ER Editor: Dr. Mike Yeadon, former Pfizer CEO, posted a link to this Nature study, published on November 20, 2020, on Twitter within the last few hours. Here is the opening of his thread, which we recommend. Notice his unequivocal remark on how much virus needs to be present in order to transmit an infection. An asymptomatic person, i.e. someone showing no symptoms of sickness, probably has very little if any. Asymptomatic transmission has become one of those covid narrative myths that turns each and every one of us into an bio-enemy of the other.
There is No Asymptomatic Spread
A new paper in Nature has struck a blow against the Covid orthodoxy of asymptomatic spread. Following the lockdown, the city government of Wuhan conducted a city-wide nucleic acid screening for SARS-CoV-2. It was carried out on an impressive scale:
There were 10,652,513 eligible people aged ≥6 years in Wuhan (94.1% of the total population). The nucleic acid screening was completed in 19 days (from May 14th, 2020 to Jun 1st, 2020), and tested a total of 9,899,828 persons from the 10,652,513 eligible people (participation rate, 92.9%). Of the 9899,828 participants, 9,865,404 had no previous diagnosis of COVID-19, and 34,424 were recovered COVID-19 patients.
The results make good reading for lockdown sceptics:
The detection rate of asymptomatic positive cases was very low, and there was no evidence of transmission from asymptomatic positive persons to traced close contacts. There were no asymptomatic positive cases in 96.4% of the residential communities.
Previous studies have shown that asymptomatic individuals infected with SARS-CoV-2 virus were infectious, and might subsequently become symptomatic. Compared with symptomatic patients, asymptomatic infected persons generally have low quantity of viral loads and a short duration of viral shedding, which decrease the transmission risk of SARS-CoV-2. In the present study, virus culture was carried out on samples from asymptomatic positive cases, and found no viable SARS-CoV-2 virus. All close contacts of the asymptomatic positive cases tested negative, indicating that the asymptomatic positive cases detected in this study were unlikely to be infectious.
The report in Nature is a bit technical, but very much worth reading in full.
Lockdown Sceptics readers will recall that Dr Maria van Kerkhove, the technical lead of COVID-19 response and the head of the emerging diseases and zoonosis unit at the World Health Organisation, said the same thing about asymptomatic transmission at a WHO press conference on June 8th:
Question: It’s a question about asymptomatic transmission, if I may. I know the WHO’s previously said there are no documented cases of this. We had a story out of Singapore saying that at least half of the new cases they are seeing have no symptoms and I’m wondering whether its possible this has a bigger role than the WHO initially thought in propagating the pandemic.
Dr Maria Van Kerkhove: We have a number of reports from countries who are doing very detailed contact tracing. They are following asymptomatic cases, they are following contacts and they are not finding secondary transmission onward. It’s very rare and much of that is not published in the literature.
The comment drew sharp criticism at the time, and the WHO swiftly explained that there had been a “misunderstanding”. We will look out for a further update.
Stop Press: The Centre for Disease Control might also want to take a look at these results. They have just released new guidance saying that “Most SARS-CoV-2 infections are spread by people without symptoms“. Not in Wuhan they weren’t.