Covid vaccination, thrombosis and GHIC
Arvind Kaul
Consultant Rheumatologist, St. George’s Hospital, London and Medical Expert for GHIC
March 14th, 2021
What are the concerns about the AstraZeneca coronavirus vaccine?
Patients with Antiphospholipid Syndrome will have read with concern reports in the press about the AstraZeneca Oxford coronavirus vaccine and thrombosis (blood clots).
Reports have come from Norway, Denmark and Austria describing a total of four isolated cases of pulmonary embolism or Deep Vein Thrombosis (DVT) after administration of the AstraZeneca coronavirus vaccine. This has led to the temporary suspension of this vaccine from Norway, Iceland, Austria, Estonia, Lithuania, Luxembourg, Italy and Latvia with Ireland considering doing so. These countries have emphasised they have not stopped giving the vaccine permanently but merely suspended it until more information is available.
It is important to remember that inflammatory/immune disease including lupus, Rheumatoid Arthritis, Ankylosing Spondylitis and of course APS, are all associated with a higher risk of thrombosis by themselves. COVID-19 infection as a hyperinflammatory condition, is also associated with an increased risk of thrombosis as are other infections, but the mechanisms have not yet been fully determined.
How does the Astra Zeneca coronavirus vaccine work?
Coronavirus enters human cells by attaching its so-called spike protein, to a receptor ACE2, normally found in human cells. The AstraZeneca vaccine puts the DNA for this spike protein into another virus called Adenovirus, while ensuring this adenovirus cannot also replicate in humans by removing the DNA which would normally allow it to do so. Once the adenovirus is in the human cell, it releases the spike protein DNA, which then travels to the nucleus and instructs the cell to make the coronavirus spike protein. The immune system recognises this and produce anti-Coronavirus antibodies. These causes the person to have immunity at the ready so that any real infection can be dealt with much more quickly and effectively.
What has been the reaction from medical bodies to these reports
The World Health Organisation has stated that there is no robust evidence that the AstraZeneca vaccine causes thrombosis.
The British Medical Journal has published a summary of the issues and has quoted the European Medicines Agency safety committee which has emphasised there is currently no indication that the vaccinations cause thrombosis. Thrombosis is not listed as a side effect because it has not been found either in the very well conducted clinical trials or in postmarketing surveillance to date.
As of 10th March, 30 cases of thrombosis events have been reported among the five million people giving the AstraZeneca vaccine in the European Economic Area. More than 11 million doses of the AstraZeneca vaccine have been administered across the UK and reports of blood clots received so far do not appear to be any greater than would have occurred naturally in the vaccinated population.
AstraZeneca have also stated an analysis of the safety data of more than 10 million vaccine records has shown no evidence of an increased risk of thrombosis in any age group, gender, batch or country. They have emphasised the observed number of these types of thrombosis events from their data is significantly lower in those vaccinated than what would be expected amongst the general population.
The International Society of Thrombosis and Haemostasis (ISTH) released a statement on March 12th, 2021. It recommends all eligible adults to continue to receive their COVID-19 vaccinations despite these recent reports. They have also emphasised that the small number of reported thrombotic events relative to the many millions of administered coronavirus vaccinations does not suggest a direct link to thrombosis.
What should a patient with APS (Hughes’ Syndrome) do
Covid-19 can be fatal by virtue of its ability to cause thrombosis, especially relevant in APS patients. Vaccines afford potential protection against these serious covid-19 effects infection.
GHIC’s advice is that unless your specific circumstances dictate otherwise, with the currently available data, we continue to strongly advise coronavirus vaccination with any of the vaccines currently available including the AstraZeneca vaccine. If there is a very good reason not to have a vaccination such as an allergy or being unwell, this must be discussed with your family doctor or specialist.
The benefit afforded by all the coronavirus vaccines so far has significantly outweighed any reported side effects. While lockdown measures, social distancing, mask wearing and hand hygiene measures all serve to protect us, vaccines are the only route we know as yet which may help ensure we can remove these measures and return to normality more quickly. It would be nice to think that Covid-19 will disappear but given what has happened over the last year and the 3rd waves that are now happening in parts of Europe such as Italy, we feel this is highly unlikely in the short to medium term.
All of this, we hope provides a measure of reassurance for APS patients who are concerned about the vaccine. As more data becomes available, we will update the advice.
