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SARS-CoV-2

SARS-CoV-2 is a humanborne coronavirus in the betacoronavirus family. The emergence of SARS-CoV-2 led to the SARS-CoV-2 pandemic to be declared by the World Health Organization.

SARS-CoV-2 stands for Severe Acute Respiratory Syndrome Coronavirus 2. It is named as such due to its relative similarity to the SARS coronavirus that led to a public health emergency in parts of the world in 2003.1) 2)

The SARS-CoV-2 virus is a close genetic relative of two other infamous viruses from recent history: SARS-CoV and MERS-CoV.3)

Related Pages:

SARS-CoV-2 Viral Mechanisms and Characteristics

SARS-CoV-2 is a positively charged, single-stranded RNA virus.

Features

Pathology

  • Dec, 2020 - Liao et al; SARS-CoV-2 in the bile of a patient with COVID-19-associated gallbladder disease.4)

Researchers have found in autopsies that SARS-CoV-2 does get into brain tissue, and can be present for months after infection, though inflammation outside of the lungs was mild.5)

See Spike Protein for a discussion of toxins.

Transmission and Infectivity

Nearly two years into the COVID-19 pandemic, some aspects of transmission is still debated. Contact tracing research out of China showed no asymptomatic viral transmission at all.6) Other research indicates that symptomatic transmission drives the pandemic, but there may be smaller amounts of asymptomatic and presymptomatic spread.7) 8) 9)

Further reading:

  • Jan 7, 2021 - Johansson et al; Asymptomatic and presymptomatic spread 25% less.10)

Aerosolization and Transmissibility

Throughout the pandemic, evidence has piled up suggesting that all or nearly all SARS-CoV-2 tranmission takes place through aerosolized virion particles.11) While Goldberg drum experiments suggested that SARS-CoV-2 could hang in the air for up to three hours,12) more sophisticated experiments showed SARS-CoV-2 aerosols to be viable for only around 20 minutes.13)

Indoor/Outdoor Transmission

SARS-CoV-2 is a highly aerosolized virus, and research shows that nearly all transmission takes place in indoor settings where a poorly ventilated room can fill to a pressurized level with virions. One study (preprint) found that 95% of primary case transmission in Japan took place in closed environments.14)

https://www.irishtimes.com/news/ireland/irish-news/outdoor-transmission-accounts-for-0-1-of-state-s-covid-19-cases-1.4529036

= Transmission among Children and in Schools = Early during the pandemic, there was great debate over whether or not children could transmit SARS-CoV-2 to adults. If they cannot, then they likely cannot generate viral loads enough to get sick. It is likely that they rarely, but sometimes do develop sufficient viral load to get sick and also transmit, but this may happen most off with children who are immunodeficient or immunocompromised.

  • Apr 30, 2020 - Business Insider suggests summary evidence points to some spread by children.15)
  • Mar 19, 2021 Bismarck-Osten et al. The Role of Schools in Transmission of the SARS-CoV-2 Virus: Quasi-Experimental Evidence from Germany.
    • School closures had no significant impact on spread of SARS-CoV-2 either among the children in spill-over effects to older generations. School opening had no impacts, and lower transmission incidence was seen.

Animal Transmission

Early during the COVID-19 pandemic, many laboratories euthanized mice as a preventative measure.16)

Pathways and Cell Entry

At least one research team argues that there is evidence of infection and shed from the human gastrointestinal tract.17)

ACE2 and TMPRSS2 and bears, oh my!

Some research indicates neuroinvasion of SARS-CoV-2: https://www.youtube.com/watch?v=fNFzfwLM72c&t=2s

Fat Cells

Once inside the body, SARS-CoV-2 may infect human adipose tissue, which may be one of the reasons obesity is so highly associated with the COVID-19 disease state and long haul COVID-19 symptoms.18)

Infectivity in Animal Hosts

Numerous animals aside from humans have been noted to be susceptible to SARS-CoV-2 infection. Comparative and structural analysis on 410 vertebrate species predicts a broad host range for infection, specifically among mammals.19) One study still in preprint found SARS-CoV-2 moving rapidly into white-tailed deer populations in North America, with over 80% of the deer testing PCR positive for the virus by early 2021.20)

Immunity

There are competing theories on how people can build immunity to SARS-CoV-2 infection or the resulting COVID-19 disease state.

