COVID-19 (SARS-CoV-2) Research

	Mark C. Griffin Associate Professor, Department of Anthropology San Francisco State University
Mortui vivos docent

COVID-19 Research

Accurate, up-to-date information is vital in a pandemic.

Below is some of the important research to help understand the pandemic.

The WHO maintains a comprehensive database of the current research.

Current COVID-19 numbers.

COVID-19 statistics.

COVID-19 Myths

The science is divided on the effectiveness of mask wearing
The scientific evidence regarding the effectiveness of masks to limit the spread of viruses is unequivocal. There is no debate. Masks are the single most effective way to limit the giving and getting the virus (see The Efficacy of Mask Wearing).
The evidence for airborne transmission of SARS-CoV-2 is overwhelming (see How SARS-CoV-2 is Spread). The vast majority of infections are transmitted by asymptomatic hosts (Li et al., 2020; Ma et al., 2020). Each infected person, symptomatic or not, can potentially transmit the virus to more than six other people (Tang et al., 2020). The densest concentrations of the cells that become infected with SARS-CoV-2 are found in the nose, eyes, and gut (Lukassen et al., 2020). If you are not covering your nose and eyes, you're exposed. As researchers point out, if you can smell someone's breath, you're inhaling their microbes.

The vast majority of COVID-19 patients recover
As journalists frequently caution, this statement needs context (see Disease Progression). While it is true that the majority of COVID-19 patients do recover, it is important to take note of the fact that they do so with long-term and possibly permanent organ damage (Akhmerov & Marban, 2020; Meng et al., 2020); Wang et al., 2020). The long-term damage in recovered patients includes acute respiratory distress syndrome, heart arrhythmia, myocarditis, kidney abnormalities, and neurological abnormalities like strokes and shifts in consciousness. This long-term damage manifests in patients that were otherwise healthy before COVID-19. Even asymptomatic infected individuals show significant organ damage (Long et al., 2020; Oran & Topol, 2020; Puntmann et al., 2020).

My region is safe because we don't have that many cases
As academics like to say, there's a lot to unpack here (see How SARS-CoV-2 is Spread). A recent study points out that this type of statement reflects a fundamental misunderstanding of how exponential growth works (Lammers et al., 2020). Each infected person, symptomatic or not, can potentially transmit the virus to more than six other people (Tang et al., 2020). At the lowest transmission estimates for COVID-19 (cases double every three days), one initial case in your region turns into 1,024 in thirty days. If your region has one active case, you're potentially in trouble. Infected individuals are infectious for up to five days before they show symptoms (Cheng et al., 2020). Because as many as 86% of infected persons do not exhibit symptoms, the virus can be spreading quietly in a community for days or weeks before it seems to explode into out of control outbreaks (Li et al., 2020; Ma et al., 2020). By the time a community realizes that the infection has spread, it's too late. Winter is coming.

I'm safe because I'm not in a vulnerable group
It's referred to as a novel virus because the human immune system has never experienced it. If you're human, you're vulnerable (see Disease Progression). A serious mistake that is frequently made is using the terminology commonly applied to influenza to COVID-19 (i.e., vulnerable groups). Half of the ICU admitted COVID-19 patients in New York were under the age of 63 (Richardson et al., 2020) and 32% of ICU admitted COVID-19 patients in Italy had no "underlying conditions" (Grasselli et al., 2020). There is also emerging evidence that COVID-19 can manifest in children as an aggressive inflammatory syndrome (Riphagen et al., 2020; Verdoni et al., 2020).

The Origin and Evolution of SARS-CoV-2

The DNA "fingerprint" almost certainly indicates an origin of SARS-CoV-2 in bats (Andersen et al., 2020; Forster et al., 2020; Li et al., 2020). This is not surprising because of the plethora of coronaviruses harbored by bats (Banerjee et al., 2020). The intermediate host from bats to humans remains somewhat more elusive. Pangolins are frequently cited as the most likely candidate (Zhang et al., 2020). Research indicates that SARS-CoV-2 was in wide circulation well before the first described cluster of cases in Wuhan from late-December 2019 (Pekar et al., 2021).

