While Canada’s COVID-19 vaccine rollout has had its ups and down, one of the rockiest parts has been the bad press surrounding the AstraZeneca vaccine. Hovering at 76% effective compared to the approximately 95% boasted by mRNA vaccines Pfizer and Moderna, many decided they would rather wait for an mRNA vaccine. However, slow shipments of Pfizer and Moderna made AstraZeneca the most widely available vaccine in the country for several months, causing many people to change their tune. In addition to its lower efficacy rate, AstraZeneca has faced bad press from the multiple reports of blood clots induced by the vaccine, known as vaccine-induced thrombotic thrombocytopenia or VITT.
Among the flurry of concern caused by VITT, many articles have appeared on the Internet comparing the vaccine to hormonal birth control, which is also known to carry an increased risk of blood clots. The risk of a blood clot caused by the AstraZeneca vaccine is estimated to be 1 in 250,000, while an estimated 3-9 out of 10,000 people develop blood clots as a result of hormonal birth control. The same problem has been noted with the Johnson & Johnson vaccine in the United States as well.
This has left many wondering why some governments – including those of Canada, the United Kingdom, Italy, France, and Spain – were so quick to restrict or stop the distribution of AstraZeneca after the reports of VITT came in when birth control carries a higher risk yet is not treated as a public health concern. Some believe that this exposes how the medical community dismisses women’s health issues and shows that the risks of birth control are accepted by society because it is only taken by women.
First, it should be noted that a direct comparison between the risks of AstraZeneca and birth control can’t quite be made. Since the vaccine is taken in two doses a few weeks apart and contraception can be taken for years, the former is a short-term risk while the latter is a long-term risk (though if a contraceptive-induced clot does appear, it would most likely be within the first year). Additionally, though they both cause blood clots – which are ultimately dangerous since they restrict blood flow – they cause different types of clots through varying mechanisms.
The clot caused by AstraZeneca is known as cerebral venous sinus thromboembolism, which occurs in the brain. Hormonal birth control, on the other hand, can cause deep vein thrombosis, which arises in the leg, and can travel to the lungs to cause another clot known as a pulmonary embolism. The estrogen in birth control can increase the transcription of genes encoding clotting factors (proteins involved in blood clot formation), increasing the risk of a clot. One study saw a death rate of 40% among 39 patients with VITT and noted that most of the patients were young women, some of whom were on estrogen replacement therapy or oral contraceptives. Meanwhile, the death rate for deep vein thrombosis/pulmonary embolisms lies at 10-30% within a month of diagnosis.
With that being said, there is still a discussion to be had surrounding the comparison between the two. If the risk of blood clots caused by AstraZeneca is serious enough to deter people from getting a vaccine and merit taking the vaccine off the shelves during a pandemic, why is the (higher) risk posed by birth control widely accepted by the government, medical community and public?
One possibility is that governments were put under pressure when the bad press surrounding AstraZeneca began to worry the public. Not wanting COVID vaccine hesitancy to take hold, the Canadian government was quick to impose age restrictions on those who could get AstraZeneca and recommended mixing AstraZeneca with a second dose of an mRNA vaccine.
Vials of various COVID-19 vaccines. (Image Source: Clinical Trials Arena)
Another explanation is that there is, in fact, an element of sexism in medicine associated with the prescription of hormonal birth control. Thanks to the AstraZeneca controversy, it has come out that many women are not properly educated on the risks of their contraceptives. A New York Times article discussing the risk of blood clots in birth control versus the Johnson & Johnson COVID vaccine included several anecdotes from women who had been taking hormonal birth control for decades and were never made aware of the risk of blood clots. Many women have recently taken to social media to express their anger and disappointment at learning that a medication they take daily carries more risks than a vaccine that is being restricted or halted entirely. This demonstrates a failure on the part of physicians to properly educate their patients on the potential side effects of their medications. A spokesperson for the British Pregnancy Advisory Services suggests that honest discussions about hormonal birth control’s potential health risks are often overlooked due to the desire to prevent unwanted pregnancies.
Hormonal birth control is prescribed both as contraception and off-label for a long list of medical conditions – some of which include endometriosis, acne, polycystic ovarian syndrome, and menstrual-related migraines – to girls as young as 11 years old, many of whom stay on it for decades. Oral contraception, a form of hormonal birth control, is the most common form of contraception in Canadian women aged 15-49. With so many women on the pill, it is extremely important that they are aware of its risks, and that these risks be minimized as much as possible. The AstraZeneca versus birth control controversy shows that, to some extent, the risks that women face when taking birth control are largely ignored or normalized by the medical community and general society.
What is the solution? While AstraZeneca can be easily substituted for another COVID vaccine, the use of hormonal birth control shouldn’t be restricted as it is considered one of the simplest and most effective forms of contraception. For the same reason, it isn’t as simple as telling women to simply opt not to take hormonal birth control, especially due to its many off-label uses. First, physicians should fully educate their patients on the side effects of hormonal birth control before prescribing it. Second, the risk should be reduced as much as possible. While hormonal birth control today uses much lower doses of hormone than it did decades ago, there can always be more research done on how to make the pill even safer. Hormonal birth control is so widely used that this should be a priority. While the risks of blood clots between AstraZeneca and birth control can’t be directly compared, this issue demonstrates a widespread indifference to the risk that women take daily in order to have control of their bodies.
