SHARES
Fresh data from China’s COVID-19 epidemic points to the hidden danger of “silent spreaders”, or asymptomatic carriers. In fact, scientists have started saying the COVID-19 virus is a stealth virus.
High Proportion of Silent Spreaders among the infected
In fact the data suggests “silent carriers” were one-third of China’s confirmed cases of >80,000. According to Hong Kong’s South China Morning Post about 43,000 people tested positive for COVID-19 last month had no or very mild symptoms. These 43,000 asymptomatic cases were not part of the national official number.
As a result of continual extensive testing, health authorities found new asymptomatic patients (no symptoms) to those with mild symptoms. Mild symptoms include a slight cough and loss of sense of smell giving rise to concerns that there are people walking around freely but infecting others unknowingly. From the China data, this could be as high as one third of those infected. Data from Korea suggests 20% asymptomatic carriers among those tested.
Transmission and Incubation Periods
Scientists are still gathering data and evidence to understand more the role of asymptomatic transmission and the period of contagion from time of infection to ability to infect others or when symptoms appear.
One measure is 14 days, but the incubation period could be longer from infection to symptoms appearing. From the first start of symptoms to eventual recovery. generally the disease could run for about 2 weeks, except for more serious cases. For severe and critical patients, recovery runs from 3-6 weeks.
Recent data from 3 clusters in Singapore shows incubation period to range from 2-11 days, but the most common or median period is 4 days.
Implications of “Silent Spreaders” danger
As infected people who have no symptoms can spread the virus, it is not enough to avoid those who are unwell. So keep a safe distance of at least one if not two meters. Some experts and health authorities are reconsidering whether people should start wearing masks to help reduce the spread from transmission of droplets, micro-droplets produced when we speak, laugh or sing, even from seemingly healthy people.
Follow these Guidelines to help break transmission:
- Stay home. Avoid going to public places or socialise with anyone outside your home
- Social distancing – Stay 1 to 2 m away from people – whether they are sick or not
- Wash your hands often – for at least 20 seconds with soap
- Do not touch your mouth, nose, and eyes
- Clean and disinfect surfaces in your office, home and car
Remember, the silent spreader may be you. Heed the guidelines and help keep everyone safe.
https://www.npr.org/2020/03/21/819439654/silent-spreaders-speed-coronavirus-transmission
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30528-6/fulltext#fig2
by Wong Mei Chan
View all articles by Wong Mei Chan.