The uncontrolled spread of the virus, especially in the United States, has allowed SARS-CoV-2 to rapidly accumulate mutations (Lauring and Hodcroft, 2021; Moore & Offit, 2021). Some of these mutations show ability to evade antibodies acquired in response to previous infection and vaccination (Clark et al., 2021; Garcia-Beltran et al., 2021; Kemp et al., 2021; Liu et al., 2021; Wang et al., 2021).

Andersen, K. G., Rambaut, A., Lipkin, W. I., Holmes, E. C., & Garry, R. F. (2020). The proximal origin of SARS-CoV-2. Nature Medicine https://doi.org/10.1038/s41591-020-0820-9

Banerjee, A., Subudhi, S., Rapin, N., Lew, J., Jain, R., Falzarano, D., & Misra, V. (2020). Selection of viral variants during persistent infection of insectivorous bat cells with Middle East respiratory syndrome coronavirus. Scientific Reports, 10, 7257. http://dx.doi.org/10.1038/s41598-020-64264-1

Clark, S. A., Clark, L. E., Pan, J., Coscia, A., McKay, L. G. A., Shankar, S., Johnson, R. I., Brusic, V., Choudhary, M. C., Regan, J., Li, J. Z., Griffiths, A., & Abraham, J. (2021). SARS-CoV-2 evolution in an immunocompromised host reveals shared neutralization escape mechanisms. Cell, March 16. doi: 10.1016/j.cell.2021.03.027

Cyranoski, D. (2020). Mystery deepens over animal source of coronavirus. Nature, 579, 18-19. https://doi.org/10.1038/d41586-020-00548-w

Forni, D., Cagliani, R., Clerici, M., & Sironi, M. (2020). Molecular evolution of human coronavirus genomes. Trends in Microbiology, 25(1), 35-48. https://doi.org/10.1016/j.tim.2016.09.001

Forster, P., Forster, L., Renfrew, C., & Forster, M. (2020). Phylogenetic network analysis of SARS-CoV-2 genomes. Proceedings of the National Academy of Sciences, http://dx.doi.org/10.1073/pnas.2004999117

Garcia-Beltran, W. F., Lam, E. C., St. Denis, Nitido, K. A. D., Garcia, Z. H., Hauser, B. M., Feldman, J., Pavlovic, M. N., Gregory, D. J., Poznansky, M. C., Sigal, A., Schmidt, A. G., Iafrate, A. J., Naranbhai, V., & Balazs, A. B. (2021). Multiple SARS-CoV-2 variants escape neutralization by vaccine-induced humoral immunity. Cell, March 12. doi: 10.1016/j.cell.2021.03.01

Kemp, S. A., Collier, D. A., Datir, R. P., Ferreira I. A. T. M., Gayed, S., Jahun, A., Hosmillo, M., Rees-Spear, C., Mlcochova, P., Lumb, I. U., Roberts, D. J., Chandra A., Temperton, N., The CITIID-NIHR BioResource COVID-19 Collaboration, The COVID-19 Genomics UK (COG-UK) Consortium, Sharrocks, K., Blane, E., Modis, Y., Leigh, ... & Gupta, R. K. (2021). SARS-CoV-2 evolution during treatment of chronic infection. Nature, February 5. doi: 10.1038/s41586-021-03291-y

Li, X., Song, Y., Wong, G., & Cui, J. (2020). Bat origin of a new human coronavirus: there and back again. Science China Life Sciences, 63, 461-462. https://doi.org/10.1007/s11427-020-1645-7

Liu, Z., Van Blargan, L. A., Bloyet, L., Rothlauf, P. W., Chen, R. E., Stumpf, S., Zhao, H., Errico, J. M., Theel, E. S., Liefeskind, M. J., Alford, B., Buchser, W. J., Ellebedy, A. H., Fremont, D. H., Diamond, M. S., & Whelan, S. P. J. (2021). Identification of SARS-CoV-2 spike mutations that attenuate monoclonal and serum antibody neutralization. Cell Host and Microbe, 29(3), 477-488. doi: 10.1016/j.chom.2021.01.014

