Source: OT-Team(AFJ)

As of 12AM on April 1, 55 new asymptomatic COVID-19 infections were reported in mainland China, and totally 1075 cases were still under medical observation. In response, the National Health Commission of the PRC decided to release the daily data of asymptomatic infected cases from April 1st. Additionally, all local governments must make a direct online report within two hours once asymptomatic infected cases are found, and all the close contacts shall be found within 24 hours and put under isolation.

So, what is an asymptomatic infection, exactly? Why is it so important? Here's some professional response to it.

Q&A about Asymptomatic Infection

Q1: What is asymptomatic infection?
A1: The patient should meet two conditions: 1. No clinical symptoms (e. g. fever / cough / sore throat); 2. Positive results were detected for new coronary etiology or serum specific lgM antibody in respiratory tract and other specimens.

Q2: Can asymptomatic infection be a confirmed case?
A2: A suspected or confirmed case requires clinical presentation, which means that the asymptomatic infected people are not diagnosed when they have no symptoms. Besides, only a few of them will develop into confirmed cases, the vast majority will self-healing.

Q3: Is asymptomatic infection contagious? If so, how strong is it?
A3: First, it seems clear that the asymptomatic infected person is an infected person, who carries the novel coronavirus, which may cause transmission. However, infectivity depends on the amount of the virus within the person. The patient without any symptoms must have a low viral load in the body, so the risk of transmission will be small. As per a previous study, the overall contribution of asymptomatic transmission to the epidemic was very small, less than 5%.

Q4: Will the increasing number of asymptomatic cases in mainland China trigger a domestic epidemic backlash?
A4: First, per Zhong Nanshan, head of China's COVID-19 expert team, there are not many asymptomatic infections in China at this stage. Secondly, a complete set of prevention and control measures has been established in China. Even if asymptomatic infections occur, they are under control, and will never cause spread. Also, for individuals, the chance to meet an asymptomatic infected person on the street is virtually nil.

Q5: Since the spread of asymptomatic infection is not high, why should we pay so much attention to it?
A5: Asymptomatic infected people have a strong immune system and wont get sick within 14 days. But the virus still exists in their body, which may last for more than three weeks. Thus, if they are not found and isolated in time, there is a potential risk of community transmission.

Q6Since the symptoms of asymptomatic infection are mild, so how are these cases detected?
A6: The current asymptomatic infections were detected mainly through active screening of close contacts of the confirmed cases, investigation of the source of infection, investigation of the clustering epidemic situation and active detection of persons in high-risk areas, but there are still some asymptomatic infections that are too difficult to be found.

Q7: How shall we prevent and control asymptomatic infection?
A7: First of all, we will do a good job in monitoring asymptomatic infected people, and expand the scope of detection to the close contacts of other asymptomatic infected people, key areas and key populations of the confirmed cases. Once found, the infected person shall be placed under medical observation for 14 days, and the centralized isolation can only be ended after two consecutive negative nucleic acid tests with a 24-hour interval. Moreover, all of their close contacts shall also be quarantined for 14 days too. In addition, once he/she has any symptoms, they must be immediately transferred to the designated hospital for further treatment.

Q8: What shall we do for personal protection?
A8: The public should strengthen the awareness of self-protection. In daily life, they should wash their hands frequently and wear masks, keep a 1 meter distance from others and never go to any gathering places. Once they have a fever, cough or other symptoms, timely accept the standard diagnosis and treatment of medical institutions.

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