AstraZeneca covid vaccine is associated with a slightly increased risk of hemorrhagic disease

The new crown is in the global pandemic, and vaccines are expected to restart the world. However, reports of thrombocytopenia and adverse events related to the Oxford AstraZeneca new crown vaccine, cdadox1, have led to restrictions on their use in some countries, while reducing the enthusiasm of some public vaccinations to some extent.
At 23:00 p.m. on June 9, Beijing time, a study by the British team was published online by the international top academic journal Nature Medicine entitled “first dose cadadox1 and bnt162b2 covid-19 vaccines and thrombocytopenic, thromboembolis and hmorrhagic events in Scotland”. The study conducted a national survey of more than 2.5 million Scottish adults who had received the first dose of Oxford AstraZeneca new crown vaccine, chudox1 or Pfizer biontech new crown vaccine bnt162b2. The survey showed that oxfordiicon vaccine was associated with a slight increase in the risk of an autoimmune haemorrhagic disease, i.e. Immunet thrombocytopenic purpura (ITP). The study also found that there may be evidence that Oxfam AstraZeneca vaccine is associated with increased risk of other bleeding and vascular problems.
The UK team stressed that public health authorities should inform their jurisdictions of these relatively small risk increases associated with the chdox1“ If the new crown vaccine is adequately supplied, it may be necessary to provide the public with alternative vaccines. ”
Nature medicine also published with the journal opinion articles written by Douglas B. cines, et al. Of the University of Pennsylvania. Cines et al. Stressed that it is important not only to consider the strengths and limitations of the study itself in interpreting the findings of this newly published study, “but also to consider a broader clinical background and the balance between the risks and benefits of vaccination.”
1.13 cases were given the first dose of every 100000 cases
The three vaccines currently used in the UK are Oxford AstraZeneca new crown vaccine, cdadox1, Pfizer biotech new crown vaccine bnt162b2 and Moderna company mrna-1273, which have been shown to reduce covid-19 infection. Given that the first mrna-1273 was only conducted in Scotland on April 7, 2021, the study focused on chdox1 and bnt162b2.
Previous clinical trials have shown that the two vaccines against COVID-19, ChAdOx1 and BNT162b2, are generally well tolerated, but a few serious side effects are reported. After 22million first and 6.8 million second injections, the British drug and health care products Administration (MHRA) received 209 cases of thrombocytopenic purpura and thromboembolism (haemorrhagic and thromboembolism, respectively).
The European drug administration also listed thrombocytopenia with thrombocytopenia as a rare side effect of the AstraZeneca vaccine in April, but still found that the benefits of vaccination were greater than the risk, and EU Member States decided whether to continue using it.
To investigate the possibility of a new crown vaccine and the progression of blood diseases, Aziz Sheikh and colleagues from the University of Edinburgh, UK, investigated vaccine related bleeding and vascular events in Scotland (57 per cent of adults over 18) who received the first new crown vaccine (most commonly, chdox1 or bnt162b2) between december2020 and April 2021.
The team found that in the survey population, the cdadox1 vaccine was associated with a slight increase in ITP risk for up to 27 days after injection, which led to mild cyanosis and excessive bleeding in some patients, and chronic disease in some patients. It is estimated that 1.13 of every 100000 first dose injections occur.
The analysis also showed that the risk of other arterial thrombosis and bleeding events increased slightly within 27 days of the treatment with chdox1. But there is no sufficient evidence that chadox1 is associated with a cerebral venous sinus thrombosis, a rare disease that forms thrombosis in the brain.
At the same time, the team did not find evidence that bnt162b2 vaccine was associated with the increased risk of these adverse events.
The research team points out in the paper that several limitations of the study should be paid attention to. Since few people were vaccinated with two doses at the time of analysis, no separate investigation was conducted on this subgroup (second dose), and further analysis of the second dose would be carried out at the appropriate time.
In addition, the study had fewer young vaccinations (< 40 years old), especially the cdadox1 vaccine, because the vaccination program has so far given priority to older and potentially basic disease groups. They noted that further research needs to be included in younger populations and to assess responses to a second dose of vaccine.
Limitations also include the need to assume that clinicians have conducted appropriate investigations of thrombocytopenia before recording ITP diagnosis.
The team concluded that in patients vaccinated with bnt162b2, they did not find an increase in the overall risk of any adverse events. The first dose of chdox1 was associated with a slight increase in ITP risk, suggesting an increased risk of arterial thromboembolism and bleeding events.
Given the slight increase in these risks in chdox1, the study believes that it may be necessary to provide the public with alternative vaccines if the new crown vaccine is adequately supplied.
The “balance between risk and benefit” team also stressed that the benefits of chadox1 are very clear and should be understood in this context. The novel coronavirus pneumonia risk is far less than that of the new crown pneumonia, especially for the elderly and other vulnerable groups.
The team said it is important to note that these small risks are important but rare, and are comparable to those of other vaccines, including hepatitis B, cysticercosis, mumps, rubella and influenza.
Cines and others wrote in the opinion article that the world has brought the fastest and the most extensive vaccination program in human history to control COVID-19’s efforts. Despite its many advantages, it has potential side effects, including autoimmune responses.
Cines et al. Stressed that it is important not only to consider the strengths and limitations of the study itself when interpreting the findings of the latest study published in nature medicine, “but also to consider a broader clinical background and the balance between the risks and benefits of vaccination.”
This article holds that, in general, the view that vaccination may induce immune thrombocytopenic purpura is not new and there is no precedent in the history of vaccine. For example, thrombocytopenia is common in children vaccinated against measles. The risk of ITP is generally mild and will subside in a few weeks or months. It is estimated that one case is found in every 40000 doses of measles mumps rubella vaccine, which is only slightly higher than that after natural infection.
Cines et al. Believes that the attribution of a rare adverse event to the vaccine will aggravate the phenomenon of “vaccine hesitation” and have an important impact on public health“ Overall, the author concludes that there is no clear evidence that ITP is associated with the first dose of bnt162b2 vaccine, and that the chadox1 vaccine may increase the risk of ITP. ”
They believe that the incidence rate, severity, duration and responsiveness of ITP after vaccination are not yet fully defined and need further analysis. Nevertheless, the risk of vaccine induced ITP seems to be far lower than many of the risks associated with covid-19. ”
Cines et al. Noted that some major international efforts are still ongoing to continue to assess and improve vaccine safety.

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