Libyan Journal of Medical Sciences

: 2020  |  Volume : 4  |  Issue : 2  |  Page : 52--57

Coronavirus disease 2019: The story so far

Ali S Omrani 
 Communicable Diseases Center, Hamad Medical Corporation; Department of Medicine, Division of Infectious Diseases, Hamad Medical Corporation, Doha, Qatar

Correspondence Address:
Dr. Ali S Omrani
Communicable Diseases Center, Hamad Medical Corporation, PO Box 3050, Doha


Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) emerged in China in late 2019 and became a global pandemic by March 2020. SARS-CoV-2 is a highly transmissible virus that causes a clinical illness known as Coronavirus Disease 2019. The clinical spectrum ranges from mild respiratory and generalized symptoms to severe pneumonia with multiple organ failure. Overall mortality is high in older patients and those with comorbidities such as obesity and cardiovascular disease. Diagnosis is usually confirmed by polymerase chain reaction on upper or lower airway samples. Clinical management is largely supportive; no specific therapeutic options are currently available. Public health interventions have thus far been centered around social distancing, large-scale testing, and isolation. An unprecedent global effort has been mounted for the rapid development of effective SARS-CoV-2 vaccines. Until such time, further waves of SARS-CoV-2 are likely, if the restrictive control measures are removed.

How to cite this article:
Omrani AS. Coronavirus disease 2019: The story so far.Libyan J Med Sci 2020;4:52-57

How to cite this URL:
Omrani AS. Coronavirus disease 2019: The story so far. Libyan J Med Sci [serial online] 2020 [cited 2022 Sep 27 ];4:52-57
Available from:

Full Text


Public health officials in Hubei Province in China became aware of a cluster of undiagnosed pneumonia in Wuhan city in November and December 2019. In January 2020, the cause was identified as a novel betacoronavirus that had most probably emerged in a wet market in the city.[1],[2] The virus was subsequently named Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) and the disease it caused as Coronavirus Disease 2019 (COVID-19).[3] Herein is a summary of salient virologic, epidemiologic, and clinical features of COVID-19.


SARS-CoV-2 is genetically distinct from previously known human betacoronaviruses, including SARS-CoV and MERS-CoV.[4],[5],[6] Although not confirmed yet, it is likely that SARS-CoV-2 originated in bats before it was transmitted to humans directly or through an intermediate host.[4],[7] Like other human coronaviruses, SARS-CoV-2 is an enveloped, positive-sense, single-stranded RNA virus. Its genome encodes four major structural proteins: the spike (S) protein, nucleocapsid (N) protein, membrane (M) protein, and the envelope (E) protein, all of which are essential for its structure.[8] Viral attachment and entry into its host cells are mediated by a cellular Transmembrane Serine Protease (TMPRSS2) that primes the S1 unit of the viral S protein to facilitate binding to its cellular receptor, angiotensin-converting enzyme 2.[9]

 Transmission and Epidemiology

The incubation period is typically 4–5 days but can be anywhere between 2 and 14 days.[2],[10],[11] SARS-CoV-2 is thought to be primarily transmissible via droplets and fomites.[12] Viable SARS-CoV-2 has been recovered from multiple surfaces around infected patients, including from furniture and a toilet seat.[13] Under certain conditions, SARS-CoV-2 may survive in the environment for extended periods. Viable virus was recovered after >20 h from copper and cardboard surfaces and nearly 80 h from stainless steel and plastic surfaces.[14] Although viable SARS-CoV-2 has also been recovered from aerosols, airborne transmissibility remains uncertain.[12],[14] Health-care workers, especially those with overwhelming workloads or in settings where personal protective equipment supply is limited, are at significant risk of SARS-CoV-2 infection. In some reports, health-care staff members constituted up to 10% of all COVID-19 patients.[15],[16],[17],[18],[19]

SARS-CoV-2 is highly transmissible among humans, including documented incidents of transmission from individuals with very mild or no symptoms.[15],[20],[21],[22],[23] The outbreak rapidly expanded across China and nearby countries.[15],[17],[21],[24] Travel facilitated the spread of SARS-CoV-2 to all continents, with numerous countries reporting self-sustained local transmission.[25],[26] On March 11, 2020, the World Health Organization (WHO) declared a SARS-CoV-2 pandemic.[27] By early March 2020, the rate of new SARS-CoV-2 infections declined substantially in China but continued to rise in Western Europe and North America.[28],[29] The exponential transmission potential of SARS-CoV-2 is self-evident. On January 21, 2020, the WHO reported a global total of 314 COVID-19 cases and 6 deaths.[30] Number of cases increased to nearly 78 thousands and more than 2 thousand deaths by February 22, 2020, and to more than 290 thousands and nearly 13 thousand deaths by March 22, 2020.[31],[32] By April 22, 2020, the total number of cases was a staggering 2.5 million, with approximately 170 thousand deaths.[33] The largest numbers of COVID-19 deaths have been reported from the United States of America, Italy, Spain, France, and the United Kingdom. However, the numbers are currently increasing at alarming rates in India, Latin America, and Africa as well.[32],[33]

