Blood clots are not a typical vaccine side effect, despite questions raised by AstraZeneca's COVID-19 vaccine

• There's no evidence that COVID-19 vaccines, or any others, cause blood clots.
• It's likely a coincidence that some AstraZeneca vaccine recipients have gotten blood clots.
• Some countries have stopped using the AstraZeneca vaccine anyway.

Several European countries have paused their use of the AstraZeneca COVID-19 vaccine due to a few reports of blood clots in those who got the shot.

However, health experts and officials have said there's no evidence that the vaccine causes clots. It's more likely coincidental that some vaccine recipients experienced bleeding abnormalities around the time they received their vaccine.

In fact, AstraZeneca reviewed its vaccination records and found there were fewer events of reported blood clots in the vaccinated population than in the general population.

"No vaccines have been shown to cause blood clots," Daniel Salmon, director of the Institute for Vaccine Safety at Johns Hopkins University, told Insider. He added that he would not be worried about experiencing them as a vaccine side effect, even if he were a person at high risk of blood clots.

Some of the risk factors for blood clots - serious injury or surgery, confinement to bed, pregnancy, and obesity, according to the National Blood Clot Alliance - overlap with the eligibility criteria for COVID-19 vaccines. In many countries, shots are being given first to bedridden residents of long-term care facilities and people with preexisting conditions.

Some countries have stopped using the vaccine, despite WHO recommendations

At least 16 countries have suspended use of the AstraZeneca vaccine since two vaccine recipients - a 60-year-old woman in Denmark and a 49-year-old woman in Austria - died of blood clots or bleeding abnormalities after getting their shots.

The World Health Organization said Friday that countries should continue using the vaccine unless a causal link between the jabs and the clots is proven. Such a link has not been found.

"People die every day. There will be people who are immunized who die of other causes," said Mariangela Simao, WHO's assistant director-general, according to the Washington Post.