Possible modes of transmission of Novel coronavirus SARS-CoV-2: a review

Possible modes of transmission of Novel coronavirus SARS-CoV-2: a review



SARS-CoV-2; modes of transmission; air-borne; conjunctiva; fecal-oral; maternal-fetal; flatulence (farts); Breast milk


Abstract: Introduction: The widespread outbreak of the novel SARS-CoV-2 has raised numerous questions about the origin and transmission of the virus. Knowledge about the mode of transmission as well as assessing the effectiveness of the preventive measures would aid in containing the outbreak of the coronavirus. Presently, respiratory droplets, physical contact and aerosols/air-borne have been reported as the modes of SARS-CoV-2 transmission of the virus. Besides, some of the other possible modes of transmission are being explored by the researchers, with some studies suggesting the viral spread through fecal-oral, conjunctival secretions, flatulence (farts), sexual and vertical transmission from mother to the fetus, and through asymptomatic carriers, etc. Aim: The primary objective was to review the present understanding and knowledge about the transmission of SARS-CoV-2 and also to suggest recommendations in containing and preventing the novel coronavirus. Methods: A review of possible modes of transmission of the novel SARS-CoV-2 was conducted based on the reports and articles available in PubMed and ScienceDirect.com that were searched using keywords, ‘transmission’, ‘modes of transmission’, ‘SARS-CoV-2’, ‘novel coronavirus’, and ‘COVID-19’. Articles referring to air-borne, conjunctiva, fecal-oral, maternal-fetal, flatulence (farts), and breast milk transmission were included, while the remaining were excluded. Result and Conclusion: The modes of transmission linked to SARS-CoV-2 were identified and the available literature on each of these is described in detail in view of the possibilities of viral transmission through various modes of transmission. The review provides updated and necessary information on the possible modes of transmission for the health care workers and the lay public under one umbrella that can also be considered during framing guidelines in order to prevent and control the viral spread.

Author Biographies

Richa Mukhra, Department of Anthropology (UGC Centre of Advanced Study), Panjab University, Sector-14, Chandigarh, India

PhD Research Scholar, Department of Anthropology (UGC Centre of Advanced Study), Panjab University, Sector-14, Chandigarh, India.

Kewal Krishan, Department of Anthropology (UGC Centre of Advanced Study), Panjab University, Sector-14, Chandigarh, India

Kewal Krishan, PhD, FRAI, FIALFS, FIACME

Department of Anthropology (Biological anthropologist) Panjab University
Chandigarh-160 014
INDIA, Mobile: +91-9876048205
University Profile: http://anthropology.puchd.ac.in/includes/cv/75-krishanantro.pdf Google Scholar Profile: http://scholar.google.co.in/citations?user=CD0Uz8AAAAAJ&hl=en Researchgate Profile: http://www.researchgate.net/profile/Kewal_Krishan6/ Scopus Profile:  http://www.scopus.com/authid/detail.url?authorId=34167945900 PUBMED: http://www.ncbi.nlm.nih.gov/pubmed/?term=krishan+k Wikipedia Profile: https://en.wikipedia.org/wiki/Kewal_Krishan_(forensic_anthropologist)

Tanuj Kanchan, Department of Forensic Medicine and Toxicology, All India Institute of Medical Sciences Jodhpur, India

Dr. Tanuj Kanchan MBBS, DFM, MD
Assistant Dean (Research), 

Department of Forensic Medicine and Toxicology, All India Institute of Medical Sciences, Jodhpur, India.


World Health Organization. Naming the coronavirus disease (COVID-19) and the virus that causes it. World Health Organization. 2020 Feb. Available from: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/technical-guidance/naming-the-coronavirus-disease-(covid-2019)-and-the-virus-that-causes-it. Accessed July 17, 2020.

World Health Organization. WHO Director-General's opening remarks at the media briefing on COVID-19-11 March 2020. Geneva, Switzerland. 2020 Mar. Available from: https://www.who.int/dg/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19---11-march-2020. Accessed July 17, 2020.

