May 25, 2024

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Any risk of thrombosis on the mRNA vaccine?

Is there any risk of thrombosis in the mRNA vaccine?


Any risk of thrombosis on the mRNA vaccine?  On April 21, the European Drug Safety Supervision Committee held a press conference to provide the latest report on the thrombosis risk of Johnson & Johnson’s COVID-19  vaccine.

The Johnson & Johnson vaccine is not yet on the market in Europe, and all thrombus data comes from the United States. According to the latest data provided by the US FDA and CDC, a total of about 7.2 million people have received the Johnson & Johnson vaccine, and there are 8 cases of severe thrombosis associated with thrombocytopenia (name given by the World Health Organization, TTS for short), and 7 cases were discovered after the vaccine was launched. (6 cases were confirmed when Johnson & Johnson suspended, 1 case was under study, and this case is now confirmed), 1 case appeared in a clinical trial and is now confirmed retrospectively.

Because these cases are very similar in performance to the brain thrombosis cases that occurred before the AstraZeneca/Oxford University vaccine, the European drug regulatory agency decided that Johnson & Johnson vaccines also need to include this rare thrombosis in potential adverse reactions. Johnson & Johnson will also continue to follow up and investigate.

This decision is not unexpected. Although the number of rare thrombosis cases in Johnson & Johnson is much lower than the AstraZeneca/Oxford University vaccine in terms of total number (8 cases) and incidence (approximately one in a million) (more than 200 cases, the highest incidence is predicted to be 100,000 points) One), but after all, the symptoms of the cases are too similar-autoimmune antibody formation, thrombosis accompanied by thrombocytopenia, and the rare brain is mostly (CVST)-7 of Johnson & Johnson’s 8 cases have CVST. Too many similarities make regulators have to proceed with caution, especially both vaccines are adenovirus vaccines.

But in this one-hour press conference, what attracted my more attention was the number of similar thrombosis cases of the two mRNA vaccines. The number of rare thrombosis cases of the two adenovirus vaccines-specifically TTS, which is accompanied by a decrease in platelets, has been relatively consistent. However, the relevant data of the two mRNAs are different according to the published sources, and there are many contradictions.  This article will list these contradictions in detail based on European data.


The mystery of the number of thrombosis cases of mRNA vaccine

At the FDA and CDC press conference on April 13, apart from announcing that Johnson & Johnson had suspended six cases of rare brain thrombosis (all CVST), FDA officials in response to reporters emphasized that two mRNA vaccines were not found in the same category. thrombus. The data listed at that time are as follows:

Pfizer vaccinated more than 90 million shots in the United States and no CVST was found; Moderna vaccinated 80 million shots, 3 cases of CVST, but these 3 cases did not have thrombocytopenia, which is different from the two adenovirus vaccines. In other words, in the United States, the two mRNA vaccines did not have any rare thrombosis accompanied by thrombocytopenia-TTS as defined by the World Health Organization.

Note that the original source of these data is CDC’s VAERS, which is analyzed and sorted out. VAERS is a reporting system for adverse vaccine reactions in the United States. Anyone can report various situations that occur after vaccination as potential adverse reactions. Due to the freedom of initial reporting, a reliable conclusion must be analyzed by professionals.

But at today’s European press conference, the data involving two mRNA vaccines are as follows:

As of April 13, there were 25 cases of severe thrombosis (including CVST) associated with thrombocytopenia in Pfizer and 5 cases in Moderna.

These 25 cases and 5 cases were mentioned twice in the press conference. For the first time, it was not confirmed whether it was accompanied by the key feature of platelet decline, but when the reporter asked the details for the second time, it was confirmed that these also had platelet decline. In other words, the performance of these cases is consistent with the cases involving adenovirus vaccines.

In fact, when the thrombosis risk of the AstraZeneca/Oxford University vaccine was confirmed in Europe, the European regulatory authorities mentioned that as of April 4, Pfizer had 35 cases of CVST and Moderna had 5 cases, but this data was not mentioned at the time. The problem of thrombocytopenia. Considering that Pfizer’s cases have decreased this time, it can be corroborated that the characteristic of thrombocytopenia is indeed increased.

In any case, this data is obviously different from the data given by the FDA and CDC (the data given by Pfizer is not a single case).

In fact, before this, the Oxford University paper discussing the risk of CVST after the COVID-19 infection also indirectly conflicted with the FDA and CDC data. The pre-printed paper analyzed electronic medical records in the United States. Two cases of CVST were found among about 500,000 people who had received the mRNA COVID-19 vaccine. One case was vaccinated with Pfizer, and the other case was unknown.

