The subcommittee of WHO’s Global Advisory Committee on Vaccine Safety (GACVS) has reviewed the latest information from the European Medicines Agency (EMA), the United Kingdom’s regulatory body MHRA, and other countries as regards the AstraZeneca vaccine.
While the EMA concluded that unusual blood clots with low blood platelets should be listed as very rare side effects of the AstraZeneca vaccine, MHRA says evidence of a link “is stronger but more work is still needed.”
“Based on current information, a causal relationship between the vaccine and the occurrence of blood clots with low platelets is considered plausible but is not confirmed. Specialized studies are needed to fully understand the potential relationship between vaccination and possible risk factors. Rare adverse events following immunizations should be assessed against the risk of deaths from COVID-19 disease and the potential of the vaccines to prevent infections and reduce deaths due to diseases”, the WHO subcommittee said in an interim statement.
The AstraZeneca vaccine constitutes a large part of the portfolio of the COVAX global solidarity initiative, and more than 36 million doses have been shipped worldwide to more than 86 countries. Although cases of blood clotting have been very rare with low numbers, it has been a growing cause of concern and vaccine hesitancy across the world.
Nonetheless WHO is carefully monitoring the rollout of all COVID-19 vaccines, and will continue to work with countries to manage potential risks.