World Health Organization. Coronavirus (COVID-19). World Health Organization. 2020. Available from: https://covid19.who.int/. Accessed July 17, 2020.

Weiss SR, Leibowitz JL. Coronavirus pathogenesis. In Advances in virus research 2011 Jan 1 (Vol. 81, pp. 85-164). Academic Press. https://doi.org/10.1016/B978-0-12-385885-6.00009-2.

Yang D, Leibowitz JL. The structure and functions of coronavirus genomic 3′ and 5′ ends. Virus Res 2015;206:120-133. https://doi.org/10.1016/j.virusres.2015.02.025.

Banerjee A, Kulcsar K, Misra V, et al. Bats and coronaviruses. Viruses 2019;11(1):41. https://doi.org/10.3390/v11010041.

World Health Organization. Consensus document on the epidemiology of severe acute respiratory syndrome (SARS). World Health Organization; 2003. https://apps.who.int/iris/handle/10665/70863.

Alanagreh L, Alzoughool F, Atoum M. The Human Coronavirus Disease COVID-19: Its Origin, Characteristics, and Insights into Potential Drugs and Its Mechanisms. Pathogens. 2020;9:331. https://doi:10.3390/pathogens9050331

Lau SK, Li KS, Huang Y, et al. Ecoepidemiology and complete genome comparison of different strains of severe acute respiratory syndrome-related Rhinolophus bat coronavirus in China reveal bats as a reservoir for acute, self-limiting infection that allows recombination events. J Virol 2010;84(6):2808-2819. https://doi.org/10.1128/jvi.02219-09.

Chinese SARS Molecular Epidemiology Consortium. Molecular evolution of the SARS coronavirus during the course of the SARS epidemic in China. Science 2004;303(5664):1666-1669. https://doi.org/10.1126/science.1092002.

Wang LF, Eaton BT. Bats, civets and the emergence of SARS. Curr Top Microbiol Immunol. 2007;315:325-344. https://doi.org/10.1007/978-3-540-70962-6_13.

Müller MA, Corman VM, Jores J, et al. MERS coronavirus neutralizing antibodies in camels, Eastern Africa, 1983–1997. Emerg Infect Dis 2014;20(12):2093. https://doi.org/10.3201/eid2012.141026.

Chu DK, Poon LL, Gomaa MM, et al. MERS coronaviruses in dromedary camels, Egypt. Emerg Infect Dis 2014;20(6):1049. https://doi.org/10.3201/eid2006.140299.

Guo YR, Cao QD, Hong ZS, et al. The origin, transmission and clinical therapies on coronavirus disease 2019 (COVID-19) outbreak–an update on the status. Mil Med Res 2020;7(1):1-10. https://doi.org/10.1186/s40779-020-00240-0.

World Health Organization. SARS (Severe Acute Respiratory Syndrome). World Health Organization. 2020. Available from: https://www.who.int/ith/diseases/sars/en/. Accessed July 11, 2020.

World Health Organization. Modes of transmission of virus causing COVID-19: implications for IPC precaution recommendations. World Health Organization. 2020. https://www.who.int/news-room/commentaries/detail/modes-of-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution-recommendations. (Accessed July 13, 2020).

Li Q, Guan X, Wu P, et al. Early transmission dynamics in Wuhan, China, of novel coronavirus–infected pneumonia. N Engl J Med 2020;382:1199–1207. https://doi.org/10.1056/NEJMoa2001316.

Phan LT, Nguyen TV, Luong QC, et al. Importation and human-to-human transmission of a novel coronavirus in Vietnam. N Engl J Med 2020;382:872-874. https://doi.org/10.1056/NEJMc2001272.

Rothe C, Schunk M, Sothmann P, et al. Transmission of 2019-NCOV infection from an asymptomatic contact in Germany. N Engl J Med 2020;382:970–971. https://doi.org/10.1056/NEJMc2001468.

