Meanwhile, a case of being confirmed after receiving the Corona 19 vaccine was confirmed in Korea.

You may have been infected before getting the vaccine, or you may have been infected before getting your immunity after vaccination. Let's find out if there are any concerns and how much this can happen.

Dong-chan Cho is a medical reporter.

<Reporter> On the

28th of last month, a nurse at the National Medical Center, who received a Pfizer vaccine, tested for a fever five days later and the next day and was positive for Corona 19.

An additional examination of 40 close contacts confirmed another nurse who received the vaccine on the same day.

The quarantine authorities said there was one more case of infection after vaccination.

[Park Young-joon/Head of Epidemiological Investigation Team, Central Defense Response Headquarters: It is believed that similar cases will be more likely to be reported in the future.] It

is theoretically impossible for the vaccine itself to cause infection, and there are no cases worldwide.

You may have been infected before the vaccine, but you may have been infected without knowing it because it is in an incubation period. Conversely, you may have been infected after the vaccine.

Antibodies are produced one week after vaccination, but it takes about a month for the immunity to be fully activated.

In the United States, there have been two cases of being infected with the Pfizer vaccine.

Two doses of the Pfizer vaccine are 95% effective, so you can get infected even if a month has passed since you received the two vaccines.

That doesn't mean that 5 out of 100 people vaccinated could get coronavirus.

In clinical trials, the number of confirmed cases was compared between those who received the vaccine and those who received the fake drug. In fact, the frequency of infection after vaccination was about 1 in 2,500 people.

[Park Young-jun/Head of Epidemiological Investigation Team, Central Defense Response Headquarters: These people (infected after vaccination) are scheduled to be excluded from the second vaccination.]

Both Pfizer and AstraZeneca vaccines are two doses. The vaccination interval is 3 weeks for Pfizer and Astra The prevention effect is highest at 12 weeks of Zeneca.

The effectiveness of single vaccination of several vaccines that are actually being vaccinated was more than 80%, which was higher than about 60% at the time of clinical trials.

It is said that it is more effective to devise a vaccination strategy so that as many people as possible can get the vaccine at least once.

(Video coverage: Kim Min-cheol, Video editing: Choi Eun-jin)