Let's summarize the contents so far with medical reporter Cho Dong-chan.

Q. What is the reason for the 3rd vaccination interval, '3 months'?

[Cho Dong-chan / Medical reporter (specialist): First, let's look at the recent paper that served as the basis for the third vaccination. A research team from New York University, USA, has seen how the amount of neutralizing antibody changes with time for mutations such as beta and delta after receiving the vaccine. Then, two weeks after the 3rd vaccination, it goes up a lot more than the first time. This is why the 3rd vaccination interval was shortened from 4 months and safely pulled to 3 months, but the problem is that the increase has been confirmed that it only lasted for 2 weeks, and we do not know how long it will be maintained in the future. In the United States, the 3rd dose interval is still 6 months for all ages.]

Q. The interval between doses is 3 months and the validity period is 6 months?

[Cho Dong-chan / Medical reporter (specialist): He must have considered our situation. In Seoul last week, 40% of the COVID-19 deaths were those who had received two doses of the vaccine, and 94% of the deaths were over the age of 60. Also, people in their 50s are still higher than the flu fatality rate. The reason that the 3rd vaccination was extended to three months until the age of 50 is acceptable because it is to minimize the corona death this winter. However, pulling the 3 months from the age of 18 to 40, which has already lowered the fatality rate of the flu with the second vaccination, seems to be for the purpose of reducing the number of confirmed cases. Furthermore, if the purpose of preventing omicron mutation is to secure a variety of vaccines, not the 3rd dose, is more important.]

Q. Will Omicron be blocked by the 3rd inoculation?

[Cho Dong-chan / Medical reporter (specialist): The Pfizer CEO said that the third dose of the vaccine produces 40 times more neutralizing antibodies, so Omicron can be prevented.

Let's look at the Nature Papers.

It is true that neutralizing antibodies are produced 40 times with the third inoculation, but it is mentioned that the preventive effect of Omicron will be lowered.

If there is no neutralizing antibody that blocks Omicron, meeting the other two neutralizing antibodies is of no use.

But let's take a look at the recent Australian research team.

When looking at the amount of Omicron neutralizing antibody for various vaccine combinations, natural infection was the lowest, and the group vaccinated after natural infection had the most.

In terms of vaccines alone, cross-vaccination between AstraZeneca and Pfizer was the most common.

Breakthrough infections, AstraZeneca, and Pfizer also had the lowest number of delta mutations.

The AstraZeneca vaccine will disappear from Korea next year, but we need to reconsider as vaccine diversity is important in preparing for mutations.]