A woman walks with a mask in her hand on a street in Jung District, Seoul, Friday. The outdoor mask mandate, which went into effect from April 2021, will be fully lifted starting Monday. Yonhap

Waning immunity, emergence of new variants remain concerns

By Lee Hyo-jin

While a recent government study found that almost all Koreans have developed antibodies against the coronavirus either by vaccination or natural infection, this finding does not mean that the population has achieved herd immunity, according to health officials.

The Korea Disease Control and Prevention Agency (KDCA) unveiled on Friday the results of its latest study, which showed that 97.4 percent of those surveyed had antibodies against the spike protein (S) of the coronavirus. The survey, co-organized with the Korea National Institute of Health (NIH), involved some 10,000 people aged five and above living in 17 cities and provinces.

A COVID-19 antibody test checks whether an individual has developed S-antibodies or nucleocapsid protein (N)-antibodies. S-antibodies are produced either through natural infection or vaccination, while the N-antibodies are formed only through natural infection.

Although the vast majority of the population has developed antibodies against the coronavirus, people should still remain vigilant and receive an updated booster shot, health officials warn.

"A positive antibody test result does not necessarily mean that the person has high immunity to the virus. We also do not know the specific antibody levels of the individuals or whether they have neutralizing antibodies," Kwon Joo-wook, director of the NIH said during a briefing. A neutralizing antibody is an antibody that actually defends cells from pathogens and infections.