Facts about the Oxford-AstraZeneca COVID-19 vaccine
The COVID-19 vaccine developed by biopharmaceutical company AstraZeneca and Oxford University is among the candidate vaccines that showed promise in late 2020.
And as of January 2021, several local government units in the country including Pasig, Valenzuela, Caloocan, Mandaluyong, and Iloilo City have already signed a tripartite agreement with AstraZeneca and the national government for the procurement of the said vaccine.
The Oxford-AstraZeneca COVID-19 vaccine/ Source: AstraZeneca
How the Oxford-AstraZeneca vaccine works?
The Oxford-AstraZeneca vaccine is an adenovirus-based vaccine, meaning it contains a modified version of the common cold virus that spreads among chimpanzees and has been used in experimental therapies for decades.
The modified virus that carries the gene from the novel coronavirus's spike protein will then prompt your immune system to produce antibodies that can fight off COVID-19, should you get infected with it.
The Oxford-AstraZeneca is the first of its kind to be approved for human use, but companies like Johnson & Johnson, CanSino, and NantKwest are also producing their own adenovirus-based vaccines.
Differences and similarities from other vaccines
Russia's COVID-19 vaccine Sputnik V, which they developed together with the Gamaleya National Research Institute of Epidemiology and Microbiology, is pretty similar to the Oxford-AstraZeneca vaccine because it is also adenovirus-based.
However, unlike the Oxford-AstraZeneca vaccine that contains modified adenovirus from chimpanzees, Sputnik V has adenovirus vectors or human viruses that are inactive.
Both the adenoviruses in Sputnik V and Oxford-AstraZeneca cannot thrive in the body, meaning humans will not get sick when injected with it.
The modified adenoviruses are only used in the vaccine to create an immune response against the novel coronavirus.
The method of using human adenovirus has long been used in developing vaccines and has been most widely used by the U.S. Army since 1971.
However, in the midst of the COVID-19 pandemic, a new method of developing a vaccine has been used by pharmaceutical and biotech companies like Pfizer and Moderna.
This new, groundbreaking technology is called the mRNA technology, which uses a genetic code instead of a dead or modified sample of the virus in inducing immune response in the body.
This technology has been used in developing COVID-19 vaccines as early as February of 2020.
All four mentioned vaccines (Oxford-AstraZeneca, Sputnik V, Pfizer, and Moderna) require two shots with almost a month of interval in between.
Storage and distribution
In terms of storage and distribution, Oxford-AstraZeneca's vaccine is considered as the easiest to transport among the leading vaccines, since it can be stored up to six months between 36 and 46 degrees Fahrenheit or 2 to 7 degrees Celsius, normal refrigerator temperatures.
Russia's Sputnik V vaccine can also be stored at 2 to 8 degrees Celsius in its lyophilized (dry) form.
Meanwhile, Moderna's and Pfizer's vaccines must be stored at subzero temperature, at -4 degrees and -94 degrees Fahrenheit, respectively, or at -20 and -70 degrees Celsius.
This is because vaccines produced using mRna technology need to be stored in lower temperatures to remain effective and stable.
Costs and efficacy
The reported costs of the leading COVID-19 vaccines are as follows:
Oxford-AstaZeneca - $4 (P192) per dose
Sputnik V - $10 (P480) per dose
Pfizer - $20 (P960) per dose
Moderna - $33 (P1,584) per dose
Keep in mind that these vaccines require two shots so the total price would be double of the indicated price. Plus, these prices are not fixed and are expected to fluctuate as time passes.
As for efficacy, these are the reported efficacy rates of the leading vaccines:
Pfizer - 95% effective after second shot
Moderna - 95% effective after second shot
Sputnik V - 95% effective after second shot
Oxford-AstraZeneca - 70% effective (up to 90% is dosing is adjusted)
Controversies
In early September, the phase 3 clinical trial of Oxford-AstraZeneca was temporarily put on hold after a study participant developed transverse myelitis, or an inflammation of the spinal cord.
And in October 2020, a volunteer participant of the clinical trial in Brazil died. However, an unidentified Bloomberg source said that the deceased participant didn't receive the company's shot and was only part of the control group.
Half of the participants in the control group received the experimental COVID-19 vaccine, while the other half received an established meningitis vaccine. It is believed that the participant who died received the meningitis vaccine.
Despite these controversial incidents, the clinical trials pushed through and Oxford-AstraZeneca's COVID-19 vaccine has been approved for emergency use in countries like the United Kingdom, India, and Mexico.
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Check also the side effects that you should expect when getting the COVID-19 vaccine.