With the prolonged Covid-19 outbreak in Korea, people wonder how many Koreans have developed antibodies against the virus so far.

A recent news report said 0.1 percent of some 1,500 people had antibodies, but the size of the surveyed was too small to be accurate. The government also refuted the report, saying it lacked facts.

The health authorities plan to conduct a poll on 6,000 people whether they have antibodies against the Covid-19 virus until mid-December and disclose partial results on 3,055 this week.

Lee Hyuk-min, director of infection control affairs at the Korean Society for Laboratory Medicine, said the authorities should test at least 10,000 people for antibodies to identify Covid-19 infections more accurately, at a YouTube show Friday by K-Healthlog, a channel operated by The Korea Doctors’ Weekly.

The first results will be from 1,555 leftover serums from a national health and nutrition survey collected from April 21 to June 19, and from 1,500 specimens from patients who visited hospitals in southwestern Seoul from May 25 to May 28.

For the next two months, the government will conduct serum tests as part of the national health and nutrition survey and investigate 1,000 general population as part of the state-supported health checkup in Daegu and North Gyeongsang Province in July and August.

The government should investigate at least 10,000 people to identify Covid-19 infections more accurately, an expert said.

Lee Hyuk-min, director of infection control affairs at the Korean Society for Laboratory Medicine, commented on the need for antibody testing for Covid-19 at a YouTube show Friday by K-Healthlog, a channel operated by The Korea Doctors’ Weekly.

Asked why the nation needs a seroprevalence study to check for antibodies, Lee said it is because Korea needs to complete the overall infection map and epidemiology related to Covid-19.

“About half of Covid-19 patients do not show any symptoms on diagnosis, and 80-90 percent of them show symptoms after testing,” Lee said. “To identify the exact number of infections, we need antibody testing.”

He went on to say that the nation needs large-scale antibody tests with high specificity to detect and respond to Covid-19 infections accurately. The antibody testing result on some 1,500 people showed that only 0.1 percent of them had antibodies, but the outcome is statistically meaningless.

Also, antibody test kits should have high specificity to accurately diagnose those without the disease as negative, rather than high sensitivity, which aims to diagnose those with the disease as positive, Lee explained.

Lee noted that people do not need to be excessively swayed by the result of the antibody retention rate because those who recovered from Covid-19 could contract the virus again.

“The permanent immunity of Covid-19 has little scientific evidence. Some people get infected even after developing a neutralizing antibody to fight the Covid-19 virus,” Lee said.

Waning immunity, referring to a progressive loss of antibodies, is why physicians ask patients to get a booster dose even after they develop immunity through a vaccine injection.

Most of the patients infected with the SARS coronavirus in 2003 also lost their immunity within one year after developing antibodies, and the Covid-19 case is likely to be similar, Lee said.

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