One million Oxford-AstraZeneca vaccines arrived on South African shores earlier this week and are expected to be administered to healthcare workers within the next two weeks.
Before anyone receives the first jab, the vaccines undergo a technical process of quarantine and quality assurance by the South African Health Products Regulatory Authority (Sahpra).
While there are at least six vaccines approved for use around the world, the AstraZeneca vaccine is what South Africa has to dispense at the moment. Here’s a breakdown of what it’s made of and how long it takes to provide protection against Covid-19.
How is it made and what are the ingredients?
The AstraZeneca vaccine produced in collaboration with Oxford University uses a genetically modified and harmless version of a common cold viral vector (known as an adenovirus) from chimpanzees.
The modified virus is able to grow in humans without causing illness and it is made to look like a coronavirus which triggers an immune response in the body.
When the vaccine is injected into a patient, the body starts producing antibodies to fight the virus. This process primes the body to attack any Covid-19 infection in the future.
The adenovirus has been previously utilised to produce vaccines against the flu, Zika virus, and Middle Eastern Respiratory Syndrome (MERS).
According to the University of Oxford’s Vaccine Knowledge Project, like all other living things, viruses and bacteria need to be kept at the right pH (acid/alkaline level). A number of different products are used in very small quantities to help keep the pH balance right while vaccines are being manufactured.
Here are the ingredients of the vaccine as provided in the AstraZeneca patient information leaflet:
– Chimpanzee Adenovirus - The Oxford-AstraZeneca vaccine uses a cell line called HEK-293 cells. The original cells were taken from the kidney of a legally aborted foetus in 1973.
HEK-293 cells used nowadays are clones of those original cells, but are not themselves the cells of the aborted foetus.
– L-Histidine - this is an amino acid that is also used for arthritis, allergic diseases, ulcers, and anemia caused by kidney failure or kidney dialysis.
– L-Histidine hydrochloride monohydrate - this is considered to be an effective source of the essential amino acid to l‐histidine.
– Magnesium chloride hexahydrate - this compound is used in medicine as a source of magnesium ions, which are essential for many cellular activities.
– Polysorbate 80 (E 433)- this ingredient acts as an emulsifier or an additive which helps liquids to mix and is often used in foods and cosmetics.
– Ethanol, also called alcohol, plays an important role in the vaccine preservation process.
– Sucrose, or sugar, is used as a stabiliser and to keep the vaccine effective after manufactured.
– Sodium chloride - this is the chemical name for salt and it is used to help boost the body’s response to the vaccine.
– Disodium edetate (dihydrate) - this also serves as a preservative in the vaccine.
– Water for injections.
How long it takes to work
The AstraZeneca vaccination course consists of two separate doses of 0.5 ml each. The second dose should be administered between 1-3 months after the first dose.
Generally, a protective effect against Covid-19 starts to develop 7-10 days after immunisation, although people may not be fully protected until 15 days after the second dose is administered.
A pre-print study in The Lancet, found the vaccine gives around 76% protection after the first dose and after an inter-dose interval of 12 weeks or more, the vaccine efficacy increased to 82%.
The study also found that the vaccine provided full protection against severe disease and kept people out of hospital more than three weeks after the first dose.
According to the Centers for Disease Control and Prevention (CDC), it typically takes a few weeks for the body to build immunity after vaccination.
“That means it’s possible a person could be infected with the virus that causes Covid-19 just before or just after vaccination and still get sick. This is because the vaccine has not had enough time to provide protection,” reads the statement on the website.
Even those who have received their second doses of the vaccine and are possibly fully protected are urged to continue following lockdown measures, as this is widely viewed as the best method of protection at the moment.