The European Medicines Agency concluded its preliminary review of AstraZeneca's COVID-19 vaccine of AstraZeneca's COVID-19 vaccine Thursday, finding that the drug is not associated with an increase in the overall risk of blood clots in those who receive it.
The finding comes after the deaths of patients in Norway and in Denmark who had begun receiving the vaccine. Earlier this week, France, Germany, Italy and Spain joined Austria and other EU nations that had paused their rollouts of the AstraZeneca vaccine pending the EMA's findings.
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"The benefits of the vaccine in combating the still widespread threat of COVID-19 (which itself results in clotting problems and may be fatal) continue to outweigh the risk of side effects," the EMA wrote. Additionally, the EMA found no evidence of a problem related to specific batches of the vaccine, or to particular manufacturing sites.
However, the organization does note that the vaccine may be associated with very rare cases of blood clots associated with thrombocytopenia, a condition that causes an underlying low blood platelet count. Issues with the vessels that drain blood from the brain (CVST) were also reported.
"These are rare cases," the EMA writes, noting that it had identified just 25 total instances of clotting out of 20 million people who have received the AstraZeneca vaccine in the UK and EEA.
"A causal link with the vaccine is not proven, but is possible and deserves further analysis," the EMA says.
The EMA notes that almost all cases of clotting were in women under the age of 55. The organization advises patients who receive the AstraZeneca vaccine to seek prompt medical attention if they experience breathlessness, pain in the chest or stomach, swelling or coldness in the arm or leg, severe or worsening headache, persistent bleeding, multiple small bruises, reddish or purplish spots on the skin or blood blisters beneath the skin.