Moore, J. P. & Offit, P. A. (2021). SARS-CoV-2 vaccines and the growing threat of viral variants. JAMA, 325(9), 821-822. doi: 10.1001/jama.2021.1114

Pekar, J., Worobey, M., Moshiri, N., Scheffler, K., & Wertheim, J. O. (2021). Timing the SARS-CoV-2 index case in Hubei province. Science, March 18. doi: 10.1126/science.abf8003

Thompson, E. C., Rosen, L. E., Sheperd, J. G., Spreafico, R., da Silva Filipe, A., Wojcechowskyj, J. A., Davis, C., Piccoli, L., Pascall, D. J., Dillen, J., Lytras, S., Czudnochowski, N., Shah, R., Meury, M., Jesudason, N., De Marco, A., Li, K., Bassi, J., O'Toole, A., ... & Hughes, J. (2021). Circulating SARS-CoV-2 spike N439K variants maintain fitness while evading antibody-mediated immunity. Cell, 184, 1171-1187. doi: 10.1016/j.cell.2021.01.037

van Dorp, L., Acman, M., Richard, D., Shaw, L. P., Ford, C. E., Ormond, L., Owen, C. J., Pang, J., Tan, C. C. S., Boshier, F. A. T., Ortiz, A. T., & Balloux, F. (2020). Emergence of genomic diversity and recurrent mutations in SARS-CoV-2. Infection, Genetics and Evolution, In Press. https://doi.org/10.1016/j.meegid.2020.104351

Wang, P., Nair, M. S., Liu, L., Iketani, S., Luo, Y., Guo, Y., Wang, M., Yu, J., Zhang, B., Kwong, P. D., Graham, B. S., Mascola, J. R., Chang, J. Y., Yin, M. T., Sobieszczyk, M., Kyratsous, C. A., Shapiro, L., Sheng, Z., Huang, Y., & Ho, D. D. (2021). Antibody resistance of SARS-CoV-2 variants B.1.351 and B.1.1.7. Nature, March 8. doi: 10.1038/s41586-021-03398-2

Zhang, T., Wu, Q., & Zhang, Z. (2020). Probable pangolin origin of SARS-CoV-2 associated with the COVID-19 outbreak. Current Biology, 30(7), 1346-1351. https://doi.org/10.1016/j.cub.2020.03.022

Zhang, C., Zheng, W., Huang, X., Bell, E. W., Zhou, X., & Zhang, Y. (2020). Protein structure and sequence reanalysis of 2019-nCoV genome refutes snakes as its intermediate host and the unique similarity between its spike protein insertions and HIV 1. Journal of Proteome Research 10.1021/acs.jproteome.0c00129

How SARS-CoV-2 is Spread

SARS-CoV-2 is highly transmissible. The level of contagiousness of a pathogen is generally expressed as R₀ (basic reproduction number). The R₀ of a pathogen specifically refers to the average number of secondary infections caused by a single infectious individual. The R₀ for SARS-CoV-2 is estimated to be as high as 6.47 compared with 4.91 for SARS, 3.5-6.7 for MERS (Tang et al., 2020; Distante et al., 2020), and 1.4-2.8 for the H1N1 outbreak of 1918 (Coburn et al., 2009).

The likelihood of infection also seems to be directly related to viral load (Shia et al., 2020). That is, being exposed to one person that is shedding intact viral particles at a high load is just as effective for transmission as being exposed to multiple individuals shedding at much lower levels (He et al., 2020). Viral loads vary from individual to individual, at different stages of infection, and by age group. Research has shown that children younger than five years carry viral loads that are 100 times higher than older age groups (Sargent et al., 2020).