Signorelli C, Odone A, Riccò M, Bellini L, Croci R, Oradini-Alacreu A, Fiacchini D, Burioni R. Major sports events and the transmission of SARS-CoV-2: analysis of seven case-studies in Europe. Acta Bio Med [Internet]. 2020May11 [cited 2020Jul.14];91(2):242-4. Available from: https://www.mattioli1885journals.com/index.php/actabiomedica/article/view/9699.

Krishan K, Kanchan T. Aerosol and surface persistence: Novel SARS-CoV-2 versus other coronaviruses. J Infec Dev Contri [In Press] 2020.

Pan Y, Zhang D, Yang P, et al. Viral load of SARS-CoV-2 in clinical samples. Lancet Infect Dis 2020;20:411–412. https://doi.org/10.1016/S1473-3099(20)30113-4.

Xu H, Zhong L, Deng J, et al. High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa. Int J Oral Sci 2020;12:1–5. https://doi.org/10.1038/s41368-020-0074-x.

To KKW, Tsang OTY, Chik-Yan Yip C, et al. Consistent detection of 2019 novel coronavirus in saliva. Clin Infect Dis 2020;4–6. https://doi.org/10.1093/cid/ciaa149.

Han P, Ivanovski S. Saliva-Friend and Foe in the COVID-19 Outbreak. Diagnostics (Basel). 2020;10(5):290. https://doi.org/10.3390/diagnostics10050290

Warnes SL, Little ZR, Keevil CW. Human coronavirus 229E remains infectious on common touch surface materials. MBio 2015;6:1–10. https://doi.org/10.1128/mBio.01697-15.

Dowell SF, Simmerman JM, Erdman DD, et al. Severe Acute Respiratory Syndrome Coronavirus on Hospital Surfaces. Clin Infect Dis 2004;39:652–657. https://doi.org/10.1086/422652.

Booth TF, Kournikakis B, Bastien N, et al. Detection of Airborne Severe Acute Respiratory Syndrome (SARS) Coronavirus and Environmental Contamination in SARS Outbreak Units. J Infect Dis 2005;191:1472–1477. https://doi.org/10.1086/429634.

Chinese Preventive Medicine Association. New Group of Experts on the prevention and control of Chinese Preventive Medicine Association coronavirus pneumonia. The latest understanding of the epidemiological characteristics of pneumonia novel coronavirus. [Article in Chinese] Chin J Epidemiol 2020;41:139-144. https://doi.org/10.3760/cma.j.issn.0254-6450.2020.02.002.

van Doremalen N, Bushmaker T, Morris DH, et al. Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1. N Engl J Med 2020;382:1564-1567. https://doi.org/10.1056/NEJMc2004973.

Carraturo F, Del Giudice C, Morelli M, et al. Persistence of SARS-CoV-2 in the environment and COVID-19 transmission risk from environmental matrices and surfaces. Environ Pollut 2020;115010. https://doi.org/10.1016/j.envpol.2020.115010.

Klompas M, Baker MA, Rhee C. Airborne Transmission of SARS-CoV-2: Theoretical Considerations and Available Evidence. JAMA 2020. https://doi.org/10.1001/jama.2020.12458.

Morawska L, Cao J. Airborne transmission of SARS-CoV-2: The world should face the reality. Environ Int 2020;139:105730. https://doi.org/10.1016/j.envint.2020.105730.

Wang D, Hu B, Hu C, et al. Clinical Characteristics of 138 Hospitalized Patients with 2019 Novel Coronavirus-Infected Pneumonia in Wuhan, China. JAMA 2020; 323(11):1061-1069. https://doi.org/10.1001/jama.2020.1585.

Fears AC, Klimstra WB, Duprex P, et al. Persistence of Severe Acute Respiratory Syndrome Coronavirus 2 in Aerosol Suspensions. Emerg Infect Dis 2020;26(9).

