Only 0.03% test positive for COVID-19 antibodies

The recent research of 3,055 people conducted by the South Korean disease control authorities showed that only one of them had COVID-19 antibodies. Extrapolating it to the country’s 51.78 million populations, it means only 15,500 people have antibodies after a full recovery from COVID-19. The figure is not much different from the total number of confirmed cases as of Thursday – 13,293 cases – which means there weren’t a lot of people who were unaware of their COVID-19 infection with no noticeable symptoms.

The extrapolation of the research should be viewed with caution as its sample size is small and some heavily affected areas, such as Daegu, were left out. However, it is clear that South Korea has a much lower rate of antibodies than other countries. The rates of antibodies in New York, London, Wuhan, which was the origin of the virus, and Tokyo are 21.2 percent, 17 percent, 3.2 percent, and 0.1 percent, respectively while Sweden’s Stockholm, which has chosen the herd immunity route, has 7.3 percent. South Korea’s lower antibody rate reflects the country’s outstanding disease control efforts, which led to a fewer number of patients. However, this means that the country is more vulnerable to the next big wave as fewer people have immunity.

Having a high rate of antibodies is not enough, however. For MERS, the immunity lasts about one year after making a full recovery. According to research conducted by a medical school research team at Chongqing University, 90 percent of those infected with COVID-19 had maintained antibodies for only two to three months. The antibodies of those who did not show any symptoms had a shorter lifespan. The World Health Organization said in April there wasn’t enough evidence that those who have had antibodies after a full recovery from COVID-19 will not get infected again.

In short, herd immunity is unlikely to be the solution. Sweden, for example, has tried to achieve herd immunity with relaxed social distancing rules, but produced 5,485 deaths so far. The country’s number of deaths per one million people is 12 times higher than Norway and 40 percent more than the U.S., which currently has the highest number of COVID-19 deaths. Sweden’s economy hasn’t been doing well either. This year, the economic growth forecast for Sweden is a negative 4.5 percent, which is more depressing than its neighbors that have chosen a rigorous lockdown strategy, namely, Denmark (negative 4.1 percent) and Norway (negative 3.9 percent). As the global supply chain has slowed down, Sweden’s manufacturing sector had no choice other than following the same. While the Danish have reduced consumption by 29 percent, the Swedish also decreased consumption by 25 percent for the fear of infection although their stores have remained open. The Swedish government’s “soft” strategy has only driven up the virus’s fatality rate. In conclusion, wearing a mask and social distancing to prevent infection is the only way before a vaccine is developed – this includes those who got infected and recovered.


Jin-Yeong Lee ecolee@donga.com