As you likely heard in the news this week, Germany followed by several other European countries paused their roll-out of the AstraZeneca vaccine – which is slated for extensive use in Australia – over fears of unforeseen side effects. The European Medicines Agency (EMA) has said it is reviewing the case this week and is expected to make a further announcement shortly.
The vaccine pause relates to six cases of sinus vein thrombosis and another thrombosis case classed as medically similar, six women and one man altogether. The disease is very serious and difficult to treat, and three of the patients have died.
Seven cases of such a rare disease, all occurring four to 16 days post-vaccination, is statistically significant. There have currently been 1.7 million doses of the AstraZeneca vaccine given in Germany. Based on that figure, according to a report from Germany’s Federal Institute of Vaccines and Biomedicines, they would usually expect approximately one cerebral vein thrombosis case in a 14-day period.
This form of thrombosis is most common among women aged 20 – 50, and especially pregnant women. A risk factor is use of the contraceptive pill, and indeed thrombosis is a listed (very rare) side effect of the pill.
For the AstraZeneca vaccine, however, thrombosis was not previously known as a potential side effect. It now has to be registered as such with the EMA, who will then make an assessment as to safety and cost-benefit calculations. In the report, the EMA signal that because women aged 20 – 50 are not at greatest risk of Covid-19, thus the value of the vaccine may be lower for this group.
Taken together, it all seems to be a simple case of doing due diligence on a formerly unknown potential side effect. The debate currently raging is more concerned with perception and sentiment.
As three Australian epidemiologists commented in The Conversation, “We would urge extreme caution in pausing rollouts while investigations are underway, because once a vaccine rollout is paused, it can sometimes dent vaccine confidence so much that it struggles to recover, as seen in Japan with the Human Papillomavirus vaccine.”
This is a thorny question. In my personal opinion, it is better that the regulators be given the time to make their proper assessments and all of the information is out in the open, rather than left to flourish in the dark corners of the internet as “one surprising fact about the AstraZeneca vaccine that they don’t want you to know!”
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Feature image courtesy of @matnapo via Unsplash.