Morawska L, Milton DK. It is Time to Address Airborne Transmission of COVID-19. Clin Infect Dis 2020;ciaa939. https://doi.org/10.1093/cid/ciaa939

World Health Organisation. Transmission of SARS-CoV-2: implications for infection prevention precautions. World Health Organisation. 2020. Available from: https://www.who.int/news-room/commentaries/detail/transmission-of-sars-cov-2-implications-for-infection-prevention-precautions (Accessed July 13, 2020).

Yu ITS, Li Y, Wong TW, et al. Evidence of Airborne Transmission of the Severe Acute Respiratory Syndrome Virus. N Engl J Med 2004;350:1731–1739. https://doi.org/10.1056/NEJMoa032867.

Qu G, Li X, Hu L, et al. An Imperative Need for Research on the Role of Environmental Factors in Transmission of Novel Coronavirus (COVID-19). Environ Sci Technol 2020;54(7):3730‐3732. https://doi.org/10.1021/acs.est.0c01102.

Young BE, Ong SWX, Kalimuddin S, et al. Epidemiologic Features and Clinical Course of Patients Infected with SARS-CoV-2 in Singapore. JAMA 2020; 323(15):1488-1494. https://doi.org/10.1001/jama.2020.3204.

Ong SWX, Tan YK, Chia PY, et al. Air, Surface Environmental, and Personal Protective Equipment Contamination by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) from a Symptomatic Patient. JAMA 2020; 323(16):1610-1612. https://doi.org/10.1001/jama.2020.3227.

Liu Y, Ning Z, Chen Y, et al. Aerodynamic characteristics and RNA concentration of SARS-CoV-2 aerosol in Wuhan hospitals during COVID-19 outbreak. bioRxiv 2020;982637 https://doi.org/10.1101/2020.03.08.982637.

Weber DJ, Rutala WA, Fischer WA, et al. Emerging infectious diseases: Focus on infection control issues for novel coronaviruses (Severe Acute Respiratory Syndrome-CoV and Middle East Respiratory Syndrome-CoV), hemorrhagic fever viruses (Lassa and Ebola), and highly pathogenic avian influenza viruses, A(H5N1) and A(H7N9). Am J Infect Control 2016;44:E91−E100. https://doi.org/10.1016/j.ajic.2015.11.018.

Amirian ES. Potential fecal transmission of SARS-CoV-2: current evidence and implications for public health. Int J Infect Dis 2020 Apr 23. https://doi.org/10.1016/j.ijid.2020.04.057.

Casanova L, Rutala WA, Weber DJ, et al. Survival of surrogate coronaviruses in water. Water Res. 2009;43:1893–1898. https://doi.org/10.1016/j.watres.2009.02.002.

Heller L, Mota CR, Greco DB. Science of the Total Environment COVID-19 faecal-oral transmission : Are we asking the right questions ? Sci Total Environ 2020;729:138919. https://doi.org/10.1016/j.scitotenv.2020.138919.

Zhu Z, Liu Y, Xu L, et al. Extra-pulmonary viral shedding in H7N9 Avian Influenza patients. J Clin Virol 2015;69:30–32. https://doi.org/10.1016/j.jcv.2015.05.013.

Xu Y, Li X, Zhu B, et al. Characteristics of pediatric SARS-CoV-2 infection and potential evidence for persistent fecal viral shedding. Nat Med 2020;26:502–505. https://doi.org/10.1038/s41591-020-0817-4.

Chen Y, Chen L, Deng Q, et al. The Presence of SARS-CoV-2 RNA in Feces of COVID-19 Patients. J Med Virol 2020;10.1002/jmv.25825. https://doi.org/10.1002/jmv.25825.

Xiao F, Tang M, Zheng X, et al. Evidence for gastrointestinal infection of SARS-CoV-2. Gastroenterology 2020;158(6):1831-1833.e3. https://doi.org/10.1053/j.gastro.2020.02.055.

