January 21, 2022

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COVID-19 Vaccine: What effective data are correct?

ThCOVID-19 Vaccine: What effective data are correct?



COVID-19 Vaccine: What effective data are correct? Recently, the protection rates of COVID-19 vaccines from various manufacturers have been unveiled one after another. Not only are the protection rates of different manufacturers’ vaccines different, some vaccines from the same manufacturer have different protection rates at different times and regions, making the public confused. With so many protection rate data, which one is more scientific and accurate, and who should I listen to? Let me give you a detailed science popularization.

COVID-19 Vaccine: What effective data are correct?


1. The effective rate of the vaccine comes from a large amount of clinical data in Phase III, which is an indicator of herd immunity

The protection rate of the vaccine is the conclusion drawn in Phase III clinical trials, and it is also the most critical link before the vaccine is officially marketed to the public. In order to ensure the reliability and accuracy of the vaccine effectiveness data, a large amount of data is required for phase III clinical trials.

For example, if a certain vaccine is infected with only 1 out of 100 people after vaccination, if 10 people are enrolled in a clinical trial, the number of infections may be “zero”, can it mean that the effective rate is 100%? If there is exactly one infected person among 10 people, the effectiveness of the same vaccine will vary greatly.

Therefore, phase III clinical trials require huge experimental data. The COVID-19 inactivated vaccine currently used in China has enrolled more than 60,000 volunteers in the third phase of overseas clinical trials, and the coverage of the population is the first in the world.

It can be seen that the protection rate of the vaccine is data in the sense of a group and does not represent the effect of the vaccine on individuals.
To understand the meaning of the protection rate of a vaccine, we must also understand how the protection rate of a vaccine is calculated?


2. How to calculate the vaccine protection rate

A large amount of data is needed for Phase III clinical trials. Let’s take 10,000 in the experimental group and 10,000 in the placebo group as examples. The two groups were exposed to the environment that may be infected with the new coronavirus together when they were double-blind (that is, everyone did not know whether they were vaccinated or a placebo). As a result, 5,000 of the placebo-vaccinated volunteers were infected with the virus, and 500 of the vaccinated volunteers were infected with the virus.

Then, the protection rate of the vaccine is: 90% = (5000-500)/5000. This means that after vaccination, the risk of infection can be reduced by 90% compared to people who have not been vaccinated. The higher the protection rate, the better the protection effect, whether for groups or individuals.


3. Different times, regions, target groups, etc., lead to differences in vaccine effectiveness

The effective rate of China’s COVID-19 inactivated vaccine announced in the UAE and Bahrain is 86%. The effective rate announced in China is 79.34%. The reason for the discrepancy in data is that the Phase III clinical trial of the COVID-19 inactivated vaccine is a multi-center clinical trial carried out in multiple countries around the world. Each country has certain differences in case diagnosis standards and procedures, and the final results obtained will also be different. same.

In addition, the COVID-19 inactivated vaccine developed by Beijing Kexing Zhongwei Biotechnology Co., Ltd. (CoronaVac), Brazil announced in the early morning of January 13 that the overall effective rate was 50.38%; and on January 7, Zeng The effective rate of the vaccine is 77.96%; the effective rate of the vaccine is 100% for moderate and severe patients. The same clinical trial has successively obtained different effective rate values ​​because of the different statistical standards.

Relevant experts in Brazil pointed out that these different data sources are because the study divided patients diagnosed with new coronavirus pneumonia into mild, moderate, and severe symptoms. Only when the statistics are moderate and severe, the effective rate of the vaccine is 100% (that is, patients are Placebo group). In other words, if you are infected with the new coronavirus after being vaccinated with the COVID-19 vaccine, it will not develop into a moderate or severe case.

If the scope of statistics is expanded to include patients who need medical help and hospitalization, the clinical effective rate is calculated to be 77.96%. Continue to expand the scope and include patients with new coronavirus pneumonia with mild symptoms and not seeking medical help into the final result, and the overall effective rate is 50.38%. It can be seen that different effective protection rates are data analyzed and calculated from different dimensions.

In addition to Brazil, there is a big gap in the data of Phase III clinical trials of Beijing Kexing’s COVID-19vaccine in other countries. The effective rate in Turkey is 91.25%, and the effective rate in Indonesia is 65.3%. Which is more scientific and worthy of reference? Perhaps further observation data is needed.


4. The true meaning of vaccine protection rate

At present, the protective effect of China’s COVID-19 inactivated vaccine is 79.34%. Although some people will still get sick after vaccination, this is not to say that it is meaningless for these people to get the COVID-19 vaccine. Because it still has potential benefits for individuals, it can reduce the severity of these people’s illnesses. That is, if you are infected with the COVID-19 virus after vaccination, your condition is mild and you do not need to be hospitalized, or will not develop into a bad outcome such as severe illness.

Life is only once for everyone, and the value and significance of the COVID-19 vaccine are unmatched by other drugs and treatments.


(source:internet, reference only)

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