What we know about the Oxford-AstraZeneca Covid vaccine which healthcare workers will soon receive

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  • South Africa will receive one million doses of the Oxford-AstraZeneca vaccine in January
  • Another 500 000 doses are expected next month, with healthcare workers being prioritised
  • The vaccine has already been approved by various regulators and is currently being rolled out in other countries

Health Minister Zweli Mkhize announced on Thursday that South Africa will be receiving one million Covid-19 vaccine doses in January, followed by an additional 500 000 in February from the Serum Institute of India Ltd. which is producing the vaccine developed by AstraZeneca and the University of Oxford, News24 reported.

“We are all happy that the Serum Institute of India and AstraZeneca vaccine has already been approved by various regulators and is being rolled out. SAHPRA is applying reliance on that regulatory framework," Mkhize said.

Here’s a quick refresher on this vaccine, known as ChAdOx1 nCoV-19 or AZD1222, that will soon reach South African shores.

First Covid vaccine to have results published in a medical journal

Oxford University and AstraZeneca became the first major Covid-19 vaccine developers to publish final-stage clinical trial data in a prestigious scientific journal in December, Health24 reported.

Their clinical trial revealed the vaccine was up to 90% effective, depending on the initial dosage. According to the New York Times, the UK authorised the vaccine for emergency use in December, while India authorised a version of the vaccine called Covishield in January.

It incorporates well-known vaccine technology

The Oxford-AstraZeneca vaccine is based on a different technology to Pfizer-BioNTech and Moderna’s vaccines.

This vaccine uses familiar technology – a kind of chimpanzee cold virus, called an adenovirus-vector technology, that has been used in experimental vaccines given safely to thousands of people for diseases ranging from TB and malaria to MERS and Ebola, The Guardian reported. Scientists quickly modified the platform to achieve a Covid-19 vaccine.

The other two vaccines, however, use genetic material called mRNA, or messenger RNA, which tells human cells how to make coronavirus spike proteins. This technology is new to the vaccine field and has received approval by regulators for the first time.   

Two-dose regimen

This vaccine requires two doses, administered four weeks apart, to prime the immune system to fight off the Covid-19 virus. However, during the vaccine’s clinical trial, different doses of the vaccine were unwittingly given to volunteers. However, the “wrong” (half) dose of the vaccine surprisingly turned out to be 90% effective at preventing Covid-19. 

In contrast, the combination of two full-dose shots led to 62% efficacy. The New York Times explains that the researchers who headed the trial speculated that the lower first dose did a better job of mimicking the experience of an infection, therefore promoting a stronger immune response when the second jab was given.

However, an article published yesterday in the BMJ quotes Public Health England who suggests that “a single dose [of the Oxford vaccine] will provide high short-term protection against severe disease”.

Simpler storage and transport

Storage of Pfizer-BioNTech’s mRNA vaccine is challenging for many countries, including South Africa, Health24 previously reported. This is because it needs to be stored and transported at below-freezing temperatures – minus 70 degrees Celsius to be exact. If this isn’t applied, the vaccine can be damaged and become less effective.

Unfortunately, South Africa’s public and private health sector doesn’t have the required facilities to store this vaccine. Similarly, Moderna’s mRNA-1273 jab is likely to pose a problem in SA, as it needs to be stored at minus 20 degrees Celsius

Oxford-AstraZeneca’s vaccine, however, is easier to transport and store as it can be stored at fridge temperatures of 2–8 degrees Celsius. 

The most cost-effective Covid-19 vaccine

For low- and middle-income countries such as South Africa, the cost of the Oxford jab is also more appealing compared to the Pfizer-BioNTech and Moderna vaccines. Pfizer-BioNTech’s vaccine costs reportedly around R299 per dose, while Moderna’s vaccine will cost R536 per jab, Bloomberg notes. However, Fin24 reported that Pfizer and BioNTech have offered discounted doses (around R127 per dose) to SA.  

The Oxford-AstraZeneca vaccine, on the other hand, has the lowest price at R54 per dose and has a longer shelf life compared to the other two vaccines.

South Africa plans to source the bulk of Covid-19 vaccines from AstraZeneca, and the remaining vaccines from Johnson & Johnson and Pfizer. While Johnson & Johnson’s vaccine has not yet gained regulatory approval, the company has agreed with Durban-based Aspen Pharmacare Ltd. to have its version manufactured in the country.

READ | Covid-19 vaccines: Single jab of current two-dose regimens may offer greater population benefit

READ | Ivermectin not a treatment for Covid-19, warns SA expert

READ | SA Covid-19 variant: Is it more dangerous than UK variant? Will the vaccines work on it? Experts weigh in

Image credit: Getty Images

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