Holshue ML, DeBolt C, Lindquist S, et al. First case of 2019 novel coronavirus in the United States. N Engl J Med 2020;382:929–936. https://doi.org/10.1056/NEJMoa2001191.

Zhang T, Cui X, Zhao X, et al. Detectable SARS‐CoV‐2 Viral RNA in Feces of Three Children during Recovery Period of COVID‐19 Pneumonia. J Med Virol 2020; 10.1002/jmv.25795. https://doi.org/10.1002/jmv.25795.

Wu Y, Guo C, Tang L, et al. Prolonged presence of SARS-CoV-2 viral RNA in faecal samples. The Lancet Gastroenterol Hepatol 2020;5:434-435. https://doi.org/10.1016/S2468-1253(20)30083-2.

Cheung KS, Hung IF, Chan PP, et al. Gastrointestinal Manifestations of SARS-CoV-2 Infection and Virus Load in Fecal Samples from the Hong Kong Cohort and Systematic Review and Meta-analysis. Gastroenterology 2020;S0016-5085(20)30448-0. https://doi.org/10.1053/j.gastro.2020.03.065.

DNA Web Team. Coronavirus spreading through farts? Here is what experts say. 2020 Available from: https://www.dnaindia.com/world/photo-gallery-coronavirus-spreading-through-farts-here-is-what-experts-say-2821809. Accessed July 11, 2020.

Global Times. Do farts spread novel coronavirus? A Beijing district CDC answers. 2020. https://www.globaltimes.cn/content/1180514.shtml Accessed July 11, 2020.

Naicker S, Yang CW, Hwang SJ, et al. The Novel Coronavirus 2019 epidemic and kidneys. Kidney Int 2020;97:824–828. https://doi.org/10.1016/j.kint.2020.03.001.

Patrì A, Gallo L, Guarino M, et al. Sexual transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): A new possible route of infection? J Am Acad Dermatol 2020; 82(6):e227. https://doi.org/10.1016/j.jaad.2020.03.098.

Peng X, Xu X, Li Y, et al. Transmission routes of 2019-nCoV and controls in dental practice. Int J Oral Sci 2020;12(1):9. https://doi.org/10.1038/s41368-020-0075-9.

Xu J, Qi L, Chi X, et al. Orchitis: A Complication of Severe Acute Respiratory Syndrome (SARS)1. Biol Reprod 2006;74:410–416. https://doi.org/10.1095/biolreprod.105.044776.

Wang Z, Xu X. scRNA-seq Profiling of Human Testes Reveals the Presence of the ACE2 Receptor, A Target for SARS-CoV-2 Infection in Spermatogonia, Leydig and Sertoli Cells. Cells 2020;9:920. https://doi.org/10.3390/cells9040920.

Dong L, Tian J, He S, et al. Possible Vertical Transmission of SARS-CoV-2 from an Infected Mother to Her Newborn. JAMA 2020;323(18):1846-1848. https://doi.org/10.1001/jama.2020.4621.

Woo PCY, Lau SKP, Wong BHL, et al. Detection of Specific Antibodies to Severe Acute Respiratory Syndrome (SARS) Coronavirus Nucleocapsid Protein for Serodiagnosis of SARS Coronavirus Pneumonia. J Clin Microbiol 2004;42:2306–2309. https://doi.org/10.1128/JCM.42.5.2306-2309.2004.

Cao Q, Chen YC, Chen CL, et al. SARS-CoV-2 infection in children: Transmission dynamics and clinical characteristics. J Formos Med Assoc 2020;119:670-673. https://doi.org/10.1016/j.jfma.2020.02.009.

Chen H, Guo J, Wang C, et al. Clinical characteristics and intrauterine vertical transmission potential of COVID-19 infection in nine pregnant women: a retrospective review of medical records. Lancet 2020;395:809–815. https://doi.org/10.1016/S0140-6736(20)30360-3.

