July 23, 2024

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Can the booster shot of COVID-19 vaccine really prevent infection?

Can the booster shot of COVID-19 vaccine really prevent infection?


Can the booster shot of COVID-19 vaccine really prevent infection?

The booster shot data of Moderna, Johnson & Johnson in place,  so Can the booster shot of COVID-19 vaccine really prevent infection? 


Booter shot data of Moderna, Johnson & Johnson in place

Pfizer’s COVID-19 booster shot (third dose) has been started in some people in the United States at the end of September. The booster shots of Moderna and Johnson & Johnson’s vaccines are naturally on the agenda.

FDA’s vaccine experts will discuss Moderna’s booster shot (third dose) on October 14 and Johnson & Johnson (second injection) on the 15th. The FDA also announced on October 12 the briefing documents of the two vaccine booster shots in advance.


Among them, Moderna includes a summary of the company’s application materials and FDA analysis. Johnson & Johnson only has a summary of the company’s application materials, and the FDA’s relevant analysis has not been updated. If nothing else, these two booster shots will be approved like Pfizer and will be officially recommended at the CDC meeting on October 20-21.


Applicable to the crowd, Moderna booster shots should be exactly the same as Pfizer. Previously, Moderna’s abacus was the same as that of Pfizer. It was half a year for all adults, but after Pfizer’s population was limited, the people applying for Moderna’s booster shot have also been confirmed as three groups of people over 65 years of age, high risk of severe illness, and high risk of infection.


Relatively speaking, there are certain variables in the application of Johnson & Johnson’s booster shot. It now has a two-dose phase III clinical trial result, which shows that two doses every two months have better protection than just one dose.

This is the fact that the effectiveness of the actual data is higher, not just more antibodies. Considering that the starting point of the effectiveness of this vaccine itself is lower than that of the two mRNA vaccines, it may become recommended that all Johnson & Johnson vaccines be given another shot.


Since the interval between two needles of Johnson & Johnson’s Phase III clinical trial is two months, the recommended interval is also questionable. Johnson & Johnson has application materials that show that the number of antibodies given for the second injection at half a year intervals has increased even more.

But a second shot every two months can already increase antibodies and improve effectiveness. For a vaccine with a lower effective starting point, should you wait longer in exchange for higher antibodies, or do you have to take the second shot as soon as possible to increase effectiveness? , Need to weigh and consider.

In addition, a clinical trial involving tens of thousands of people every two months has shown a real increase in effectiveness, and an experiment involving less than 20 people in half a year has higher antibodies. In terms of the sufficiency of the evidence, it seems that the two-month support is even higher.


Mashup variables


The biggest variable is mixed play. In the FDA meeting on 14-15, NIH will show the results of its mixed-beating test. In this trial, different vaccines were passed between mixed fights and the initial vaccination after an interval of 3-4 months.

Except for the half-year gap between the interval and the current discussion, the number of people in the whole trial was small, and the number of people in a mixed group was about 50. It is estimated that there will be some controversy about whether to recommend mixed play based on this amount of data.


In addition, in the NIH mixed-playing test, the dose used by Moderna was 100 micrograms, which was the same as the first two injections approved by Moderna. But now Moderna’s application for the booster needle dose is 50 micrograms, which is halved.

With such a dose adjustment, there are also questions about how the NIH mixed-beating test should guide the booster shot mixed-beating. If it is recommended to mix with booster shot, should Moderna use the 50 microgram half dose applied by Moderna itself? Or the full dose of 100 micrograms tested by NIH?


In fact, the United Kingdom and Canada have more practice and data on the issue of mixed fights. It may be more meaningful to refer to the research and experience of these countries.

Of course, it seems that the FDA is more willing to invite Israel to educate everyone on why it is important to enhance the needle.

After Pfizer’s enhanced acupuncture expert meeting was invited to attend a half-hour class, this time an Israeli expert was invited to attend a one-hour class.

The purpose of the course written by the FDA is “data related to the necessity of enhanced acupuncture.” Review whether the United States needs Moderna and Johnson & Johnson booster injections, and find a foreign country that only uses Pfizer vaccines to teach the necessity. As expected, never underestimate the Americans’ sense of humor.



171 people received booster shots, 18 people were infected with the COVID-19


Using this as the title of the article may brush some traffic? It’s a pity that I can’t pull my face down. However, in the trial of 171 people, 18 people were infected with the COVID-19 after the booster injection. This is indeed the most attractive data for me in the information released by the FDA.


