A third of coronavirus cases could be “silent carriers”

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According to the Chinese government, the number of “silent carriers,” that is, those who test positive and show no symptoms or only with a delay, could be around 30 percent, reports the South China Morning Post.

The Chinese figures are also confirmed by a group of Japanese experts led by Hiroshi Nishiura, an epidemiologist at the University of Hokkaido. Among the Japanese patients evacuated from Wuhan, the proportion of infected people without symptoms was 30.8 percent.

There is much evidence to suggest “that a considerable number of cases are underdiagnosed,” the Japanese experts wrote in a letter to the International Journal of Infectious Diseases.

These high numbers contrast with the WHO statements that asymptomatic transmission is “extremely rare.” According to the WHO, asymptomatic infections represent only between one and three percent of cases in the European Union.


In most European countries and the United States, where only people with symptoms are examined, the number of infections continues to rise rapidly. In Germany, for example, according to the Federal Ministry of Health, only those who have flu-like symptoms and have been in a region with coronavirus cases in the past 14 days or have had contact with a confirmed case of coronavirus in the last 14 days.

In Germany, anyone who is symptom-free and has had contact with an infected person is sent without further testing to a 14-day self-quarantine, which is almost never monitored.

In China and South Korea, on the other hand, the number of new infections is decreasing markedly. In both countries, anyone who has had close contact with an infected person is tested, regardless of whether they themselves show symptoms. Anyone who tests positive there is quarantined and monitored by phone, even if they show no signs of being sick.

In South Korea, quarantine violations have so far been punished with a fine of up to 3 million($ 2,500). A new bill provides for a fine of 10 million and up to a year in prison for infractions.


Following the rapid increase in late February, South Korea was able to reduce the number of new infections significantly. Currently, almost 9,000 of the approximately 50 million inhabitants are infected. Fewer than 100 infections are added daily, 111 South Koreans have died of COVID-19 so far.

In many places, there are checkpoints where citizens can be examined quickly, easily, and above all, free of charge. So far, around 300,000 tests have been conducted in South Korea. Around 15,000 residents can be tested per day, thanks in part to more than 40 coronavirus testing facilities.


In total, many more people were screened in South Korea than elsewhere in the world: 5.6 per 1,000 population. In Germany, around 160,000 tests for the coronavirus are carried out every week, which corresponds to 1.9 per 1,000 inhabitants. Only about 30,000 tests have been performed in the United States so far.

South Korea managed to contain the COVID-19 without a curfew and without drastic travel restrictions. Although public life has also been massively reduced and everyone is supposed to keep their distance from each other, the country still rejects total confinement.


In addition to stricter measures, South Korea has considerably more access to its population’s personal information. Local authorities have detailed information on those infected, including age, sex, and movement profile. To minimize the risk of infection, citizens receive personalized information about the risk of contracting the virus in their immediate environment.