March 22, 2021

Does the COVID 19 vaccine “AstraZeneca” actually cause blood clots?

HealthCOVID 19Current AffairsAnalysis

AstraZeneca is one of the approved and widely used COVID 19 vaccines.

Avatar: Rehobot Ayalew
By Rehobot Ayalew

Rehobot is a lead fact-checker at HaqCheck. She is a trainer and a professional who works in fact-checking and media literacy.

Does the COVID 19 vaccine “AstraZeneca” actually cause blood clots?

The first cases of COVID-19, the disease caused by the novel coronavirus, were first reported in Wuhan City, China, in early December 2019. Since then, over 120 Million cases were confirmed and 2.6 million deaths were registered worldwide, till the day this article was published. The first case in Ethiopia was confirmed on 13 March 2020. The person found positive was a 48-year-old Japanese citizen who had a history of travel. 

Since early 2020, several research teams rose to the challenge and develop vaccines that protect from COVID 19. The vaccine development has been expedited via unprecedented collaboration in the multinational pharmaceutical industry, governments, and the world health organization (WHO).

Vaccines are a mechanism of reducing risks of getting a disease by working with the body’s natural defenses to build protection. It trains the immune system to create antibodies. The vaccine contains an antigen (a killed or weakened form of a virus or bacteria) that prepares the body to recognize and fight the disease if one encounters it in the future. The body first recognizes the invading germ, Produces antibodies (immune system to fight infection), then remembers the disease and how to fight it if exposed to the germ in the future. 

An experimental vaccine is first tested in animals to evaluate its safety. It is then tested in human clinical trials in three phases:

The first phase is giving the vaccine to a small number of volunteers to assess its safety. In phase two, the vaccine is usually given to hundreds of volunteers, closely monitored for any side effects. In the third phase, the vaccine is given to thousands of volunteers to ensure the safety and potential to prevent disease. Once the results of the clinical trials are available, a series of other steps are required before introducing the public vaccination.

Within less than 12 months after the beginning of the COVID-19 pandemic, several vaccines have started to be rolled out. According to the COVID 19 Vaccine tracker, more than 200 additional vaccine candidates are in development, and there are 13 approved vaccines by at least one country. The first mass vaccination program started in early December 2020. Since then, five vaccines, Moderna, AstraZeneca, Pfizer/Biontech, Sinovac, and Beijing Institute of biological product vaccines, have been used and monitored in a wide population after being approved. Of all the approved vaccines, AstraZeneca has had 22 trials in 13 countries and took the leading number by being approved in 74 countries; it was also praised for its cost-effectiveness and easy-to-store advantages. But since early March 2021, there have been some fears and rumors that the shot may have caused some recipients to develop blood clots.

Blood clots are a clump of blood that has changed from a liquid to a gel-like or semisolid state. A blood clot also called a thrombus, is formed as part of a normal repair process of the body, to prevent losing too much blood in certain instances, such as when you’re injured or cut. When a thrombus (blood clot) forms when it is not needed, it can be life-threatening. A blood clot may happen in the artery (arterial clot) or the vein (venous clot). The most common type of clot is called deep vein thrombosis (DVT); it usually happens in one of your legs, but it can also be in the lungs (pulmonary embolism), in the brain (stroke), in the abdomen, and the heart (heart attack). Blood clot is one of the complications observed in COVID 19 patients. This is because inflammation is the immune system’s response to harmful infections. Researchers are reporting a major inflammatory response in patients with COVID-19, that is resulting in a high incidence of clotting.

Even though the precise number of people affected by Blood clot (before COVID) is unknown and the statistics vary, according to a study in the Journal of Thrombosis and Hemostasis, the annual incidence rates of Blood clot range from 750 to 2,690 per 1,000,000 individuals in the population. And 1 in 4 people worldwide is dying from conditions caused by thrombosis (clot). 

According to the CDC, the normal rate of people affected by blood clots is estimated to be 900,000 Americans each year, resulting in nearly 60,000-100,000 deaths. As with the American National Blood Clot Alliance, the chances of developing blood clot are about 1 to 3 in 1000 per year, and on average, 274 people die every day. Every 37 seconds, someone in the western world dies from a blood clot. Nearly 40,000 people die from this preventable disorder in Europe every year, according to an analysis in 2019.

On March 7, 2021, Austria, announced that  AstraZeneca is paused because of the death that occurred due to blood clotting. Following that, Denmark, and Norway other dozen countries, mostly in Europe, have suspended and banned the use of AstraZeneca’s COVID-19 vaccine. As of 15 March 2021, 21 countries, including European countries, Thailand, and the Democratic Republic of Congo, have stopped, and some temporarily suspended the vaccine. Ethiopia on the other hand has received 2.184 million doses of the AstraZeneca COVID-19 vaccine via the COVAX Facility on 07 March 2021.  Minister of health Lia Tadesse(MD) announced that even though there are concerns of blood clotting cases the vaccination will continue till further investigations are done, and the claim is proved.

This being said, the World health organization (WHO) underlined that vaccination against COVID-19 will not reduce illness or deaths from other causes in its statement on 17 March 2021. In addressing concerns over AstraZeneca safety signals the statement added “Thromboembolic events are known to occur frequently. Venous thromboembolism is the third most common cardiovascular disease globally. At this time, WHO considers that the benefits of the AstraZeneca vaccine outweigh its risks and recommends that vaccinations continue.”

The European medicine agency (EMA)’s safety committee, on its 18 March 2021 extraordinary meeting concluded that: COVID-19 itself results in clotting problems and may be fatal, the vaccine is not associated with an increase in the overall risk of blood clots, there is no evidence of a problem related to specific batches of the vaccine or particular manufacturing sites, and the benefits of the vaccine in combating the widespread of the virus continue to outweigh the risk of side effects. The committee also added the vaccine might be associated with very rare cases of blood clots associated with thrombocytopenia (low levels of elements in the blood that help it to clot). 

Ethiopia has been one of the first countries to receive the COVAX AstraZeneca vaccine and started vaccination on 13 March 2020, The minister of Health Dr. Lia stated that it is planned to vaccinate 20% of the population by the end of 2021 and it is going to take a very long time to vaccinate the whole population. Officials are warning that every precautionary measure against COVID 19 should be taken seriously now more than ever underlining everyone should not be distracted by the hopes of getting the vaccine.