An important caveat for COVID-19 is the emerging evidence of "superspreading" events, that lead to large clusters of cases (Beldomenico, 2020; Kupferschmidt, 2020). That is, the large variation from region to region in infection rates and mortality are likely the result of "superspreaders" that are transmitting the virus to large numbers of people. "Superspreaders" are individuals that for some reason manifest higher than average viral loads. These individuals are capable of infecting huge numbers of others (nearly 200 in at least one case) and those subsequently infected individuals also have high viral loads (Beldomenico, 2020; Kupferschmidt, 2020).

Research indicates that a large proportion of infections from SARS-CoV-2 (as much as 86%) originate from mildly symptomatic or asymptomatic people (Cheng et al., 2020; Li et al., 2020; Ma et al., 2020). Asymptomatic patients shed the virus at rates similar to symptomatic patients and shed the virus for a longer period of time (Lee et al., 2020). Even patients who eventually become symptomatic have been shown to shed high viral loads more than five days prior to exhibiting symptoms (Jiang et al., 2020)

The evidence for airborne aerosol transmission is overwhelming (Azimi et al., 2020; Lednicky et al., 2020; Ong et al., 2020; Santarpia et al., 2020; Setti et al., 2020; Somsen et al., 2020; Yan & Lan, 2020; Zhang et al., 2020). That is, viral particles expelled in normal breath or speech can remain suspended in aerosol clouds in indoor air for at least thirty minutes. Droplets expelled from normal speech are also a likely mode of viral transmission (Stadnytskyi et al., 2020). Another alarming finding is that viral RNA is frequently found in fecal material.

Amirian, E. S. (2020). Potential fecal transmission of SARS-CoV-2: Current evidence and implications for public health. International Journal of Infectious Diseases, In Press. https://doi.org/10.1016/j.ijid.2020.04.057

Azimi, P., Keshavarz, Z., Laurent, J. G. C., Stephens, B. R., & Allen, J. G. (2020). Mechanistic transmission modeling of COVID-19 on the Diamond Princess Cruise Ship demonstrates the importance of aerosol transmission. medRxiv https://doi.org/10.1101/2020.07.13.20153049

Beldomenico, P. M. (2020). Do superspreaders generate new superspreaders? A hypothesis to explain the propagation pattern of COVID-19. International Journal of Infectious Diseases, In Press. https://doi.org/doi:10.1016/j.ijid.2020.05.025

Bourouiba, L. (2020). Turbulent gas clouds and respiratory pathogen emissions potential implications for reducing transmission of COVID-19. JAMA, March 26, 2020. https://doi.org/10.1001/jama.2020.4756

Caputo, A., Aslanian, S., & Craft, W. (2020, April 23). A Covid-infected attendee emerges from CES, a massive tech conference in January. Retrieved from https://www.apmreports.org/story/2020/04/23/covid-infected-attendee-ces-tech-conference

Cheng, H., Jian, S., Liu, D., Ng, T., Huang, W., & Lin, H. (2020). Contact tracing assessment of COVID-19 transmission dynamics in Taiwan and risk at different exposure periods before and after symptom onset. JAMA Internal Medicine, May 1, 2020. doi:10.1001/jamainternmed.2020.2020

Coburn, B. J., Wagner, B. G. & Blower, S. (2020). Modeling influenza epidemics and pandemics: insights into the future of swine flu (H1N1). BMC Medicine, 7, 30. https://doi.org/10.1186/1741-7015-7-30

Distante, C., Piscitelli, P., & Miani, A. (2020). Covid-19 outbreak progression in Italian regions: Approaching the peak by the end of March in northern Italy and first week of April in southern Italy. International Journal of Environmental Research and Public Health, 17(9), 3025. https://doi.org/10.3390/ijerph17093025

Ghinai, I., Woods, S., Ritger, K. A., D. McPherson, T. D., Black, S. R., Sparrow, L., Fricchione, M. J., Kerins, J. L., Pacilli, M., Ruestow, P. S., Arwady, M. A., Beavers, S. F., Payne, D. C., Kirking, H. L., & Layden, J. E. (2020). Community transmission of SARS-CoV-2 at two family gatherings - Chicago, Illinois, February - March 2020. Morbidity and Mortality Weekly Report ePub, 69, early release 8 April 2020. http://dx.doi.org/10.15585/mmwr.mm6915e1

