New Pfizer Vaccine Publications Show High Efficacy And Potential Unusual Undesirable Effects

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New Pfizer Vaccine Publications Show High Efficacy And Potential Unusual Undesirable Effects
New Pfizer Vaccine Publications Show High Efficacy And Potential Unusual Undesirable Effects
Anonim

The developers of the American-German vaccine published the results of its clinical trials in a scientific journal - and they showed good efficacy. At the same time, the American Food and Drug Administration (FDA) published a document: according to it, some of those vaccinated with this vaccine received temporary paralysis of a part of their face (Bell's palsy), which, however, quickly passed from them.

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The peer-reviewed scientific journal The New England Journal of Medicine published an article on the results of the third phase of clinical trials of the BNT162b2 vaccine (also known as "tocinameran", and in everyday life - the "Pfizer vaccine"). Its results are quite optimistic: the average efficiency of Covid-19 prevention, according to the diagnostic method used in the study, was 95%. Below we will explain why this technique raises some questions.

What is this vaccine

It should be noted that although the drug is called “Pfizer's vaccine,” this is technically incorrect. Pfizer is an American company, and BNT162b2 itself was created by the German startup BioNTech, headed by two German citizens (husband and wife) who are ethnic Turks. Pfizer is in this connection responsible for mass production and marketing, not development.

Until 2020, BioNTech has never dealt with vaccines against infectious diseases. The mRNA vaccines he created - that is, based on messenger RNA (the RNA used to synthesize protein) - were originally intended for anti-cancer therapy. However, in this sector of mRNA vaccines have not yet succeeded (anti-cancer therapy is generally extremely difficult).

BNT162b2 creates immunity from coronavirus due to the fact that it contains lipid (fat) nanoparticles, inside which there is mRNA. When it enters a human cell, this mRNA encodes the S-protein of the coronavirus in it. The protein enters the bloodstream, where the cells of the immune system learn to attack its molecules. If a person then becomes infected with a complete coronavirus, he will also be neutralized by the immune system, since the envelope of the coronavirus consists of this protein.

Due to the great technical novelty, they would not have dared to use such a vaccine platform for the prevention of infectious diseases for a long time, but in the critical conditions of 2020, the situation has changed markedly - and Western regulators (Great Britain, Canada) allowed BNT162b2 to be inoculated on December 1, even before the publication of the results of clinical trials vaccines in a scientific journal.

On December 10, such a publication finally appeared - and this is extremely important: the US Food and Drug Administration (FDA) is holding a meeting today about the emergency approval of this vaccine for use in the States.

Clinical trial results: pros and cons

A total of 43,548 people participated in the third phase, according to an article in The New England Journal of Medicine, of whom half received the BNT162b2 vaccine and the rest received a placebo. On the 28th day after the first dose of the vaccine and in the period from the seventh day after the second dose of Covid-19, nine people from the vaccinated group and 172 people from the placebo group fell ill. The average effectiveness of the drug is 94.8%.True, after the first dose, but before the second, the efficiency was 52.4% (the interval between doses was 21 days, like in the Russian "Sputnik-V"), and after the second - 90.5%. Such a difference is expected: the full formation of immunity takes about a week after the second vaccination.

To find out the effectiveness of the vaccine, the organizers of the study counted those who fell ill with Covid-19 using a special method: those who complained about coronavirus symptoms were sent for a PCR test. If it turned out to be positive, the person was recognized as infected with the coronavirus, and if not, they were not recognized.

This is a rather controversial technique, since it is well known that most of the Covid-19 diseases are asymptomatic. Moreover, if PCR testing is carried out with a delay and the virus has already "descended" below the upper respiratory tract, into the lungs, then the tests may not show anything, even if the person has signs of the disease.

Suspicions of this kind are further reinforced by the fact that, according to the article on the results of clinical trials, 1594 people among the vaccinated group and 1816 people among those who received a placebo during the tests showed symptoms similar to coronavirus. Since the size of both groups was similar, it is highly doubtful that those who received the placebo accidentally showed such symptoms 13.9% more often than those who received the vaccine. Most likely, some of the "symptoms" simply fell ill with Covid-19, which they did not have time to diagnose with a PCR test.

From the experience of the participants in the clinical trials of the Pfizer vaccine, it is known that no continuous monitoring by PCR tests, as in the case of the Oxford and AstraZeneca vaccine trials, was organized there. Therefore, it was relatively easy to miss a sick person.

