Asymptomatic
Transmission
The issue of asymptomatic virus carriers is one of the key assumptions that is used to justify many of the COVID regulations. The idea that anyone, even someone who is not sick, can infect others has led to panic, social distancing, mass testing, etc. After all, if only sick people transmitted the virus, then healthy people would be of no threat or suspicion. As COVID was starting to spread around the world, experts agreed that asymptomatic spread was rare and did not have much of an impact. Anthony Fauci, head of the National Institute of Allergies and Infectious Diseases (NIAID) stated in January 2020, “Even if there is some asymptomatic transmission, in all the history of respiratory-borne viruses of any type, asymptomatic transmission has never been the driver of outbreaks. The driver of outbreaks is always a symptomatic person.”[1]
There are statistical models, based on certain assumptions, that suggest asymptomatic transmission could be a concern.[2] However, several studies were conducted to see if COVID was actually transmitted by asymptomatic carriers. One study from China looked at over 9 million people and found 300 cases of asymptomatic people who tested positive for COVID, and none of the samples had a “viable virus” that would transmit. They followed the close contacts of those asymptomatic cases and found that none of them infected others who were in close contact.[3] Another study published in The Journal of the American Medical Association (JAMA) did a meta-analysis of 54 studies and concluded that asymptomatic transmission even within one household was less than 1%.[4] The WHO also stated that asymptomatic transmissions were very rare. The very next day, after an uproar in the press, the WHO qualified that statement saying not enough is known about asymptomatic spread.[5]
Presymptomatic transmission is when a person is asymptomatic at the time of the test, but then subsequently develops symptoms. Presymptomatic transmission is very difficult to identify since one would need to know the precise moment the transmission took place and if the person was symptomatic or not. Data from a few studies show that transmission maybe 0% - 4% in a household setting, and possibly 16% in a hospital setting.[6]
Infection
In the public discourse about COVID, asymptomatic infection and asymptomatic transmission get confused. Asymptomatic infection means a person has tested positive for the virus but is not showing symptoms. Assuming that the results are not a false positive, this means that the body is successfully fighting off the virus, in other words, a healthy person. Asymptomatic transmission is when the carrier manages to infect someone else while exhibiting no symptoms. This is rare. Asymptomatic infection without transmission is a good thing[7] because it enables the carrier to develop antibodies that protect against future infection[8] and thus future transmission.
The number of asymptomatic people who test positive for COVID (see PCR testing) is significant. One study of a cruise ship with a COVID outbreak showed that 80% of passengers had an asymptomatic infection.[9] Another study in the U.K found that around 86% of the infected people were asymptomatic.[10] As a point of comparison, it is estimated that influenza has a 50% asymptomatic rate, though, unlike COVID, there generally isn’t mass testing for influenza.
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Footnotes:
[1] https://www.youtube.com/watch?v=hHTIrPGjRA4&t=7s&ab_channel=BobEnyart
[2]https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2774707?utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_term=010721
[3] “1,174 close contacts of the asymptomatic cases and found that none of the contacts tested positive”
[4] “Household secondary attack rates... from asymptomatic index cases 0.7%”
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2774102
[5] https://www.cnbc.com/2020/06/08/asymptomatic-coronavirus-patients-arent-spreading-new-infections-who-says.html
[6] https://www.nature.com/articles/s41591-020-1046-6
[7] “[Asymptomatic infection is] a good thing for the individual and a good thing for society.”
https://www.washingtonpost.com/health/2020/08/08/asymptomatic-coronavirus-covid/
[8] “Just 0.02% experienced reinfection”
https://www.israelnationalnews.com/News/News.aspx/295712
[9] “The majority of COVID-19-positive patients were asymptomatic (81%, 104 patients)”
https://thorax.bmj.com/content/75/8/693
[10] “86.1% of those who tested positive for the virus did not report “core” symptoms”