He, X., Lau, E. H. Y., Wu, P., Deng, X., Wang, J., Hao, X., Lau, Y. C., Wong, J. Y., Guan, Y., Tan, X., Mo, X., Chen, Y., Liao, B., Chen, W., Hu, F., Zhang, Q., Zhong, M., Wu, Y., Zhao, L., ... & Leung, G. M. (2020). Temporal dynamics in viral shedding and transmissibility of COVID-19. Nature Medicine, https://doi.org/10.1038/s41591-020-0869-5

Jiang, F., Jiang, X., Wang, Z., Meng, Z., Shao, S., Anderson, B. D., & Ma, M. (2020). Detection of severe acute respiratory syndrome coronavirus 2 RNA on surfaces in quarantine rooms. Emerging Infectious Diseases, 26(9). https://doi.org/10.3201/eid2609.201435

Kampf, G. (2020). Potential role of inanimate surfaces for the spread of coronaviruses and their inactivation with disinfectant agents. Infection Prevention in Practice, 2(2), 100044. https://doi.org/10.1016/j.infpip.2020.100044

Kupferschmidt, K. (2020). Case clustering emerges as key pandemic puzzle. Science, 368(6493), 808-809. https://doi.org/10.1126/science.368.6493.808

Lauer, S. A., Grantz, K. H., Bi, Q., Jones, F. K., Zheng, Q., Meredith, H. R., Azman, A. S., Reich, N. G., & Lessler, J. (2020). The incubation period of coronavirus disease 2019 (COVID-19) from publicly reported confirmed cases: Estimation and application. Annals of Internal Medicine, https://doi.org/10.7326

Lednicky, J. A., Lauzardo, M., Fan, Z. H., Jutla, A., Tilly, T. B., Gangwar, M., Usmani, M., Shankar, S. N., Mohamed, K., Eiguren-Fernandez, A., Stephenson, C. J., Alam, M., Elbadry, M. A., Loeb, J. C., Subramaniam, K., Waltzek, T. B., Cherabuddi, K., Morris, J. G. Jr., & Wu, C. (2020). Viable SARS-CoV-2 in the air of a hospital room with COVID-19 patients. medRxiv, August 4. https://doi.org/10.1101/2020.08.03.20167395

Lee, S., Kim, T., Lee, E., Lee, C., Kim, H., Rhee, H., Park, S. Y., Son, H., Yu, S., Park, J. W., Choo, E. J., Park, S., Loeb, M., & Kim, T. H. (2020). Clinical course and molecular viral shedding among asymptomatic and symptomatic patients with SARS-CoV-2 infection in a community treatment center in the Republic of Korea. JAMA Internal Medicine, August 6. doi:10.1001/jamainternmed.2020.3862

Li, J., Zhang, L., Liu, B., & Song, D. (2020). Case report: Viral shedding for 60 days in a woman with novel coronavirus disease (COVID-19). The American Journal of Tropical Medicine and Hygiene, In Press. https://doi.org/10.4269/ajtmh.20-0275

Li, R., Pei, S., Chen, B., Song, Y., Zhang, T., Yang, W., & Shaman, J. (2020). Substantial undocumented infection facilitates the rapid dissemination of novel coronavirus (SARS-CoV-2). Science, 368(6490), 489-493. DOI: 10.1126/science.abb3221

Li, W., Su, Y., Zhi, S., Huang, J., Zhuang, C., Bai, W., Wan, Y., Meng, X., Zhang, L., Zhou, Y., Luo, Y., Ge, S., Chen, Y., & Ma, Y. (2020). Viral shedding dynamics in asymptomatic and mildly symptomatic patients infected with SARS-CoV-2. Clinical Microbiology and Infection, July 8. https://doi.org/10.1016/j.cmi.2020.07.008

