.
These antigens are recognized by the immune system and prepare it to fight the coronavirus.
No real virus is needed to create an mRNA vaccine. This means that the rate at which the vaccine can be produced is accelerated.
The Pfizer, AstraZeneca, and Moderna vaccines have been shown to elicit both an antibody and T-cell response.
Antibodies are proteins that bind to foreign invaders in the body and tell the immune system to act.
T cells are a type of white blood cell that seek out infected cells in the body and destroy them.
Almost all effective vaccines induce both an antibody and a T-cell response.
A study on the AstraZeneca vaccine found that T cell levels peaked 14 days after vaccination, while antibody levels peaked after 28 days.
Yes. The UK government has obtained 100 million doses of the vaccine from the University of Oxford and AstraZeneca as part of its contract, enough for the majority of the population.
UK Vaccine Task Force Director Kate Bingham has said she is confident it can be produced at scale and AstraZeneca said it aims to provide millions of doses to the UK in the first quarter of 2021.
There have been concerns that a Covid-19 vaccine won’t work as well in older people, as does the annual flu shot.
Previous data from the University of Oxford and the AstraZeneca vaccine trial suggest that there have been “similar” immune responses between young and old adults, and Moderna reported the same.
In a statement earlier this year on its phase two data, the University of Oxford said its data marked a “key milestone,” with the vaccine inducing strong immune responses in all adult groups.
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