The Oxford-AstraZeneca vaccine played a crucial role in combating the COVID-19 pandemic. However, on May 7, 2024, the European Commission made the decision to revoke its authorization for use.
This announcement followed AstraZeneca's application on March 27, 2024, to withdraw the vaccine's marketing authorization in the EU. While media coverage has focused on the vaccine's known adverse events, particularly the rare risk of blood clots, other factors are likely driving this decision.
The first dose of the AstraZeneca vaccine, outside of clinical trials, was administered on January 4, 2021. Throughout that year, approximately 2.5 billion doses were administered, contributing to an estimated 6.3 million lives saved.
During the peak of the pandemic, the AstraZeneca vaccine was a vital tool. It played a significant role during the emergence of the delta variant in India and throughout the first half of 2021. Amidst significant global supply challenges, the AstraZeneca vaccine stood as one of the few available resources during that humanitarian crisis.
Professor Sarah Gilbert spearheaded the Oxford University team instrumental in developing the Oxford-AstraZeneca vaccine. (Image credit: PA Images/Alamy Stock Photo)
Similar to vaccines from Pfizer, Moderna, Novavax, and others, the Oxford-AstraZeneca COVID vaccine underwent rigorous testing, including phase 3 trials involving thousands of participants, which demonstrated its safety and efficacy. It was rolled out in several European countries, including the UK, in early 2021.
Reports of potential adverse events related to blood clots surfaced in February 2021. However, both the UK government and the Medicines and Healthcare Products Regulatory Agency (MHRA) reaffirmed the vaccine's continued use in a statement issued on March 18, 2021. Despite ongoing speculation and investigation, both the European Medicines Agency and the World Health Organization stressed that the benefits of the vaccine far outweighed any potential risks.
During this period, global COVID-19 cases were surging, reaching around 4 million confirmed new cases per week. It is well-documented that COVID-19 infection significantly elevates the risk of blood clots (thrombocytopenia). An analysis conducted in August 2021, involving 30 million vaccinated individuals in the UK, revealed that the risk of thrombocytopenic events was substantially higher following a COVID-19 infection compared to any COVID-19 vaccine.
According to the British Heart Foundation, for every 10 million individuals vaccinated with AstraZeneca, there are 66 additional cases of blood clots in the veins and seven additional cases of a rare type of blood clot in the brain. In contrast, COVID-19 infection is estimated to cause 12,614 additional cases of blood clots in the veins and 20 cases of rare blood clots in the brain.
To provide context, the incidence of blood clot-related risks associated with widely prescribed medications is considerably higher. For instance, the combined contraceptive pill, commonly prescribed to women, carries a blood clot-related risk of around one in 1,000. Similarly, women taking postmenopausal hormone therapy have a risk of approximately one in 300 per year of developing a blood clot.
Lackluster public perception
The AstraZeneca vaccine indeed faced a tarnished public image, much of which was arguably unwarranted. In January 2021, there was subpar reporting in Germany, falsely asserting that the vaccine was only "8% effective in the elderly." This claim, widely circulated, turned out to refer to the percentage of elderly individuals in the study, not the vaccine's efficacy.
The anti-vaccine movement capitalized on this misinformation, contributing to the "infodemic" by spreading false claims, such as unfounded links between the vaccine and female infertility. While COVID-19 infection does heighten infertility risks, there is no evidence linking infertility to the vaccine.
For individuals or families potentially harmed by any medication, including COVID vaccines, compensation schemes exist. However, many claimants encounter challenges and frustrations in accessing compensation. Government-led schemes should enhance transparency in this regard, as misinformation from the anti-vaccine lobby hampers the very groups they purport to assist.
Why, then, did AstraZeneca withdraw this prominent product? One likely reason is the superiority of other COVID vaccines, such as Pfizer and Moderna. While AstraZeneca is effective, mRNA vaccines offer superior efficacy and safety profiles.asma
The initial challenges related to the specialized refrigeration requirements for transporting and storing the Pfizer and Moderna vaccines have been successfully addressed, even in low-income nations. Additionally, mRNA vaccines offer greater adaptability to new variants.
In light of these advantages, orders for the AstraZeneca vaccine are likely significantly reduced compared to previous years. It is being overshadowed by vaccines with superior performance.
For the Oxford-AstraZeneca vaccine, perhaps its era has indeed come to an end. Nonetheless, it has served as a safe and effective tool in the pandemic response for the majority of countries worldwide.
Professor Sarah Gilbert spearheaded the Oxford University team instrumental in developing the Oxford-AstraZeneca vaccine. (Image credit: PA Images/Alamy Stock Photo)