Liu, Y., Ning, Z., Chen, Y., Guo, M., Liu, Y., Gali, N. K., Sun, L., Duan, Y., Cai, J., Westerdahl, D., Liu, X., Ho, K., Kan, H., Fu, Q., & Lan, K. (2020). Aerodynamic analysis of SARS-CoV-2 in two Wuhan Hospitals. Nature, Ahead of print https://doi.org/10.1038/s41586-020-2271-3

Lukassen, S., Chua, R. L., Trefzer, T., Kahn, N. C., Schneider, M. A., Muley, T., Winter, H., Meister, M., Veith, C., Boots, A. W., Hennig, B. P., Kreuter, M., Conrad, C., & Eils, R. (2020). SARS-CoV-2 receptor ACE2 and TMPRSS2 are primarily expressed in bronchial transient secretory cells. EMBO Journal, e105114. http://dx.doi.org/10.15252/embj.20105114

Ma, Y., Xu, Q., Wang, F., Ma, X., Wang, X., Zhang, X., & Zhang, Z. (2020). Characteristics of asymptomatic patients with SARS-CoV-2 infection in Jinan, China. Microbes and Infection, In Press. https://doi.org/10.1016/j.micinf.2020.04.011

Mallapaty, S. (2020). How do children spread the coronavirus? The science still isn't clear. Nature, 581, 127-128. doi: 10.1038/d41586-020-01354-0

McDermott, C. V., Alicic, R. Z., Harden, N., Cox, E. J., Scanlan, J. M. (2020). Put a lid on it: Are faecal bio-aerosols a route of transmission for SARS-CoV-2? The Journal of Hospital Infection, Ahead of print. https://doi.org/10.1016/j.jhin.2020.04.024

Morawska, L. & Cao, J. (2020). Airborne transmission of SARS-CoV-2: the world should face the reality. Environment International, 139, 105730. https://doi.org/10.1016/j.envint.2020.105730

Ong, S., Tan, Y., Chia, P., Lee, T., Ng, O., Wong, M., & Marimuthu, K. (2020). Air, surface environmental, and personal protective equipment contamination by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from a symptomatic patient. JAMA, March 4, 2020. https://doi.org/10.1001/jama.2020.3227

Pollitt, K. J. G., Peccia, J., Ko, A. I., Kaminski, N., Dela Cruz, C. S., Nebert, D. W., Reichardt, J. K. V., Thompson, D. C., & Vasiliou, V. (2020). COVID-19 vulnerability: The potential impact of genetic susceptibility and airborne transmission. Human Genomics, 14, 17. https://doi.org/10.1186/s40246-020-00267-3

Santarpia, J. L., Rivera, D. N., Herrera, V. L., Morwitzer, M. J., Creager, H. M., Santarpia, G. W., Crown, K. K., Brett-Major, D. M., Schnaubelt, E. R., Broadhurst, M. J., Lawler, J. V., Reid, S. P. & Lowe, J. L. (2020). Aerosol and surface contamination of SARS-CoV-2 observed in quarantine and isolation care. Scientific Reports, 5, 10, 12732. https://doi.org/10.1038/s41598-020-69286-3

Sargent, T. H., Muller, W. J., Zheng, X., Rippe, J., Patel, A. B., & Kociolek, L. K. (2020). Age-related differences in nasopharyngeal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) levels in patients with mild to moderate coronavirus disease 2019 (COVID-19). JAMA Pediatrics, 5, July 30. doi: 10.1001/jamapediatrics.2020.3651

Service, R.F. (2020). NAS letter suggests 'normal breathing' can expel coronavirus. Science, 368 (6487), 119. http://dx.doi.org/10.1126/science.368.6487.119

Setti, L., Passarini, F., Gennaro, G. D., Barbieri, P., Perrone, M. G., Borelli, M., Palmisani, J., Gilio, A. D., Pscitelli, P., & Miani, A. (2020). Airborne transmission route of COVID-19: Why 2 meters/6 feet of inter-personal distance could not be enough. International Journal of Environmental Research and Public Health, 17(8), 2932-2932. https://doi.org/10.3390/ijerph17082932

