New NICE Guidelines on Post-COVID Vaccine Blood Clots

Peter Russell

July 29, 2021

The National Institute for Health and Care Excellence (NICE) has published guidelines for diagnosing and treating vaccine-induced immune thrombocytopenia and thrombosis (VITT) after receiving COVID-19 vaccinations.

Despite being an extremely rare condition, with only 14.2 cases occurring per million doses of a COVID vaccine, NICE acknowledged that the condition can be very serious and required swift diagnosis and urgent treatment.

It said the rapid guidance could be updated as new evidence emerged about the link between VITT and COVID vaccination.

However, NICE stressed that it was not in its remit to pass any judgement on the safety of COVID vaccines.

The new guidelines outline how to identify people with suspected VITT, tests to confirm the condition, and treatment options depending on how serious their syndrome is and how their symptoms react to treatment.

Main Recommendations

In brief, the guidance recommends that:

  • Healthcare staff refer people with suspected VITT who are acutely unwell to the emergency department immediately

  • For patients who are not acutely unwell and where test results can be obtained and reviewed on the same day, a full blood count should be performed in primary care, and same day referral to the emergency department made in cases of low platelet count

  • Healthcare professionals should provide advice on the signs and symptoms of VITT in cases where blood tests indicate the syndrome is unlikely, and advise patients when and where to seek medical attention if symptoms persist or worsen

  • In cases where a high clinical suspicion of VITT remain, medical staff should consider repeating the full blood count after 2 to 3 days if symptoms worsen, or discuss further tests with a clinical haematologist

A diagnosis of VITT is confirmed by an enzyme-linked immunosorbent assay (ELISA). However, in cases where healthcare professionals suspect VITT, treatment should commence in consultation with a haematologist without waiting for ELISA results, the NICE guidance said.

For patients who have developed thrombosis, health professionals should perform same-day imaging tests such as a CT scan to confirm location of the blood clot before starting treatment.

Treatment options should include non-heparin anticoagulation drugs and surgical interventions to treat thrombosis. Patients should also initially receive intravenous immunoglobulin to treat the VITT immune response. A haematologist should be involved in decisions to start or stop treatments.

Healthcare Staff 'Need Support'

Dr Paul Chrisp, director of NICE’s Centre for Guidelines, said: "Although VITT is a very rare condition, it's crucial that healthcare professionals feel supported and able to swiftly identify and treat the small number of people who do develop it.

"This is a living guideline, which can be continuously updated to incorporate the latest evidence and keep abreast of new developments.

"This guideline has not looked at the safety of COVID-19 vaccines; that is not NICE's remit, and the data from the MHRA shows the benefits of COVID vaccines far outweigh the risks.

"NICE's role here is to provide the best advice to help clinicians treat patients in the rare instances where they do develop VITT."


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