These 171 people are not the Johnson & Johnson vaccine, which is considered to be of low effectiveness, but the booster shot test from Moderna, and they are the most critical research used by Moderna to apply for the booster shot.


Last time Pfizer applied for a booster injection, it took a 300-person immune bridging test, and it was questioned whether the number of people was too small.

Unexpectedly, there will be fewer now. However, this is indeed a key test for Moderna’s booster shot.

These 171 people received a half-dose booster shot of 50 micrograms about half a year after receiving two doses of 100 micrograms of Moderna vaccine.

In addition, 173 people received 50 micrograms for the first two injections.

However, due to the Phase III clinical trial of Moderna and the actual approved first two needles are both 100 micrograms, the latter 173 people have limited reference to the current booster shots.


After 171 people were vaccinated with the booster needle, a total of 18 cases of COVID-19 infection occurred. It should be noted that the COVID-19 infection is not the main research purpose of this test.

The booster needle test is to clarify the immune response, such as whether the antibody has increased and how much. Pfizer’s booster shot test did not detect infection at all. Moderna selected several time points for testing during the follow-up period.


Of the 18 confirmed infections, 16 were under 65 years old and 2 were over 65 years old. Two people were diagnosed 8 days after the booster injection, 1 person was diagnosed within 29 days, 14 people were diagnosed within two months, and one person was diagnosed nearly half a year after the booster injection. Only 1 out of 18 people had symptoms and no serious illnesses occurred.


Since there is no control group, the effectiveness of these infections cannot be estimated. But 171 people can have 18 cases of infection, and it should be possible to pour cold water on those who feel that the booster shot can solve the infection problem. Special attention should be paid to the fact that the vast majority of infections occurred two months before the completion of the injection, which should be the peak of the antibody of the booster shot. It can be seen that the antibody titer should not be blindly believed.


What do you think of so many infections in clinical trials of booster shots? There are still two points that are often said. First, correct the expectations of the vaccine, that is, understand the purpose of the vaccine, and second, pay attention to the impact of behavior and the environment.


Most of the 18 infections were asymptomatic. This may mean that the absolute protection of the vaccine, even with the booster needle, against infection is very difficult. This is in line with scientific principles. After all, infection takes a short time and protection is difficult. But the most basic and most important role of the COVID-19 vaccine is to prevent severe illness and death. The effectiveness of preventing mild illness or infection is lower, and it should not be said that the vaccine is ineffective.


Changes in human behavior and the external environment have a huge impact on the infection rate. Whether it is Moderna or Pfizer, they have conducted phase III clinical trials to compare the population who received the first vaccine after unblinding and the second vaccine. The infection rate of those who were first received (long vaccination time) was higher, but the biggest difference was actually the third phase. Phase clinical trials did not unblind time. The infection rate of the vaccine group without unblinding was much lower than after unblinding.


Why is this happening?

First, knowing that you have been vaccinated or not knowing whether you have been vaccinated or not, human behavior is likely to have huge changes. People with a sense of security dare to take risks.

Second, the environment has changed, and Delta has caused a sharp increase in the background infection rate in the United States.

In this case, there are more opportunities to be in close contact with the virus at any time, and even if the vaccine is vaccinated, the possibility of infection also increases.



Sum up:

The discussion of booster shots in United States is still chaotic. In fact, when discussing booster shot, we must first understand two issues. One is what the vaccine is expected to do, and the other is what the current vaccine can do.


If the expectation is to prevent severe illness, is the effect of the two injections now enough? If there is not enough, who is not enough? Can these people get a booster shot to solve the problem? It is entirely possible that some people will not solve the problem with ten or eight injections, such as immunosuppressed people. You can’t blindly think that one more shot is enough to protect these people. In particular, these people should not be allowed to feel a false sense of security.


If it is to prevent infection and prevent mild illness, can it be solved by intensified injections? The director of the CDC decided to allow people at risk of occupational exposure to get the third shot. One basic reason is that even infection can be prevented. How reliable is this idea? Similarly, don’t give people a false sense of security. Once you have a false sense of security, the subsequent changes in behavior may be more effective than booster shots.




Can the booster shot of COVID-19 vaccine really prevent infection?

(source:internet, reference only)

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