Groß R, Conzelmann C, Müller J, et al. Detection of SARS-CoV-2 in Human Breast Milk. Lancet. 2020;395:1757-1758. https://doi.org/10.1016/S0140-6736(20)31181-8.

Schwartz DA. An Analysis of 38 Pregnant Women with COVID-19, Their Newborn Infants, and Maternal-Fetal Transmission of SARS-CoV-2: Maternal Coronavirus Infections and Pregnancy Outcomes. Arch Pathol Lab Med 2020;10.5858/arpa.2020-0901-SA. https://doi.org/10.5858/arpa.2020-0901-SA.

Elkafrawi D, Joseph J, Schiattarella A, et al. Intrauterine transmission of COVID-19 in Pregnancy: case report and review of literature. Acta Bio Med [Internet]. 2020May28 [cited 2020Jul.14];91(3). Available from: https://www.mattioli1885journals.com/index.php/actabiomedica/article/view/9795

Olofsson S, Kumlin U, Dimock K, et al. Avian influenza and sialic acid receptors: more than meets the eye? Lancet Infect Dis 2005;5:184–188. https://doi.org/10.1016/s1473-3099(05)01311-3.

Peiris JS, Yuen KY, Osterhaus AD, et al. The severe acute respiratory syndrome. N Engl J Med 2003;349:2431–2441. https://doi.org/ 10.1056/NEJMra032498.

Belser JA, Rota PA, Tumpey TM. Ocular Tropism of Respiratory Viruses. Microbiol Mol Biol Rev 2013;77:144–156. https://doi.org/10.1128/mmbr.00058-12.

Sun C, Wang Y, Liu G, et al. Role of the eye in transmitting human coronavirus: What we know and what we Do not know. Front Public Health 2020;8:155. https://doi.org/10.3389/fpubh.2020.00155.

Lu C, Liu X, fen Jia, et al. 2019-nCoV transmission through the ocular surface must not be ignored. Lancet 2020;395:e39. https://doi.org/10.1016/S0140-6736(20)30313-5.

Xia J, Tong J, Liu M, et al. Evaluation of coronavirus in tears and conjunctival secretions of patients with SARS-CoV-2 infection. J Med Virol 2020; 10.1002/jmv.25725. https://doi.org/10.1002/jmv.25725.

Ye F, Xu S, Rong Z, et al. Delivery of infection from asymptomatic carriers of COVID-19 in a familial cluster. Int J Infect Dis 2020;94:133–138. https://doi.org/10.1016/j.ijid.2020.03.042.

Chan JFW, Yuan S, Kok KH, et al. A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster. Lancet 2020;395:514–523. https://doi.org/10.1016/S0140-6736(20)30154-9.

Kuperferschmidt K. Study claiming new coronavirus can be transmitted by people without symptoms was flawed. Science 2020. Available from: https://www.sciencemag.org/news/2020/02/paper-non-symptomatic-patient-transmitting-coronavirus-wrong#. Accessed July 11, 2020.

Kinnear J. Asymptomatic Covid-19 patients can still develop lung damage. The Print 2020. Available from: https://theprint.in/health/asymptomatic-covid-19-patients-can-still-develop-lung-damage/449337/. Accessed July 13, 2020.

The Novel Coronavirus Pneumonia Emergency Response Epidemiology Team. Vital surveillances: the epidemiological characteristics of an outbreak of 2019 novel coronavirus diseases (COVID-19)—China,2020. China CDC Weekly 2020;2(8):113-122. https://doi.org/10.46234/ccdcw2020.032.







How to Cite

Mukhra R, Krishan K, Kanchan T. Possible modes of transmission of Novel coronavirus SARS-CoV-2: a review. Acta Biomed [Internet]. 2020 Sep. 7 [cited 2024 Jul. 22];91(3):e2020036. Available from: https://www.mattioli1885journals.com/index.php/actabiomedica/article/view/10039