Sadly there are those who pretend that Covid19 infected Asymptomatic people are not walking superspreaders. Their motivations are varied. Let us look at actual Science.
Our mouths are home to a richly diverse population of Bacteria, which we propel toward friends and family attached to saliva droplets during normal speech, enhanced by singing. Viruses go along for the ride.1
Of course they live in our noses as well, so a sneeze can be better than a cough in the spread of pathogens.2
How Far will my Cough or Sneeze Travel?
I you have Covid19 feeding and breeding on the ACE2 rich areas of your mouth that the Virus absolutely loves, you will infect many people within a large range as shown in glorious detail. Note the scale is in Metres, or Meters if you prefer.3
How many Covid19 virions can we count?
Our mouths and noses are a fabulous breeding ground for Covid19, much smaller than bacteria, but happily swimming in fluids they call home.
Numerous research groups have used advanced engineering to study the number and size distribution of particles exhaled by humans.45
How many Asymptomatic Carriers are there?
Latest analysis, thanks to one of our illustrious Deep Diving Data crunchers who wishes to remain anonymous, reveals huge numbers of Asymptomatic Covid19 infected people using the US Decoy monitoring system for the Jabbed, known as V-Safe.
It shows a strange spike in numbers immediately after Pfizer changed its formula to include Tromethamine.
Note the huge increase in percentage of registrants who had "breakthrough infections".
This is consistent with a pooled analysis from 95 studies that found 40.5% of cases were Asymptomatic.
26.94% of Close Contacts of Asymptomatic carriers were infected. I would round up following Science of significant digits to 27%. Lovely p values for those who like that sort of thing.6
Different Covid19 Viral Loads with Variants
In the UK, viral load when the Alpha variant hit was significantly greater than found for the Delta wave.7
Viral load shows a wide range for symptomatic carriers
Breakthrough infection in Sweden demonstrated a wide range of viral load for symptomatic and asymptomatic people who suffered breakthrough infections after 3 jabs.8
In Denmark the mean difference of Ct values between symptomatic and asymptomatic participants was not significant.9
A useful review found many Asymptomatic Carriers reported from various countries found that Asymptomatic people account for 40% to 45% of SARS-CoV-2 infections, and they can transmit the virus to others for an extended period, perhaps longer than 14 days. Asymptomatic infection may be associated with subclinical lung abnormalities, as detected by computed tomography.10
Large scale testing in UK showed a difference of no more that 2 PCR cycle times between Symptomatic and Asymptomatic carriers for recent Omicron variants.11
A study in California found no significant difference in cycle threshold values between vaccinated and unvaccinated, asymptomatic and symptomatic groups infected with SARS-CoV-2 Delta.12
Here is their supplementary figure:
A study in Germany by Drosten et al. found similar viral loads in presymptomatic, asymptomatic, and mildly symptomatic cases .13
A large study looked at Delta Variant viral loads of Symptomatic and Asymptomatic infected people detected in Wisconsin on 4 December 2021 and found no significant difference in their viral load.14
I have shortened the caption to their Fig 1. Individuals infected with SARS-CoV-2 despite full vaccination have low Ct values and shed similar amounts of infectious virus as unvaccinated individuals. A. N1 Ct values for SARS-CoV-2-positive specimens were grouped by vaccination status from RT-PCR. N1 Ct values for SARS-CoV-2-positive specimens grouped by vaccination status for individuals who were symptomatic or either asymptomatic or did not have any information, at the time of testing. Light yellow box indicates Ct values <25. C. plaque assays on Vero E6 TMPRSS2 cells. Infectious titers are expressed as plaque-forming units (PFU) per milliliter of specimen.
June 2023 Update - Asymptomatic Superspreader
In early 2021, 36 people volunteers to be deliberately exposed to Covid19 so their infection and exhaled virions could be monitored. They were given tissue culture infectious dose of pre-Alpha wild-type SARS-CoV-2 (Asp614Gly) by Intranasal drops. It was found that Asymptomatic carriers emitted the most deadly virus to infect people around them and their noses were the greatest threat.15
Conclusion
This small sample of the literature is enough to convice me to take special care when meeting others because I could become infected and pass the current variant to others without experiencing symptoms as cases, reinfections and Deaths continue to climb in Australia.16
Austin Willams. June 2020. Doctor demonstrates how face mask blocks respiratory droplets from spreading. https://www.foxla.com/news/doctor-demonstrates-how-face-mask-blocks-respiratory-droplets-from-spreading
Mahesh Jayaweera, Hasini Perera, Buddhika Gunawardana, Jagath Manatunge. 2020. Transmission of COVID-19 virus by droplets and aerosols: A critical review on the unresolved dichotomy. https://www.researchgate.net/publication/342157309_Transmission_of_COVID-19_virus_by_droplets_and_aerosols_A_critical_review_on_the_unresolved_dichotomy
