Many countries across Europe and into Asia are suspending their COVID-19 vaccination with the AstraZeneca vaccine. These moves come on concerns over the formation of blood clots in some people soon after being inoculated. Several people have developed pulmonary embolism, where the blood clot in the legs has broken off and traveled into the lungs, and a few have died.
On Monday, Germany, France, Italy, and Spain were the latest nations that suspended the vaccine’s use, deciding to rely solely on Moderna and Pfizer vaccines. Last week Denmark, Norway and Iceland, followed by Ireland, paused their vaccination programs. In Denmark, a 60-year-old woman, according to health authorities, died after a blood clot led to a pulmonary embolism. A woman in Bulgaria died after her vaccination. However, her autopsy didn’t reveal blood clots. She did have a history of heart disease, which may have contributed to her death. But any causal relationship to the vaccine has yet to be determined.
According to the pharmaceutical giant, AstraZeneca reported that there had been 37 reports of blood clots out of more than 17 million people who have been administered the vaccine across 27 countries and Britain. The company assured governments that there was no evidence that their vaccine increased the risk of such complications.
On Sunday, the company released a statement, “A careful review of all available safety data of more than 17 million people vaccinated in the European Union and the UK with COVID-19 Vaccine AstraZeneca has shown no evidence of an increased risk of pulmonary embolism, deep vein thrombosis or thrombocytopenia [elevated platelet count—a blood component], in any defined age group, gender, batch or in a particular country.” A review of its published efficacy trial in the Lancet comparing the efficacy of the vaccine versus placebo revealed no difference in adverse events between the two. No mention was made of blood clots occurring in study participants.
Dr. Tedros Adhanom Ghebreyesus, the Director-General of the World Health Organization, said at yesterday’s press brief, “Since our last press conference on Friday, several more countries have suspended the use of AstraZeneca vaccine as a precautionary measure after reports of blood clots in people who had received the vaccine from two batches produced in Europe. This does not necessarily mean that these events are linked to the vaccination, but it is routine practice to investigate them. And it shows that the surveillance system works, and effective controls are in place.”
The WHO advisory committee on vaccine safety has been reviewing the available data and is in contact with the European Medicines Agency.
The European Medicines Agency said they hope to finish their investigations by Thursday and will determine if any further actions are required. It was in their view that “the benefits of the AstraZeneca vaccine in preventing COVID-19, with its associated risk of hospitalization and death” outweighed the rare adverse events.
AstraZeneca has been embroiled in controversy from its inception when press reports confused efficacy results (the results from test trials among selected individuals) with actual effectiveness (in use by large populations). Additionally, a small trial on its efficacy in South Africa and the variant that emerged there further eroded confidence in the vaccine. As well, bitter battles over delivery shortfalls to the EU in January led to political attacks on the company by several European governments. These developments do not offset the more pressing issue that effective vaccines are urgently needed to protect the population, especially as the UK’s more virulent strain is threatening a spring surge throughout Europe.
Germany’s health minister, Jens Spahn, told the Financial Times the move to suspend vaccinating people with the AstraZeneca vaccine arose out of an abundance of caution. “We are all aware of the implications of this decision, and we didn’t take it lightly. It was a technical decision, not a political one. [In order] to maintain trust in the vaccine, we have to give our experts in Germany and the EU time to check the recent incidents.” Approximately 1.6 million people in Germany have received the AstraZeneca vaccine, and there have been seven cases of blood clots in the brain, known as cerebral venous thrombosis.
On Friday, the International Society on Thrombosis and Haemostasis (ISTH) released a statement urging all eligible adults to continue receiving their COVID-19 vaccinations, despite the recent decisions by various national health agencies suspending use on the reports of these blood clots. They wrote, “At this time, the small number of reported thrombotic events relative to the millions of administered COVID-19 vaccinations does not suggest a direct link. Thrombotic events are common in the general population and have not previously been associated with vaccinations.”
The annual incidence of these blood clotting events stands around 1 per 1,000. These rates rise sharply after age 45, approaching five to six per 1,000 annually by age 80. Immobility, obesity, and various health conditions further contribute to these risks in the general population. In the context of the reported number of blood clots reported in vaccinated individuals among the 17 million doses administered, this places the risk of a blood clot far below the background rate for this complication.
Though there haven’t been any similar concerns raised about blood clots with Moderna and Pfizer’s COVID-19 vaccines, in an online forum sponsored by the North America Thrombosis Forum titled “COVID-19 Vaccine and Blood Clots,” several US participants provided their experiences with such adverse events after their vaccinations. Dr. Samuel Goldhaber, Associate Chief and Clinical Director for the Division of Cardiovascular Medicine at Harvard Medical School, raised the more important concerns of blood clots associated with COVID-19 itself and urged continued vaccination.
Causal relationships between vaccination and the development of blood clots are an urgent and pressing issue with the AstraZeneca COVID-19 vaccine in light of the need to vaccinate the population. Any such risks must be balanced against the benefit of the impact COVID-19 has on the population.
It becomes all the more imperative that measures are taken to halt the community transmission of the SARS-CoV-2 virus through sound and effective public health mitigation measures, rather than the reckless reopening that has been undertaken by virtually every capitalist government in Europe and the Americas.