Filenews 10 June 2021
Slightly increased is the risk for an autoimmune hemorrhagic disorder, the idiopathic thrombocytopenic purpura, associated with the Oxford/AstraZeneca vaccine, British scientists have announced. The probability of developing the disorder was recorded up to the 27th day after vaccination and its frequency was 1.13 cases of autoimmune thrombocytopenia or thrombocytopenic purpura per 100,000 first doses of vaccine.
The finding was based on analysis of data on 2.53 million adults in Scotland (57% of residents over the age of 18) who had the first dose of either Oxford/AstraZeneca or Pfizer/BioNTech between December 2020 and April 2021. Idiopathic thrombocytopenic purpura can cause from small skin ectyms ("bruises" due to hematoma) in some patients to more severe bleeding in others.
The researchers, led by Dr Aziz Sheikh of the University of Edinburgh, who published the study in the medical journal Nature Medicine and also held a press conference, said there was potential evidence of an increased risk of other bleeding and vascular events associated with the Oxford/AstraZeneca vaccine, also up to the 27th day after vaccination. Insufficient evidence was considered to conclude that this vaccine is associated with rare cerebral thrombosis.
As scientists have said, however, these are very small and rare risks, comparable to those from other vaccines, such as hepatitis B, measles-mumps-rubella and influenza. On the other hand, they noted that they found no evidence of an increased risk for such episodes associated with the Pfizer/BioNTech vaccine.
In any case, the researchers pointed out that their findings need to be understood within the broader context of the very clear benefits of the Oxford/AstraZeneca vaccine, in terms of the protection it provides from coronavirus. They stressed that the risk of developing a serious side effect is much lower than the risk of severe disease and death due to Covid-19, especially for the elderly and other vulnerable groups. They also stressed the need for further research in younger people under 40 years of age in order to better assess the body's reaction to vaccinated after the second dose.
Health authorities in Britain have so far reported 209 thrombocytopenic and thromboembolic cases (bleeding and thrombosis disorders respectively) after approximately 22 million first doses and 6.8 million second doses of the Oxford/AstraZeneca vaccine.