Herd Immunity

Herd immunity is the condition in which viral outbreaks become rare due to sufficiently low transmission rates of a pathogen. This topic has become controversial during the SARS-CoV-2 pandemic due to a combination of propaganda and changing transmission rates of SARS-CoV-2 variants of interest.

Natural Immunity

Reinfections

During the omicron era, reinfections are rapidly on the rise.21)

Disease

COVID-19

SARS-CoV-2 is a cause of COVID-19, a disease with wide ranging characteristics primarily affecting the respiratory and vascular sysems.

Genetic and Epigenetic Effects of Infection

Chromatin Architecture

  • SARS-CoV-2 Restructures the Host Chromatin Architecture22)

Mutation and Variants

There is debate over the nature of the mutations of SARS-CoV-2, its causes, and the implications. This includes theories that non-sterile COVID-19 vaccines sift virions, generating immunity escape.

See more at SARS-CoV-2 Variants

SARS-CoV-2 Origins Story Controversy

The origins of SARS-CoV-2 are shrowded in mystery, including whether the virus is zoonotic or manmade, or was released accidentially or intentionaly.

1)
Wu, Y., Ho, W., Huang, Y., Jin, D.-Y., Li, S., Liu, S.-L., Liu, X., Qiu, J., Sang, Y., Wang, Q., Yuen, K.-Y., & Zheng, Z.-M. (2020). SARS-CoV-2 is an appropriate name for the new coronavirus. The Lancet, 0(0). https://doi.org/10.1016/S0140-6736(20)30557-2
2)
Feng, D., De Vlas, S. J., Fang, L., Han, X., Zhao, W., Sheng, S., Yang, H., Jia, Z., Richardus, J. H., & Cao, W. (2009). The SARS epidemic in mainland China: bringing together all epidemiological data. Tropical Medicine & International Health, 14(Suppl 1), 4–13. https://doi.org/10.1111/j.1365-3156.2008.02145.x
3)
Rabaan, A. A., Al-Ahmed, S. H., Haque, S., Sah, R., Tiwari, R., Malik, Y. S., Dhama, K., Yatoo, M. I., Bonilla-Aldana, D. K., & Rodriguez-Morales, A. J. (2020). SARS-CoV-2, SARS-CoV, and MERS-COV: A comparative overview. Le infezioni in medicina, 28(2), 174–184.
4)
December, 2020 | Liao et al | Endoscopy (journal) | SARS-CoV-2 in the bile of a patient with COVID-19-associated gallbladder disease | doi: 10.1055/a-1290-7446
5)
December 20, 2021 | Daniel Chertow et al | Nature Portfolio (journal) | SARS-CoV-2 infection and persistence throughout the human body and brain | doi.org/10.21203/rs.3.rs-1139035/v1
8)
https://swprs.org/pre-symptomatic-transmission-is-very-real/| Pre-symptomatic transmission is very real | Swiss Policy Institute | Aug, 2021
10)
January 7, 2021 | Johansson et al | JAMA Network | SARS-CoV-2 Transmission From People Without COVID-19 Symptoms | doi:10.1001/jamanetworkopen.2020.35057
13)
January 10, 2022 | Oswin et al | preprint | doi.org/10.1101/2022.01.08.22268944
14)
Apr 16, 2020 | Nishiura et al | https://doi.org/10.1101/2020.02.28.20029272
18)
Oct 25, 2021 | Martinez-Colon et al | bioRxiv preprint | https://doi.org/10.1101/2021.10.24.465626
19)
September 8, 2020 | Damas et al | PNAS | doi.org/10.1073/pnas.2010146117
20)
November 6, 2021 | Kuchipudi et al | preprint | doi.org/10.1101/2021.10.31.466677
22)
July 21, 2021 | Ruoyu Wang et al | preprint | doi: https://doi.org/10.1101/2021.07.20.453146
sars-cov-2.txt · Last modified: 2022/05/20 08:47 by mathew