WHO says no link between AstraZeneca vaccine and blood clots

WHO says no link between AstraZeneca vaccine and blood clots
© Greg Nash

The World Health Organization (WHO) on Friday said there was no risk from taking AstraZeneca's COVID-19 vaccine as some countries have paused distribution over blood clot concerns.

Despite no clear evidence of a link, countries including Iceland, Denmark and Norway have halted their use of AstraZeneca's vaccine following reports that it could be connected to blood clots.

Denmark announced a 14-day pause on Thursday to investigate after reports of dozens of people forming blood clots after receiving the shots, with at least one person dying.


During a briefing Friday, WHO Director-General Tedros Ghebreyesus reiterated that the European Medicines Agency has said there is no indication of a link between the vaccine and blood clots and that the AstraZeneca vaccine can continue to be used.

The WHO’s global advisory committee on vaccine safety is reviewing the reports and will make its findings public, Tedros said, like it does with any safety issues.

Mariângela Simão, a WHO assistant director-general, said she thinks people have confused causation with correlation.

"People die every day," she said, adding that more than 335 million doses of COVID-19 vaccines have been administered globally so far and no deaths have been found to have been caused by the vaccines.

"There will be people who have been immunized who will die of other causes. So far the preliminary data we have seen does not lead to a causal relationship," Simão said.

She added the WHO is "very much aligned with the position" that vaccinations with the AstraZeneca shot should continue until the agency has clarified a causal relationship.


The AstraZeneca vaccine is the main shot being distributed globally as part of the WHO-led Covax effort to share vaccines in developing nations. Covax aims to distribute 2 billion doses this year, providing access for poorer countries.

Also on Friday, the WHO listed Johnson & Johnson's coronavirus vaccine as safe for emergency use in all countries and in its Covax program, clearing the way for the single-shot vaccine to be used more broadly.

The move follows authorization by the European Medicines Agency, which was announced Thursday.

It is the third COVID-19 vaccine to receive WHO backing, following those made by Pfizer-BioNTech and AstraZeneca.

“Every new, safe and effective tool against COVID-19 is another step closer to controlling the pandemic,” Tedros said in a statement. 

“But the hope offered by these tools will not materialize unless they are made available to all people in all countries. I urge governments and companies to live up to their commitments and to use all solutions at their disposal to ramp up production so that these tools become truly global public goods, available and affordable to all, and a shared solution to the global crisis,” Tedros said.