Shia, F., Wua, T., Zhua, X., Gea, Y., Zenga, X., Chia, Y., Duc, X., Zhua, L., Zhua, F., Zhub, B., Cuia, L., & Wu, B. (2020). Association of viral load with serum biomakers among COVID-19 cases. Virology, 546, 122-126. https://doi.org/10.1016/j.virol.2020.04.011

Somsen, G. A., van Rijn, C., Kooij, S., Bem, R. A., & Bonn, D. (2020). Small droplet aerosols in poorly ventilated spaces and SARS-CoV-2 transmission. The Lancet, May 27. https://doi.org/10.1016/S2213-2600(20)30245-9

Stadnytskyi, V., Bax, C. E., Bax, A., & Anfinrud, P. (2020). The airborne lifetime of small speech droplets and their potential importance in SARS-CoV-2 transmission. Proceedings of the National Academy of Sciences, May 13. https://doi.org/10.1073/pnas.2006874117

Sungnak, W., Huang, N., Becavin, C., Berg, M., Queen, R., Litvinukova, M., Talavera-Lopez, C., Maatz, H., Reichart, D., Sampaziotis, F., Worlock, K. B., Yoshida, M., Barnes, J. L., & HCA Lung Biological Network. (2020). SARS-CoV-2 entry factors are highly expressed in nasal epithelial cells together with innate immune genes. Nature Medicine, http://dx.doi.org/10.1038/s41591-020-0868-6

Tang, B., Wang, X., Li, Q., Bragazzi, N. L., Tang, S., Xiao, Y., & Wu, J. (2020). Estimation of the transmission risk of the 2019-nCoV and its implication for public health interventions. Journal of Clinical Medicine, 9(2), 462. https://doi.org/10.3390/jcm9020462

Tian, H., Liu, Y., Li, Y., Wu, C. H., Chen, B., Kraimer, M. U. G., Li, B., Cai, J., Xu, B., Yang, Q., Wang, B., Yang, P., Cui, Y., Song, Y., Zheng, P., Wang, Q., Bjornstad, O. N., Yang, R., Grenfell, B. T., Pybus, O. G., & Dye, C. (2020). An investigation of transmission control measures during the first 50 days of the COVID-19 epidemic in China. Science, eabb6105. https://doi.org/10.1126/science.abb6105

van Doremalen, N., Bushmaker, T., Morris, D. H., Holbrook, M. G., Gamble, A., Williamson, B. N., Tamin, A., Harcourt, J. L., Thornburg, N. J., Gerber, S. I., Lloyd-Smith, J. O., de Wit, E., & Munster, V. J. (2020). Aerosol and surface stability of HCoV-19 (SARS-CoV-2) compared to SARS-CoV-1. The New England Journal of Medicine. https://doi.org/10.1056/NEJMc2004973

Verity, R., Okell, L. C., Dorigatti, I., Winskill, P., Whittaker, C., Imai, N., Cuomo-Dannenburg, G., Thompson, H., Walker, P. G. T., Fu, H., Dighe, A., Griffin, J. T., Baguelin, M., Bhatia, S., Boonyasiri, A., Cori, A., Cucunuba, Z., FitzJohn, R., Gaythorpe, K., Green, W., ... Ferguso, N. M. (2020). Estimates of the severity of coronavirus disease 2019: a model-based analysis. Lancet Infectious Diseases, ahead of print. https://doi.org/10.1016/S1473-3099(20)30243-7

Wilson, N. M., Norton, A., Young, F. P., & Collins, D. W. (2020). Airborne transmission of severe acute respiratory syndrome coronavirus-2 to healthcare workers: a narrative review. Anaesthesia, Ahead of print. https://doi.org/10.1111/anae.15093

Zhang, R., Li, Y., Zhang, A. L., Wang, Y., & Molina M. J. (2020). Identifying airborne transmission as the dominant route for the spread of COVID-19. Proceedings of the National Academy of Sciences, June 11. https://doi.org/10.1073/pnas.2009637117

WHO handwashing protocol.

