by Angelica Vellore
Global vaccine roll-out is up and running—but the AstraZeneca controversies stand in its way.
Germany restricts use of AstraZeneca vaccine to over 60s in most cases
The first reported cases of COVID-19 date back to December 2019 in Wuhan, China. COVID-19 is a part of the large family of coronaviruses that causes cold-like illnesses in individuals, while others cause illness in certain types of animals. It is commonly spread from close contact, within 6 feet, mainly because of airborne transmission. The current strain has around a 7.26% mortality rate overall, but it is for elderly people. COVID-19 has impacted the world in every aspect, from daily tasks such as purchasing groceries to a larger scale such as stocks and large businesses. Many are ready for the pandemic to end and return pre-COVID life. Wearing a mask and sanitizing are effective practices, but more efforts will be required. A substantial amount of this is creating a vaccine for the virus.
Many wonder why the current vaccines were developed so quickly. The answer is relatively simple—researchers had already made progress in developing vaccines for other coronaviruses. Essentially, they applied the information from the 2003 Sars epidemic, the 2012 MERS outbreak, and the vaccine for Ebola. As well as the obvious reason that the spread of COVID and the effect that it has on daily life, has pushed for billions of dollars to deliver the vaccine. Typically vaccines take around 7 years to develop, but it took about a year to create the COVID vaccine. The main factor was that stages of development were being done at the same time. This was a huge factor in why these vaccines were developed very quickly.
One of these vaccines is the AstraZeneca vaccine, developed by Oxford. In brief, it is a European COVID-19 vaccine that is taken in two full doses. Andrew Pollard, part of the Oxford vaccine Group, led the Oxford vaccine clinical trials in the UK, Brazil, and South Africa. The region's story is that while he was on a plane, he met John Edmunds of the United Kingdom Scientific Advisory Group for Emergencies. After seeing COVID-19 when it was emerging he predicted how devastating it would be.
The AstraZeneca vaccine, as many of the current vaccines, use a large portion of the spike protein. Then, they put it into a harmless virus. This vaccine, however, utilizes a weakened version (an attenuated virus), of a common cold virus(adenovirus) from chimpanzees. The attenuated virus has been modified to look like the coronavirus. The new virus, along with the spike protein, is injected into the patient. The vaccine enters the cells and then begins to produce the spike protein. The body’s immune system reacts and produces antibodies and activates T-cells to Destroy the cells with a spike protein. So, in the future, should the patient come in contact with COVID-19, antibodies and T-cells are triggered to fight the virus. Because of that, the vaccine provides a 76% efficacy against symptomatic COVID.
The vaccine is in two doses, as mentioned before, though the original strategy was to have it composed as one dose. During clinical trials, there was a subgroup where they administered two and found that this group had a much better immune response. After going back to regulators, it was decided to move to this strategy. Once this was done, it took some time to manufacture additional doses. Furthermore, the delay led to data on different intervals when the second dose was administered. A notable phenomenon was recorded: the longer the time interval, the better the immune response was. This is also seen with other vaccines, like for cervical cancer.
Though there have been significant drawbacks to the vaccine. Many European Countries have pulled back, or suspended administering the vaccine to the rise of blood clots in individuals who have taken the vaccine. Stephen Evans, a professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine, commented, “The problem with spontaneous reports of suspected adverse reactions to a vaccine [is] the enormous difficulty of distinguishing a causal effect from a coincidence.” Meaning that COVID itself has caused blood clotting, so it is hard to determine if it is from the vaccine or the virus itself. According to Dr. Carolyn Kwochten—the chair of the national advisory committee on immunization, “We don't know exactly why but some people will develop autoantibodies that will trigger the platelets to then just clot together and so when these platelets clot together that's when you have your clot somewhere you and we've seen mainly clots in the brain or your abdominal circulation or the pulmonary circulation/” Then, she also reminded that the rates of blood clots were outweighed by the risk of not taking a vaccine.
These blood clots have also caused Canada to change guidance on the vaccine 3 times. From first saying that it is not recommended for individuals over 65, then it is stating is acceptable, and finally advising that it should not be administered to anyone younger than 55. This is mainly because blood clots have only impacted individuals under 50 years of age. The reason for this is still unknown. Though, it was said if you have already taken the vaccine and not had issues for 4-14 days, there should not be issues. Once again, Canada is not the only country to be skeptical about the virus. Sweden, Germany, and France have all restricted AstraZeneca.
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https://www.bbc.com/news/health-55302595
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Wise, J. (2021). Covid-19: European countries suspend use of Oxford-AstraZeneca vaccine after reports of blood clots. https://doi.org/10.1136/bmj.n699