Astra Zeneca vaccine & low platelets/blood clot risk: Should MDS patients be concerned?

Following news on the extremely rare risk of blood clots/thrombosis in patients who had the Astra Zeneca vaccine, we are posting several statements by the MHRA, JCVI and BSH on this topic.

We have also asked a number of MDS experts, whether MDS patients should be concerned.

MDS experts' opinion

The consensus from the MDS experts is that the mechanism of action leading to low platelets in MDS is different, so the type of low platelet count associated with the vaccine is not the same, and would suggest currently there is no change in the guidance for MDS patients.

In addition, the blood clot issues are largely confined to younger women.

So - as you will read in the MHRA statement, if you are a younger woman with MDS, or have a history of blood clots, or are on blood thinners already, do seek additional advice from your haematologist before having the 2nd vaccine.

Everyone else is advised to go ahead and have the 2nd dose of the vaccine, as the benefits far outweigh the extremely small risk of these blood clots, especially as the 2nd dose has been shown to improve efficacy in blood cancer patients.

The MHRA are now issuing updated guidance for healthcare professionals on how to minimise risks, as well as further advice on symptoms for vaccine recipients to look out for 4 or more days after vaccination.

Report from the MHRA - blood clots and Astra Zeneca vaccine

‘By 31 March, 20.2 million doses of the COVID-19 Vaccine AstraZeneca had been given in the UK, meaning the overall risk of these blood clots is approximately 4 people in a million who receive the vaccine.

The data suggest there is a slightly higher incidence reported in the younger adult age groups and we are advising that this evolving evidence should be taken into account when considering the use of the vaccine.’

The benefits of vaccination continue to outweigh any risks but the MHRA advises careful consideration be given to people who are at higher risk of specific types of blood clots because of their medical condition.

As a precaution, administration of COVID-19 Vaccine AstraZeneca in people of any age who are at higher risk of blood clots because of their medical condition should be considered only if benefits from the protection from COVID-19 infection outweighs potential risks.

Anyone who experienced cerebral or other major blood clots occurring with low levels of platelets after their first vaccine dose of COVID-19 Vaccine AstraZeneca should not have their second dose.

Anyone who did not have these side effects should come forward for their second dose when invited.

While the MHRA continues to investigate these cases, as a precautionary measure anyone that develops symptoms after vaccination is advised to seek prompt medical advice, such as:

  • shortness of breath, chest or persistent abdominal pain, leg swelling
  • blurred vision, confusion or seizures
  • unexplained pin-prick rash or bruising beyond the injection site

Furthermore anybody with new onset of severe or persistent headache that does not respond to simple painkillers starting four days or more after vaccination should speak to their doctor.'

Read more via the link below:

JCVI - Astra Zeneca and blood clot/thrombosis

JCVI statement on use of the AstraZeneca COVID-19 vaccine: 7 April 2021:

'To date, there are no reports of the extremely rare thrombosis/thrombocytopenia events following receipt of the second dose of the AstraZeneca COVID-19 vaccine.

All those who have received a first dose of the AstraZeneca COVID-19 vaccine should continue to be offered a second dose of AstraZeneca COVID-19 vaccine, irrespective of age.

The second dose will be important for longer lasting protection against COVID-19.'

Read more via the link below:

British Society of Haematology expert guidance to clinicians

The BSH – British Society of Haematology is also providing expert guidance to clinicians, and an opportunity to advise them further in MDT’s (multi-disciplinary meetings), if necessary.

Read more via the link below:

All 3 organisations will issue further updates and advice, as new data comes through. We will be sharing news on our website and on the weekly e-Newsletter, as always.

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