LONDON (Reuters) – There is a much higher risk of blood clots from COVID-19 infection than from vaccines against the disease, British researchers said on Thursday after a discontinuation of inoculation due to reports of rare clots .
AstraZeneca and Johnson & Johnson have seen very rare reports of cerebral venous sinus thrombosis related to their vaccines. On Wednesday, the United States stopped vaccinations with the J&J shot while investigating a clot link, and Denmark dropped the AstraZeneca shot on the subject.
British and European regulators have stressed that the benefits of vaccination outweigh the risks.
A study of 500,000 patients with COVID-19 found that CVST had occurred at a rate of 39 people over a million after infection, the researchers said. This compares with figures from the European Medicines Agency which shows that 5 out of every million people reported CVST after receiving AstraZeneca’s shot.
The researchers said in a pre-printed study that the risk of CVST was 8-10 times higher after COVID-19 infection than that of existing vaccines against the disease.
“The risk of having one (CVST) after COVID-19 appears to be substantially and significantly higher than that which occurs after receiving the Oxford-AstraZeneca vaccine,” Maxime Taquet of the Oxford Department of Psychiatry told reporters.
The study was based on a U.S. health database and therefore did not accumulate new data on the risk of clots from the AstraZeneca vaccine directly, as the shot is not developing there.
Taquet said the CVST mortality rate was around 20% whether it occurred after COVID-19 infection or was vaccinated, indicating that clots were the main risk factor.
A new Oxford study shows that the risk of rare blood clotting (CVD) is higher after contracting # COVID-19[FEMININE del que és postvacunació.
La TVC també és 100 vegades més probable que es produeixi després del COVID-19 del normal.
Més informació ⬇️ https://t.co/bVUxemNpxQ
– Universitat d’Oxford (@UniofOxford) 15 d’abril de 2021
Els reguladors també havien observat nivells baixos de plaquetes en els informes d’efectes secundaris de la vacuna, però els investigadors van dir que les dades eren limitades sobre si aquest també era el cas en aquells que van informar CVST després de la infecció.
Els investigadors van destacar que el COVID-19 es va associar amb trastorns de coagulació més comuns que el CVST, com ara els ictus, i que el debat recent sobre les vacunes havia perdut de vista la gravetat de la malaltia.
“La importància d’aquest descobriment és que el torna al fet que es tracta d’una malaltia realment horrible, ja que hi ha una gran varietat d’efectes, incloent un augment del risc (CVST)”, va dir John Geddes, director del NIHR Oxford Health Biomedical Research Center
L’equip d’investigació, de la Universitat d’Oxford, va dir que treballava independentment de l’equip de vacunes d’Oxford que va desenvolupar el tret d’AstraZeneca.
(Informe d’Alistair Smout; Edició de Bernadette Baum)
© Copyright Thomson Reuters 2021