As an infectious disease physician who had the privilege of caring for many patients during the unsettling times of the early HIV epidemic and the more recent H1N1 pandemic influenza, I fully understand the widespread anxiety the current Covid-19 pandemic has inflicted on our society.
Here are 5 scientific facts that may be worth remembering as we try to deal with our pandemic anxiety.
1. On transmission in the community: For sure, Covid-19 is transmitted in the community but I am glad that it behaves more like influenza which is primarily contracted through close personal contact and droplets, and less like measles or chickenpox which are considered airborne with viral particles travelling lingering in the air for long periods of time. On average, a patient with Covid-19 may infect 2-3 susceptible contacts vs as many as 12 or more in the case of patients with measles or chickenpox (1, 2).
2. On transmission in healthcare settings: For sure, Covid-19 can be transmitted in the healthcare settings, just like other coronaviruses, such severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS) coronaviruses. But the good news is that, in the absence of aerosol-producing procedures (eg, intubation, nebulizer therapy) it doesn’t seem to behave like an airborne virus (see above) and adherence to droplet and contact precautions, including donning of masks, gowns, eye protection and hand hygiene has been effective (3, 4).
3. On surface viability after cleaning/disinfection: For sure, the novel 2019 coronavirus SARS-CoV-2, the cause of Covid-19, can be found on surfaces outside of the body. But the good news is that, in contrast to hardy viruses such as norovirus, it succumbs to common disinfection and environmental cleaning procedures. That’s because coronaviruses have a lipid envelope that easily falls apart under usual cleaning and disinfection of surfaces. That means that simple handwashing with soap and water (minimum 20 seconds), alcohol containing hand hygiene products, detergents and diluted bleach should easily inactivate it (5-9) and that’s good!
4. On the course of Covid-19: For sure, Covid-19 can make people very sick and, tragically, may be fatal on occasion. But compared to diseases caused by other recent respiratory coronaviruses such as MERS or SARS, the overall mortality associated with Covid-19 is much lower (often ~ 2.0-3.0% or lower vs 36.0% for MERS and ~10.0% for SARS) (1). In fact, the majority of patients (~80%) may have no symptoms or only have mild disease (10). I am thankful that we are not dealing with a transmissible respiratory virus that has mortality rates like that of MERS.
5. On the timing of this pandemic: We are fortunate that this is 2020 not 1918-19 when a particularly virulent form of influenza, dubbed as “the mother of all pandemics” infected some 500 million people (a third of the world’s population at the time) and accounted for an estimated 50 million deaths (11). Imagine fighting a pandemic without the technology to identify its cause. Imagine fighting a pandemic without access to the miracles of modern science and medicine, including antibiotics for secondary bacterial pneumonia, artificial ventilation, dialysis, ICU support, and capability to screen for an infectious agent. Imagine fighting a pandemic without scientific tools to develop effective antimicrobials or vaccines. Imagine fighting a pandemic without the luxury of the internet.
As unprepared as we all feel in combatting Covid-19, I take solace in the fact that our armamentarium and collective determination to mount an effective response to this pandemic has never been better. Even during these uncertain times, I reflect on what could have been and remain optimistic. Be safe!
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1. Fauci AS, Lane HC, Redfield RR. Covid-19—Navigating the uncharted. N Eng J Med 2020. DOI:10.1056/NEJMe2002387. https://www.nejm.org/doi/full/10.1056/NEJMe2002387
2. Delamater PL, Street EJ, Leslie TF, et al. Complexity of the basic reproduction number (R0). Emerg infect Dis 2019;25:1-4. https://wwwnc.cdc.gov/eid/article/25/1/17-1901_article
3. Seto WH, Tsang D, Yung RWH, et al. Effectiveness of precautions against droplets and contact in prevention of nosocomial transmission of severe acute respiratory syndrome (SARS). Lancet 2003;361:1519-20. https://www.sciencedirect.com/science/article/pii/S0140673603131686
4. Ng K, Poon BH, Puar THK, et al. COVID-19 and the risk to health care workers: a case report. Ann Intern Med. 2020, March 16. https://annals.org/aim/fullarticle/2763329/covid-19-risk-health-care-workers-case-report
5. van Doremalen N, Bushmaker, Morris DH, et al. Aerosol and surface stability of HCoV-19 (SARS-CoV-2) compared to SARS-CoV-1. N Engl J Med 2020. https://doi.org/10.1101/2020.03.09.20033217
6. Kampf G. Efficacy of ethanol against viruses in hand disinfection. J Hosp Infect 2018;98:331-38. https://www.sciencedirect.com/science/article/pii/S0195670117304693
7. Grayson ML, Melvani S, Druce J, et al. Efficacy of soap and water and alcohol-based hand-rub preparations against live H1N1 influenza virus on the hands of human volunteers Clin Infect Dis 2009;48:285-91. https://www.ncbi.nlm.nih.gov/pubmed/19115974/
8. Service RF. Does disinfecting surfaces really prevent the spread of coronavirus? Science 2020, March 12. https://www.sciencemag.org/news/2020/03/does-disinfecting-surfaces-really-prevent-spread-coronavirus
9. CDC. Norovirus. https://www.cdc.gov/vitalsigns/norovirus/index.html
10. Guan W, Ni Z, Hu Y, et al. Clinical characteristics of Coronavirus disease 2019 in China. N Engl J Med 2020. First published Feb 28, 220, last updated March 6, 2020. https://www.nejm.org/doi/10.1056/NEJMoa2002032
11. Taubenberger JK, Morens DM. 1918 influenza: the mother of all pandemics. Emerg Infect Dis 2006;12:15-22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3291398/
Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!