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Laurie Garrett: Lessons from the 1918 flu.

Disease Progression

COVID-19, initially described as a primarily respiratory illness, has been shown to be a much more far-reaching disease than first realized (Ledford, 2020; Tang, Comish, & Kang, 2020; Wadman et al., 2020). Current research indicates that the serious complications associated with COVID-19 are the result of a dysregulated inflammatory response that impacts organ systems throughout the body (Ledford, 2020; Merad & Martin, 2020; Richardson et al., 2020; Wadman et al., 2020). Specifically, the destructive course of SARS-CoV-2 infections seems to be linked with an inappropriate immune response (Blanco-Melo et al., 2020; Coperchini et al., 2020; McKechnie & Blish, 2020) that results in exuberant production of self-destructive inflammatory proteins called cytokines (Canna & Behrens, 2012; Hirano & Murakami, 2020; Wadman et al., 2020). Even asymptomatic infected individuals show significant organ damage (Long et al., 2020; Oran & Topol, 2020).

COVID-19 patients that do recover have long-term and possibly permanent organ damage (Akhmerov & Marban, 2020; Meng et al., 2020); Wang et al., 2020). The long-term damage in recovered patients includes acute respiratory distress syndrome, heart arrhythmia, myocarditis, kidney abnormalities, and neurological abnormalities like strokes and shifts in consciousness. This long-term damage manifests in patients that were otherwise healthy before COVID-19. Even asymptomatic infected individuals show significant organ damage (Long et al., 2020; Oran & Topol, 2020; Puntmann et al., 2020).

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Lung pathologist, Sanjay Mukhopadhyay, describes the short-term and long-term lung damage from COVID-19.

The Emergency Room Reality of COVID-19 Patients.

Efficacy of Mask Wearing

Masks have been shown to mitigate virus transmission. Current research shows that masks not only protect others from your viral particles but also reduce the viral load that you receive from others (Gandhi, Beyrer, & Goosby, 2020). Research investigating the impact of mask wearing on susceptibility to SARS-CoV-2 shows that wearing a surgical mask reduces the frequency of symptomatic infection (Abaluck et al., 2021). The likelihood of infection is related to viral load (Shia et al., 2020). That is, being exposed to one person that is shedding intact viral particles at a high load is just as effective for transmission as being exposed to multiple individuals shedding at much lower levels (He et al., 2020). How you wear the mask is equally important. Two of the three locations with the densest concentration of the receptor sites for SARS-CoV-2 transmission (ACE2; see Lukassen et al., 2020) are on your face (nose and eyes). If you aren't adequately covering both your nose and mouth, wearing a mask doesn't work.

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Fighting the Virus

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Mitigating the Pandemic

The pandemic will continue as a rolling wave until the majority of the world's population is vaccinated (Kissler et al., 2020; Kwok et al., 2020; Moore et al., 2020). Until the majority of the world's population is vaccinated, social distancing is the most effective solution to slow the spread of SARS-SoV-2 (Cobb and Seale, 2020; Distante, Piscitelli, & Miani, 2020; Kraemer et al., 2020; Sen, Karaca-Mandic, & Georgiou, 2020). In order for this measure to work, it is critical to understand what is meant by social distancing. Social distancing does not mean staying six feet away from someone else.

The control measure of social distancing means avoiding situations that have been demonstrated to facilitate excess virus transmission. Enclosed spaces with groups of people who do not live together are all high risk regardless of whether or not individuals are wearing masks (Tupper et al., 2020). Situations that are referred to as saturating, high transmission settings (high schools, parties, choirs, restaurant kitchens, crowded offices, nightclubs and bars) make it impossible to mitigate virus transmission (Tupper et al., 2020). Research indicates that in the absence of these type of transmission events, the pandemic would likely have never begun (Pekar et al., 2021).

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War reporter W.J. Hennigan describes handling the onslaught of dead COVID-19 victims in New York.