Infected people carry the same amount of virus with or without symptoms

  Science and Technology Daily, Beijing, August 10 (Reporter Liu Xia) South Korean scientists wrote in the recently published "American Medical Association · Internal Medicine" magazine that their latest research shows that, regardless of whether they have symptoms, the nose, The throat and lungs carry the same amount of viral material, which is an important biological evidence that asymptomatic carriers can transmit the new coronavirus.

  In this study, Li Chengcai's team from Suncheonxiang University School of Medicine (transliteration) analyzed swab samples from 303 quarantined people collected at an isolation point from March 6th to 26th. The ages of this group ranged from 22 to 36 years old, and two thirds were women. Among them, 193 were symptomatic and 110 were asymptomatic, and 89 of them had never had any symptoms.

  After 8 days of isolation, the researchers sampled these people at regular intervals and found that their upper and lower respiratory tract samples contained considerable viral genetic material. Researchers conducted a total of 1,886 tests and found that those who did not have any symptoms at the time of the test, including those who never showed symptoms afterwards, carried as many pathogenic substances in the nose, throat and lungs as those with symptoms.

  Moreover, after conducting regular tests on asymptomatic people, researchers also found that although asymptomatic people clear the virus faster than symptomatic people, the new coronavirus will still persist in their bodies for a period of time. However, the median time for asymptomatic patients to become negative was slightly shorter than that of symptomatic patients, at 17 days and 19.5 days, respectively.

  The researchers said the discovery itself is expected to help people understand which infected people are truly asymptomatic, rather than in a "pre-symptomatic" state.

  The researchers stated that their study cannot "determine how much asymptomatic patients play a role in spreading the new coronavirus."

  Because theoretically speaking, the two noses and throats contain the same amount of virus, which means that the same virus can be transmitted, but asymptomatic people are unlikely to have a severe cough, and this cough will spread virus droplets into the air .

  Dr. Simon Clark, a cell microbiologist at the University of Reading in the United Kingdom, pointed out that although asymptomatic people are at risk of spreading the virus, those with "coughing and spewing the virus" symptoms are at higher risk of spreading the virus. Dr. Andrew Preston, an infection biologist at the University of Bath, said that the risk of contracting the new coronavirus from anyone depends on many factors, including the depth and speed of the infected person’s breathing, the distance from the spreader, Is it in a closed environment?