How does the AstraZeneca / Oxford vaccine work?
The vaccine – called ChAdOx1 nCoV-19 – uses a harmless, weakened version of a common virus that causes the common 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 (Seas).
The virus is genetically modified, so it is impossible for it to develop in humans.
Scientists have transferred the genetic instructions for the specific coronavirus “spike protein” – which it needs to invade cells – to the vaccine.
When the vaccine enters cells inside the body, it uses this genetic code to produce the coronavirus surface spike protein.
This induces an immune response, causing the immune system to attack the coronavirus if it infects the body.
What do the results show?
ChAdOx1 nCov-2019 vaccine has been shown to elicit a robust immune response in healthy adults aged 56 to 69 years and people over 70 years of age.
According to the researchers, the trial volunteers demonstrated similar immune responses in all three age groups (18-55 years, 56-69 years, and 70 and older).
The study of 560 healthy adults – including 240 over the age of 70 – found that the vaccine is better tolerated in the elderly than in young adults.
The volunteers received two doses of the vaccine candidate or a placebo meningitis vaccine.
No serious vaccine-related adverse health effects were observed in participants.
The results are consistent with phase 1 data reported for healthy adults aged 18 to 55 earlier this year.