AstraZeneca's new crown vaccine is linked to slightly increased risk of bleeding disorders

At the time of the global pandemic of the new crown, vaccines are being placed with high hopes of restarting the world
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At 23:00 on June 9th, Beijing time, the top international academic journal "Nature Medicine" (Nature Medicine) published online a study completed by the British team, entitled "First-dose ChAdOx1 and BNT162b2 COVID-19 vaccines and thrombocytopenic" , thromboembolic and hemorrhagic events in Scotland"
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Investigations have shown that the Oxford-AstraZeneca vaccine is associated with a slightly increased risk of an autoimmune hemorrhagic disease, immune thrombocytopenic purpura (ITP)
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The British team emphasized that public health authorities should inform their jurisdictions of these relatively small increases in risks associated with ChAdOx1
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"Nature-Medical" also published opinion articles written by Douglas B.
Cines of the University of Pennsylvania in the same journal
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1.
13 out of every 100,000 injections of the first dose

The paper writes that the three vaccines currently used in the UK are the Oxford-AstraZeneca new crown vaccine ChAdOx1, Pfizer-BioNTech's new crown vaccine BNT162b2 and Moderna's mRNA-1273, all of which have been proven to reduce COVID-19 infection
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Previous clinical trials have shown that the two vaccines ChAdOx1 and BNT162b2 for the new coronavirus are generally well tolerated, but there are a few reports of serious side effects
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The European Medicines Agency also listed thrombosis with thrombocytopenia as a rare side effect of the AstraZeneca vaccine in April, but still believes that the benefits of vaccination outweigh the risks, and EU member states decide whether to continue using it
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In order to investigate the possibility that the new crown vaccine is related to the progression of blood diseases, Aziz Sheikh and colleagues at the University of Edinburgh in the United Kingdom investigated the first dose of the new crown vaccine between December 2020 and April 2021 (the most common ones are ChAdOx1 or BNT162b2).
) 2.
53 million Scottish adults (57% of the adult population over the age of 18) were associated with vaccine-related bleeding and vascular events
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The research team found that in the survey population, ChAdOx1 vaccine was associated with a slight increase in ITP risk for up to 27 days after injection.
The disease caused slight bruising and excessive bleeding in some patients, and some patients developed chronic diseases
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The analysis also showed that within 27 days of ChAdOx1 injection, there was a slight increase in the risk of other arterial thrombosis and bleeding events
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However, there is insufficient evidence that ChAdOx1 is related to cerebral venous sinus thrombosis (a rare disease that forms a blood clot in the brain)
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At the same time, the research team found no evidence that the BNT162b2 vaccine is associated with an increased risk of these adverse events
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In the paper, the research team pointed out several limitations that should be paid attention to
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Since few people received two doses of vaccine at the time of analysis, this subgroup (second dose) was not investigated separately, and the second dose will be further analyzed in due course
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In addition, there are fewer young vaccinators (<40 years old) in this study, especially the ChAdOx1 vaccine, because the vaccination program has so far mainly prioritized older groups and groups with underlying underlying diseases
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They pointed out that further research needs to include younger people and assess the response to the second dose of the vaccine
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Limitations also include the need for the study to assume that clinicians have properly investigated the patient's thrombocytopenia before recording the diagnosis of ITP
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The research team concluded that in patients who received the BNT162b2 vaccination, they did not find any increase in the overall risk of adverse events
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The first dose of ChAdOx1 was associated with a slight increase in the risk of ITP, suggesting an increased risk of arterial thromboembolism and hemorrhagic events
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In view of the slight increase in these risks of ChAdOx1, the study believes that if the supply of the new crown vaccine is sufficient, it may be necessary to provide the public with other alternative vaccines
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"The balance between risk and benefit"

The research team also emphasized that the benefits of ChAdOx1 are very clear, and these findings should be understood in this context
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The risk of serious adverse events caused by the vaccine is much lower than the risk of severe illness or death caused by new coronary pneumonia, especially for the elderly and other vulnerable groups
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The research team said that it should be noted that these small risks are important but rare, and are comparable to the risks of other vaccines, including vaccines for hepatitis B, cysticercosis, mumps, rubella, and influenza
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Cines and others also wrote in their opinion article that the world's efforts to control the new coronavirus have brought the fastest and most extensive vaccination plan in human history
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Despite its many benefits, it also has potential side effects, including autoimmune reactions
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Cines et al.
emphasized that when interpreting the findings in the latest study published by Nature-Medicine, it is necessary not only to consider the advantages and limitations of the research itself, but also to consider the broader clinical background and the risks and benefits of vaccination.
The balance between the two is very important
.
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This opinion article believes that, in general, the idea that vaccination may induce immune thrombocytopenic purpura is not new, and it is not without precedent in the history of vaccines
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For example, thrombocytopenia is common in children who receive an attenuated measles vaccine
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The risk of ITP is generally mild and will subside within a few weeks or months.
It is estimated that about 1 case per 40,000 doses of measles-mumps-rubella vaccine, which is only slightly higher than the risk of natural infection
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Cines et al.
believe that attributing a rare adverse event to a vaccine will exacerbate the phenomenon of "vaccine hesitation" and have an important impact on public health
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"In general, the authors concluded that there is no clear evidence that ITP is related to the first dose of the BNT162b2 vaccine, and the ChAdOx1 vaccine may increase the risk of ITP
.
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They believe that, at present, the incidence, severity, duration, and response to treatment of ITP after vaccination have not yet been fully determined, and further analysis is needed
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"Nevertheless, the risk of vaccine-induced ITP appears to be much lower than many of the risks associated with COVID-19
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Cines and others pointed out that some large international efforts are still ongoing to continue to evaluate and improve vaccine safety
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Link to the paper: https:// href="/news/sub2.
aspx?id=3570" target="_blank" style="color:#ba1413">Focus on the new crown pneumonia epidemic