Transmission of 2019-nCoV Infection From an Asymptomatic Contact
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Can the novel coronavirus (2019-nCoV) be transmitted by asymptomatic people?
All the news agencies around the world have been focused on this new coronavirus (2019-nCoV). The number of people infected is growing exponentially and eclipsing the numbers seen with the SARS virus. The question is why is the spread so rapid?
Traditionally, we believe that only symptomatic patients are able to transmit the virus. So active sneezing and coughing would send the viral particles in water droplets into the air and then another host can breathe them in, and the whole cycle of infection begins in the new host.
However, there were reports that the Chinese health minister had hinted that this virus could be transmitted by an asymptomatic person. This means that, even during the incubation period, the virus can be transmitted. If this is true, then stopping the spread of the virus would be much more difficult because people that look well could still spread the virus. The health minister did not provide any scientific data to support this concept.
Then, on January 30, 2020, this letter to the editor detailed a case in Germany wherein a Shanghai resident came to Germany on a business trip and interacted with several of her colleagues. On her return flight to China, she became ill and later tested positive for the novel coronavirus. Of the colleagues, 1 person was infected and then subsequently another 3 tested positive for the novel virus. During her stay, the Shanghai resident had been well, with no signs or symptoms of infection. This case seemed to support the concept of transmission during the incubation period.
However, according to a report on CNN, the “Bavarian health authorities and the Robert Koch Institute in Chinese language revealed that she might have had mild unspecific symptoms including back pain and also took antipyretic medication." This means that she was symptomatic, making viral copies, and, hence, able to transmit the disease. So, this is not a case of transmission during the incubation period in the strict sense.
According to the same CNN report, the WHO had stated that "the main driver of transmission...is symptomatic cases." It goes on to say that WHO is "aware of possible transmission from asymptomatic individuals in a few instances but said that this may be rare and not a major player in the spread of the virus.”
The takeaway from this is that the bulk of the transmissions are made in the traditional ways, with symptomatic patients sneezing and coughing out the viruses. We also have to acknowledge that people during the incubation period do have the virus on board, so there is a potential risk that they may pass it on. However, due to the lower viral load, the contact might need to be in much closer proximity in order to transmit the virus.
Just as a reminder to all of us, the virus has no way to move on its own and it needs us to get into the lung tissue. Stay away from sneezing people because the virus particles can be inhaled. Virus particles can settle on tables, floors, and backpacks, and our hands pick up the virus and bring it up to the face, where again the virus can be inhaled. The simple rules are to avoid sneezy people and don’t touch your hands to your face. If you are going to touch your face then you must wash your hands. If you are coughing, then cough into a tissue and throw it away. These simple things will stop the virus from finding a new host. No host, no equipment to make the virus, so no more virus, and then this nightmare will stop. That is what basically brought SARS to a close. The virus could not find another host. So, we need to tell our patients not to panic because the virus is very weak. It needs us to move it to target. So, let’s stop helping the virus.
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