Benefit of vaccination far outweighs the risks from Covid-19, according to heart expert 

The medical director of the Irish Heart Foundation has said that despite 190m people receiving the AstraZeneca vaccine, the risk of low platelets and blood clots possibly associated with vaccination is 'very low probably at about four to 10 in a million'.

The risks from any Covid-19 vaccine should be compared to serious risks from the virus itself, the medical director of the Irish Heart Foundation said.

Dr Angie Brown said despite 190m people receiving the AstraZeneca vaccine, the risk of low platelets and blood clots possibly associated with vaccination is “very low, probably at about four to 10 in a million”.

“All medications carry a very small risk of side-effects. But the benefit of vaccination far outweighs the risks as Covid infection has a significant risk of hospitalisation, mortality, and morbidity,” the consultant cardiologist said.

Covid infection itself can be associated with clotting issues. It's therefore important everyone who is eligible gets vaccinated.

Of the two blood clot types raising concern, Dr Brown has dealt with just one case of cerebral venous sinus thrombosis CVST. 

She said: “Splanchnic vein thrombosis is [also] rare, occurring 25 times less commonly than clots in the legs or lungs.” 

Common blood clotting occurs at a rate of one per 1,000 in Ireland, she said.

Referring to advice to limit this vaccine to the over-60s, Dr Brown said: “Based on the currently available evidence, specific risk factors have not been confirmed.

Younger women more at risk

“But given the limited data it would appear younger women are more at risk of these very rare effects.” 

The European Medicines Agency (EMA) has said 60% of vaccinations in Europe were to women.

The most common symptoms, Dr Brown said, are shortness of breath, chest pain, swelling in the leg or persistent stomach pain. 

Blurred vision, persistent headaches or tiny blood spots beyond the injection point could also be warnings.

We are witnessing the largest mass vaccination campaign in history. Given the high number of people being vaccinated and the attention focused on the vaccines, some rare reactions are to be expected.

A review of 34m doses of the Oxford/AstraZeneca vaccine ‘Vaxzevria’ by the EMA found 169 cases of CVST and 53 of splanchnic vein thrombosis. 

The World Health Organization said almost 200m doses were administered up to early April.

It said: “Rare adverse events following immunisations should be assessed against the risk of deaths from Covid-19.”