Kristen K. Coleman, Douglas Jie Wen Tay, Kai Sen Tan, Sean Wei Xiang Ong, The Son Than, Ming Hui Koh, Yi Qing Chin, Haziq Nasir, Tze Minn Mak Justin Jang Hann Chu,Donald K. Milton, Vincent T. K. Chow, Paul Anantharajah Tambyah, Mark Chen, and Kwok Wai Tham. August 2021. Clinical Infectious Diseases. 74(10):1722-8. https://academic.oup.com/cid/article/74/10/1722/6343417
Jinho Lee, Danbi Yoo, Seunghun Ryu, Seunghon Ham, Kiyoung Lee, Myoungsouk Yeo, Kyoungbok Min, Chungsik Yoon. 2019. Quantity, Size Distribution, and Characteristics of Cough-generated Aerosol Produced by Patients with an Upper Respiratory Tract Infection. Aerosol and Air Quality Research. 19:840-853. https://aaqr.org/articles/aaqr-18-01-oa-0031
Qiuyue Ma, Jue Liu, Qiao Liu, Liangyu Kang, Runqing Liu, Wenzhan Jing, YuWu, Min Liu. December 2021. Global Percentage of Asymptomatic SARS-CoV-2 Infections Among the Tested Population and Individuals With Confirmed COVID-19 Diagnosis. A Systematic Review and Meta-analysis. JAMA Network Open. 4(12):e2137257. doi:10.1001/jamanetworkopen.2021.37257 https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2787098
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1009243/Technical_Briefing_20.pdf
Ulrika Marking, Sebastian Havervall, Nina Greilert Norin, Oscar Bladh, Wanda Christ, Max Gordon, Henry Ng, Kim Blom, Mia Phillipson, Sara Mangsbo, Anna Smed Sörensen, Peter Nilsson, Sophia Hober, Mikael Åberg, Jonas Klingström, Charlotte Thålin. Septembr 2022. Correlates of protection, viral load trajectories and symptoms in BA.1, BA.1.1 and BA.2 breakthrough infections in triple vaccinated healthcare workers. https://www.medrxiv.org/content/10.1101/2022.04.02.22273333v2
Cæcilie Leding, Julia Skov, Katrine Uhrbrand, Jan Gorm Lisby, Katrine Pedersbæk Hansen, Thomas Benfield and Louise Katrine Duncan. 2022. Detection of SARS‑CoV‑2 in exhaled breath from non‑hospitalized COVID‑19‑infected individuals. Nature Scientific Reports. 12:11151. https://www.nature.com/articles/s41598-022-15243-1
Daniel P. Oran and Eric J. Topol. Prevalence of Asymptomatic SARS-CoV-2 Infection: A Narrative Review. June 2020. Annals of Internal Medicine. 173(5) https://www.acpjournals.org/doi/10.7326/M20-3012
Matthew Whitaker, Joshua Elliott, Barbara Bodinier, Wendy Barclay, Helen Ward, Graham Cookec, Christl A. Donnellya, Marc Chadeau-Hyama, Paul Elliott. May 2022. Variant-specific symptoms of COVID-19 among 1,542,510 people in England. https://www.medrxiv.org/content/10.1101/2022.05.21.22275368v1
Preprint. Charlotte B. Acharya, John Schrom, Anthea M. Mitchell, David A. Coil, Carina Marquez, Susana Rojas, Chung Yu Wang, Jamin Liu, Genay Pilarowski, Leslie Solis, Elizabeth Georgian, Maya Petersen, Joseph DeRisi, Richard Michelmore, Diane Havlir. October 2021. No Significant Difference in Viral Load Between Vaccinated and Unvaccinated, Asymptomatic and Symptomatic Groups When Infected with SARS-CoV-2 Delta Variant. https://www.medrxiv.org/content/10.1101/2021.09.28.21264262v2
Now published with more authors. Charlotte B Acharya, John Schrom, Anthea M Mitchell, David A Coil, Carina Marquez, Susana Rojas, Chung Yu Wang, Jamin Liu, Genay Pilarowski, Leslie Solis, Elizabeth Georgian, Sheri Belafsky, Maya Petersen, Joseph DeRisi, Richard Michelmore , Diane Havlir. Viral Load Among Vaccinated and Unvaccinated, Asymptomatic and Symptomatic Persons Infected With the SARS-CoV-2 Delta Variant. May 2022. Open Forum Infectious Diseases. Volume 9(5) ofac135, https://doi.org/10.1093/ofid/ofac135
Terry C. Jones, Guido Biele, Barbara Mühlemann, Talitha Veith, Julia Schneider, Jörn Beheim-Schwarzbach, Tobias Bleicker, Julia Tesch, Marie Luisa Schmidt, Leif Erik Sander, Florian Kurth, Peter Menzel, Rolf Schwarzer, Marta Zuchowski, Jörg Hofmann, Andi Krumbholz, Angela Stein, Anke Edelmann, Victor Max Corman, Christian Drosten. July 2021. Estimating infectiousness throughout SARS-CoV-2 infection course. Science 373:180. https://www.science.org/doi/10.1126/science.abi5273
Kasen K. Riemersma, Luis A. Haddock III, Nancy A. Wilson, Nicholas Minor, Jens Eickhoff, Brittany E. Grogan, Amanda Kita-Yarbro, Peter J. Halfmann, Hannah E. Segaloff, Anna Kocharian, Kelsey R. Florek, Ryan Westergaard, Allen Bateman, Gunnar E. Jeppson, Yoshihiro Kawaoka, David H. O’Connor, Thomas C. Friedrich, Katarina M. Grande. 2022. Shedding of infectious SARS-CoV-2 despite vaccination. PLoS Pathog 18(9): e1010876. https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1010876
Jie Zhou, Anika Singanayagam*, Niluka Goonawardane, Maya Moshe, Fiachra P Sweeney, Ksenia Sukhova, Ben Killingley, Mariya Kalinova, Alex J Mann, Andrew P Catchpole, Michael R Barer, Neil M Ferguson, Christopher Chiu, Wendy S Barclay. August 2023. Viral emissions into the air and environment after SARS-CoV-2 human challenge: a phase 1, open label, first-in-human study. The Lancet Microbe. 4:e579-90. https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(23)00101-5/fulltext
https://www.worldometers.info/coronavirus/country/australia/