At the same time, such a shortcoming in the organization of clinical trials of an mRNA vaccine can hardly be called too critical. Obviously, the effectiveness of preventing symptomatic cases of the disease is extremely high - about 95%. Almost all severe cases during the trial were in the placebo group. Only one of those vaccinated showed a severe form of Covid-19, but he contracted before the second dose of the vaccine, that is, even before the full formation of immunity.

All this means that the BNT162b2 is definitely effective. This is important, since it is with her that they will begin to inoculate in the West. The Oxford vector vaccine AstraZeneca is unlikely to receive regulatory approval any time soon, as its efficacy averaged 70.4% - much lower than the other coronavirus vector vaccine.

What's with the safety of "Pfizer vaccine"

The new article shows that 59% of young (up to 55 years old) vaccinated in the first days after vaccination complained of fatigue, 52% of headaches. Among those who were over 55 years old, 51% complained of fatigue, and 39% of headaches. From this it would appear that the incidence of adverse events was less common among the elderly than among the younger. However, a closer look at the numbers shows that things could be very different.

It should be understood that due to the widespread misconceptions about vaccines in society, some of these complaints could be a purely psychological phenomenon. For example, among those who received a placebo under 55 years of age, 23% and 24% complained of fatigue and headache, respectively. Perhaps the older generation is mentally less susceptible to such moods: in people over 55 years old in the placebo group, 17% of participants complained of fatigue, and only 14% complained of headaches.

The reason may be that people over 55 were educated and formed as individuals in another era - when anti-vaccination sentiments were less popular. Therefore, it is possible that similar complaints among vaccinated people are more common among the young than among the elderly, since the young are more likely to expect such sensations from vaccination. And therefore they can “feel” them even without any objective grounds.

At the same time, it cannot be denied that in some cases the undesirable phenomena were quite real.3, 8% of those who received the second dose of the vaccine complained of severe fatigue, another 2, 0% of severe headache.

Even more important are the quantifiable signs of adverse events. Temperatures ≥38 ° C after the second dose were shown by 16% of those vaccinated under the age of 55 and 11% of those vaccinated over the age of 55. The latter is understandable: the strength of the immune system decreases with age, therefore, an increase in temperature - one of the immune reactions - in the elderly may also be weaker.

0.2% of those vaccinated after the first dose of the vaccine had a serious fever - from 38.9 to 40 ° C. In the placebo group, such immediately after the first injection was 0.1%. After the second dose among the vaccine group, this temperature was shown by 0.8%, and among those who received a placebo - the same 0.1%. Two vaccinated subjects had a temperature higher than 40 ° C, as did two people in the placebo group. Therefore, it is difficult to say how much such a high temperature could be associated with vaccination, and not with other factors.

To understand how common adverse events are after a new mRNA vaccine, it is worth comparing them with adverse events following the AstraZeneca vectored vaccine. There, tens of percent experienced pain at the injection point and general weakness, 60% of those who received the vaccine experienced muscle pain, 61% reported general mild illness, 56% reported chills, 51% fever, and 18% of volunteers who did not take antipyretic showed temperature at least 38 ° C, 2% - 39 ° C and above. It follows from this that the overall incidence of adverse events in the mRNA vaccine does not significantly differ from the same incidence in the vector preparation.

What the scientific work kept silent about

In the text of the article, nowhere is there any explicit mention of cases of Bell's palsy in a number of participants. Meanwhile, in the document of the American Food and Drug Administration it is mentioned (p. 6 and others) that among almost 20 thousand vaccinated four received Bell's palsy, and there were zero such people in the placebo group. The likelihood that this is a coincidence is low.

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Bell's palsy is a complete or partial paralysis of the facial nerve that almost always goes away with time. In the case of four trial participants, they all got rid of such paralysis in a period of three days to three weeks. However, the case, which lasts three weeks, has not yet been fully completed, according to the latest data available to the FDA. However, with a high probability, the paralysis will also disappear in this fourth volunteer, since it is practically never permanent.

The real causes of Bell's palsy are not yet clear to science, although it is known that it most often occurs after hypothermia or colds. Until now, no such consequences have been known for any coronavirus vaccine.

What follows from this

The BNT162b2 mRNA vaccine appears to be effective and generally safe, with the possible exception of Bell's palsy. However, the latter itself does not last long and so far can hardly be recognized as a serious cause for concern. Consequently, Western states have allowed for emergency use of a completely complete vaccine, which makes it possible to hope to stop the coronavirus pandemic. The earlier suggestions that the mRNA vaccine will have too high reactogenicity (cause too acute undesirable effects), today look poorly founded.

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