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Weigh up risks of blood clots before giving AZ vaccine to certain patients, GPs told

at-risk chickenpox

GPs should only give the Oxford/AstraZeneca Covid vaccine to patients with medical conditions which put them at higher risk of developing blood clots if the benefits outweigh the risks, the UK medicines regulator has said.

The Medicines and Healthcare products Regulatory Agency (MHRA) has issued the advice to healthcare professionals regarding while it continues to review a link between the vaccine and rare blood clots.

It has also added to previous advice regarding symptoms for patients to look out for following their Covid vaccination with the AZ vaccine.

The new advice from the MHRA said:

  • 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.
  • Pregnancy predisposes to thrombosis, therefore women should discuss with their healthcare professional whether the benefits of having the vaccine outweigh the risks for them.

Meanwhile, ‘anyone who has symptoms four days or more after vaccination is advised to seek prompt medical advice’. These include:

  • a new onset of severe or persistent headache, blurred vision, confusion or seizures
  • develop shortness of breath, chest pain, leg swelling or persistent abdominal pain,
  • unusual skin bruising or pinpoint round spots beyond the injection site

The MHRA previously said patients with a headache lasting more than four days after their Covid vaccination should ‘seek medical attention’ as a precautionary measure to rule out thrombosis.

The Government’s independent vaccines advisory body meanwhile said that ‘all individuals offered a vaccine ‘should be fully informed about the benefits and risks of vaccination’.

The JCVI said this should include ‘clear information on the extremely rare thrombosis/thrombocytopenia adverse event, how to monitor for symptoms that might be related to the adverse event, and what action should be taken by individuals and health professionals in the event of such symptoms arising’.

The JCVI also recommended that under-30s in phase 1 of the vaccination programme, who have yet to receive their vaccine, should receive an alternative type of vaccine if one was available.

It is still reviewing whether the AZ vaccine should be offered to under-30s in phase 2 of the vaccination rollout, which includes healthy adults aged under 49 and has yet to begin.

It stressed that while the side effects review is continuing, based on the current evidence the benefits of the AZ Covid vaccine continue to outweigh the risks for the ‘vast majority’ of people.

The MHRA has had 79 case reports of thrombosis following the first dose of the AZ vaccine, out of which 19 people have died.


Hank Beerstecher 10 April, 2021 7:27 pm

OK, I am a GP. Admitted not the sharpest tool in the box. Reading up the vaccine induced thrombosis/thrombocytopenia (VITT) theories* the ‘normal’ risk factors for DVT do not apply to the subgroup of patients developing the anti PF4 (whatever that is) antibodies thought to cause the complications.
So how am I to manage the punters looking for answers whether they should be vaccinated? Any answers from the buck-passing MHRA?
If you want an expert opinion on VITT as well as any other unanswerable query: CGP