How to choose a vaccine? AZ or Modena? Explore the secret of vaccine protection rate!

Halfway through 2021, but the epidemic is still raging. At this time, the focus of public attention is naturally on the “vaccine.”Before discussing what vaccine to administer, we want to discuss a question that has puzzled everyone for a long time. Is a vaccine with higher protection better?

There are four familiar vaccines, namely BNT, Modena, AZ, and Johnson & Johnson. According to the published data, the protection rates of the four vaccines are 95%, 94%, 70%, 66%, respectively.

So does this mean that BNT is the best and Johnson & Johnson the worst? In fact, the quality of a vaccine is not judged in this way, and the protection rate is not as simple as we have seen. So the first thing we have to figure out is how the vaccine calculates the protection rate?

How the vaccine protection rate is calculated?

The protection rate calculation method of any vaccine is calculated through large-scale clinical trials. The testing unit will recruit tens of thousands of people for testing to ensure the accuracy of the experiment. The test method divides the subjects into two groups, one group is given the vaccine, and the other group is given a placebo that does not affect. The subjects did not know which group they were given, and all subjects were told that the vaccine was effective.

Then all the subjects returned to their normal lives and continued to track whether they were infected with Covid-19. Take the current vaccine BNT with the highest protection rate as an example. Among the 43,000 participants, 170 people were infected with Covid-19. The ratio of these 170 people who fell in the vaccine group to the placebo group is to judge the vaccine’s protection rate.

If these 170 people are equally divided into two groups, it means that the vaccine’s protection rate is 0%, and it is the same whether it is given or not. Conversely, if these 170 people fall into the placebo group, the protection rate of this vaccine is 100%, and the final confirmed number of people in the vaccine group in this trial is 8 people, so the protection rate is 95%.

Protection rate Overall percentage

The BNT vaccine has a 95% protection rate, which means that there are only 5 confirmed cases for every 100 people who are given the BNT vaccine. And the Jiaosheng vaccine with a protection rate of only 66% means that there are 66 confirmed cases per 100 people?

This is a completely wrong idea. The percentage of protection rate does not refer to the whole but the individual. In other words, it means that after people are given the BNT vaccine, they have a 95% chance that they will not be diagnosed. Although the calculation method of each vaccine is the same, the environment of each clinical trial is different.

Deborah Fuller, professor of microbiology at the University of Washington, said, “So when we look at these data, the most important thing to look at is the timing of these clinical trials.”

This is the distribution map of the number of people diagnosed in the United States during this epidemic.

The BNT and Monad vaccines were completed in August-November 2020, which was the early stage of the outbreak in the United States. However, the time for Johnson & Johnson to conduct large-scale clinical trials is from October 2020 to November 2021, when the vaccine infection peaks. That is to say, at the time when Johnson & Johnson conducted the test, it was originally an environment in which all subjects had an increased risk of infection.

Johns Hopkins University Health and Safety Senior Scholar Amesh Adalja said, “If we really want to make a positive comparison between the two vaccines, they must conduct clinical trials at the same time and region and use the same harvest standard, so if we retest the BNT and Modena vaccines at the time when Johnson & Johnson is conducting clinical trials, the results may be completely different.”

The purpose of the vaccine

In addition, many experts suggest that the public should not simply evaluate vaccines based on the protection rate. After all, the purpose of vaccines is not to completely prevent infection.

Amesh Adalja said in an interview that “the goal of the entire vaccine program is not to reduce the infection rate to 0%, but to subdue and weaken the virus so that it can no longer cause severe illness, death, or even going to the hospital.”

Of course, the best case is not to be infected. Still, in fact, the role of the vaccine is to give the people enough protection to fight the virus so that even if the people are infected after the vaccine, they will only have symptoms similar to the general flu, rather than a situation that is so serious that you must be hospitalized.

The Covid-19 epidemic has gradually become severe in Taiwan since May. In less than one month, the cumulative number of local cases has exceeded 6,000 confirmed, and more than 100 people have died. When the epidemic is intensifying, but vaccines are scarce, infectious disease expert Paul Sax suggested that the general public choose any available vaccine.

However, when the number of vaccines in the future is sufficient, it may be the wish of many people to choose the vaccine brand they want to use. The Minister of Health Services Chen Shizhong stated at the press conference for the first time on 6/1 that he is currently planning to let everyone choose the vaccine brand to be administered in the future.

In addition to avoiding the most worrying side effects for the general public, this news is also good news for business people. Because of the current EU regulations, two doses of EU-certified vaccines must be administered within 14 days of entry to obtain a vaccine passport and enter the country without isolation. The currently approved vaccines in Europe include BNT, Modena, AZ, and Johnson & Johnson vaccines.

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