Note that in the CDC data, Pfizer does not have 90 million needles of CVST in the United States. Here are 500,000 American electronic medical files. It is clear that a Pfizer vaccine recipient left a CVST hospitalization record within two weeks after vaccination. This is obviously inconsistent.


Differences in data sources?

One explanation for this conflict may be different data sources. As mentioned before, the data source of CDC is VAERS. This is based entirely on a database in the United States. Although the electronic medical archives used by Oxford University are also American, after all, the American medical system is extremely fragmented, and it cannot be ruled out that some records in the medical archives are not reflected on VAERS. But considering that VAERS may be the most liberal case collection system, this explanation is still far-fetched.

But this is only one case after all, and I don’t know whether it is accompanied by a decrease in platelets. But more puzzling is the data given by Europe.

The European data source is drug safety monitoring data from Europe, but this does not mean that these data only come from Europe, because it was also mentioned in the press conference that Europe requires pharmaceutical companies to report all adverse reactions collected globally. of. Therefore, these data should contain some cases outside of Europe, even if they are in the United States, if pharmaceutical companies are aware, they will be reported and included. In theory, even if it is not the same as the data given by CDC according to VAERS, it should not be so different.

In fact, at the press conference to confirm the risk of thrombosis of the AstraZeneca/Oxford University vaccine, 35 cases of CVST from Pfizer and 5 cases of CVST from Moderna were given. European officials clearly stated that these are global data.

Considering that the world that uses Pfizer and Moderna vaccine the most is the United States, especially Moderna, which was almost all bought out by the United States before. Only recently have other countries started to vaccinate this vaccine. It is hard to imagine that the 25 cases of Pfizer and the 5 cases of Moderna mentioned in Europe can all be outside the United States.

If it really comes from outside the United States, it will bring two more serious problems.

First, the United States is the most vaccinated with these two vaccines. If so many cases can be found outside the United States, regardless of whether it is related to the vaccine, even if it is caused by natural background, the United States should not have none of them. It is seriously doubted whether VAERS has major loopholes in the collection of thrombus cases.

Second, if it is true that all cases are non-U.S. cases, since the number of people vaccinated with these two vaccines outside the U.S. is not very large, the probability of thrombosis may be very high. Note that Johnson & Johnson is currently only one in a million. If Pfizer’s 25 and Moderna’s 5, the corresponding denominator does not have the population of vaccinated in the United States, I am afraid it will not be much lower than one part per million. Then it is very improper to completely exclude the risk of mRNA thrombosis.

In short, it is difficult to find a reasonable explanation for this statistical difference.


The importance of the number of cases

In the rare thrombosis problem of AstraZeneca/Oxford University vaccine and Johnson & Johnson vaccine, we most often emphasize the relevance to the vaccine and the analysis of benefits and risks. These are directly dependent on accurate and credible statistical data on adverse reactions.

Take the rare thrombosis associated with platelet decline as an example-that is, the recent CVST discussion, the highest incidence of AstraZeneca/Oxford University vaccine is expected to be one in 100,000, while Johnson & Johnson is currently one in a million (focused on Two weeks after vaccination). These are higher than the incidence rate in the natural context (the incidence of CVST itself is 3-15 cases per million people per year, which corresponds to 0.6 cases per million people in two weeks. The European press conference mentioned that the incidence of platelet decline may be due to this. 7% of the total)-This is an important basis for our belief that this adverse reaction is likely to be related to the vaccine.

In addition to the assumption that the adverse reactions are related to the vaccine, the incidence rate calculated by accurate statistics of the number of cases is directly related to how we conduct risk assessment and confirm that the benefits of the vaccine in the vaccinated person are indeed greater than the risk of the adverse reaction.

Nowadays, the statistics of thrombosis of mRNA vaccines are so different, how to make the correct risk-benefit judgment? Even what kind of data we are using to exclude the risk of thrombosis from mRNA vaccines have to be questioned.

It should be pointed out that even if the number of thrombosis cases of the mRNA vaccine is based on the highest value given in Europe, the incidence is still lower than the AstraZeneca/Oxford University vaccine (the vaccine currently has 287 cases recorded). Compared with the huge life and health risks brought by COVID-19, the benefits of AstraZeneca/Oxford University vaccines are far greater than the risks caused by thrombosis, and this is especially true for mRNA vaccines.

But not changing the final risk-return assessment result is not a reason to pull in the process. Just like Johnson & Johnson’s rare thrombosis risk, even if the incidence is only one in a million, single-digit cases must be analyzed case by case, and cannot be omitted. The same is true for mRNA vaccines, and such large statistics cannot be used as a basis for decision-making.



(source:internet, reference only)

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Important Note: The information provided is for informational purposes only and should not be considered as medical advice.