September Antibody Positivity Rate Survey Results Announced... "Speed and Sample Size Disappointing"

Sample collection begins first week of August... 10,000 samples
"Should have started immediately after announcing testing plan"

[Image source=Yonhap News]

[Asia Economy Reporter Kim Young-won] The quarantine authorities have announced the status of a large-scale COVID-19 antibody positivity rate survey. While the intention of this survey to confirm the scale of 'undiagnosed infections' and reflect it in future quarantine policies is good, there are also opinions that the sample size and testing speed are disappointing.

The Central Disease Control Headquarters stated that specimen collection for the antibody positivity rate survey will begin in the first week of next month, and the test results will be announced in early September. Previously, the government had started the survey in mid-May and planned to produce test results this month, but it was delayed by about two months due to administrative procedures. The survey is being conducted in cooperation with 258 public health centers in 17 metropolitan cities and provinces nationwide, 34 participating local universities, and city, county, and district offices. The government plans to identify the exact scale of natural infections and undiagnosed infections in local communities by conducting blood tests as well as surveys to understand previous diagnosis history, vaccination history, and underlying diseases.

This survey investigates the positivity rates of N antibodies, which are formed through natural infection, and S antibodies, which can be produced through both natural infection and vaccination. If N antibodies are present, it can be considered that there is a history of infection. However, the 'antibody titer survey,' which indicates the level of antibody presence, will be conducted only on a portion of the total samples. Kim Dong-hyun, professor of preventive medicine at Hallym University College of Medicine and the person responsible for this antibody positivity rate survey and research, said, "Antibody titer, or immunity surveys, require neutralizing antibody tests, which are very expensive and time-consuming," adding, "It is expected to be conducted only on a portion of the 10,000 samples."

The samples will be divided regionally considering population distribution and characteristics. For example, more samples will be allocated to the densely populated metropolitan area. Professor Kim explained, "Samples are allocated proportionally to the population," and "households of subjects are selected by city, county, and district units."

Some have expressed disappointment regarding the sample size and the speed of the survey. Baek Soon-young, emeritus professor at Catholic University College of Medicine, said, "This should have been done quickly at the announced time of testing commencement, but the process was delayed, and the sample size of 10,000 is also small," adding, "It is not necessary to conduct a new blood collection survey; using residual serum from health checkups could allow testing of about 100,000 people without difficulty."

Professor Chun Eun-mi of the Department of Respiratory Medicine at Ewha Womans University Mokdong Hospital said, "Since there are research results showing that natural immunity is better in the long term than immunity from the third vaccine dose, it is good to establish second-half year measures based on the September survey results," but also pointed out, "However, if that is the case, it raises the question of why the target for the fourth vaccination is being expanded and recommended now."

Meanwhile, countries such as Canada, the United Kingdom, and the United States have been conducting antibody positivity rate surveys through blood tests for some time. According to blood test results conducted by the U.S. Centers for Disease Control and Prevention (CDC) from January 27 to February 26, the antibody positivity rate through infection was 57.7%. The UK Health Security Agency (UKHSA) conducted a survey targeting citizens aged 17 and older from January 31 to March 27, and the antibody positivity rate through infection was 45.0%, about 14.6 percentage points higher than the confirmed case rate of 30.4% relative to the UK population during the same period.

In Canada, the antibody positivity rate survey was conducted by classifying socioeconomic levels. Among five groups, the group with the lowest socioeconomic level showed a higher antibody positivity rate through infection than the group with the highest socioeconomic level.

This content was produced with the assistance of AI translation services.