 Clinical Features and Outcomes

In the majority of patients, COVID-19 is a mild illness characterized by pharyngeal pain, dry cough, fatigue, and fever.[2],[34],[35],[36],[37],[38] A small proportion of patients may experience gastrointestinal symptoms, including nausea, vomiting, and diarrhea.[16],[34],[37],[38] Common laboratory abnormalities include lymphopenia, thrombocytopenia, and high CRP.[16],[34],[36],[37],[38] Plain X-rays are abnormal in approximately 60% of patients, while computed tomography scans show ground-glass opacities and patchy infiltrates in >85% of cases.[37],[39] Moderate-to-severe pneumonia occurs in 15%–20% of patients and is usually associated with shortness of breath and more extensive radiological infiltrates.[34],[37],[38] Around 5%–10% of COVID-19 patients may develop severe pneumonia with hypoxia, acute respiratory distress syndrome, and multi-organ failure. Such patients require admission to an intensive care unit for critical support and mechanical ventilation.[34],[37],[38],[40],[41],[42] Interestingly, severe COVID-19 is associated with excessive production of pro-inflammatory cytokines, akin to cytokine storm syndrome.[16],[38],[43] Moreover, autopsy examination of lungs from COVID-19 patients showed extensive alveolar edema, proteinaceous exudate, and patchy inflammatory cellular infiltration.[44],[45] It has, therefore, been suggested that the pulmonary pathology associated with severe COVID-19 is, in large part, secondary to a dysregulated host immune response.[46],[47]

Children constitute only a small proportion of all COVID-19 patients, and their illness is typically mild or asymptomatic.[48],[49] On the other hand, COVID-19 is more likely to be severe in those with multiple comorbidities.[25],[42] Older age, especially those >70 years, systemic hypertension, obesity, and diabetes mellitus, are particularly important risk factors for severe COVID-19 and mortality.[26],[34],[41],[42],[50],[51]

Pregnancy does not seem to be associated with a higher risk of severe COVID-19.[52],[53],[54] In fact, mild and even asymptomatic COVID-19 has been reported in pregnant women in their third trimester and among those routinely screened at delivery.[52],[54] While some studies did not find evidence of vertical transmission of SARS-CoV-2,[53],[54],[55] others reported high levels of SARS-CoV-2 IgM with elevated blood interleukin (IL)-6 levels in neonates born to mothers with COVID-19.[56],[57] One report described three symptomatic neonates with polymerase chain reaction (PCR)-confirmed SARS-CoV-2 infection.[58]

The reported overall case fatality rates (CFR) associated with COVID-19 range from 0.9% in South Korea and 2.3% in China, to as high as 7.2% in Italy.[15],[34],[50] However, the age composition of COVID-19 patients reported from different countries and the prevalence of underlying comorbidities are probably important drivers of the wide variations in CFRs from one geographic setting to another.[42],[50]

 Laboratory Diagnosis

The diagnosis of COVID-19 can be confirmed by the detection of SARS-CoV-2 using real-time PCR (RT-PCR) assays of upper or lower respiratory tract samples.[59] The highest RT-PCR sensitivity rates are obtained from bronchoalveolar lavage fluid specimens (93%), followed by sputum (72%), nasal swabs (63%), bronchial brush biopsies (46%), and pharyngeal swabs (32%).[60] SARS-CoV-2 has also be detected in saliva specimens (11 out of 12, 92%), stool (44 out of 153, 29%), and blood (3 out of 307, 1%).[60],[61] SARS-CoV-2 viral load in upper airway specimens is highest during the first week after onset of COVID-19 symptoms and declines over time.[62],[63],[64] High SARS-CoV-2 viral loads have been detected in nasal and pharyngeal samples from asymptomatic or mildly symptomatic individuals, supporting the view that such individuals play a an important role in sustaining SARS-CoV-2 transmission.[63],[65],[66] In the majority of patients, viral shedding in the upper airways ceases within 14 days of symptom onset. However, the virus may continue to detected for several weeks, especially in patients with severe COVID-19.[17],[62],[63],[67] It is important to emphasize that all reports thus far of late detection of SARS-CoV-2 in various sample types are based on RT-PCR assays, not viral cultures. It is, therefore, not clear to what extent, if any, does prolonged viral shedding contribute to COVID-19 epidemiology.[17],[68]

Most health-care authorities de-isolate COVID-19 patients if two consecutive upper airway specimens, taken ≥24 h apart, are negative for SARS-CoV-2, in addition to the resolution of signs and symptoms of infection in those who were symptomatic. In addition, the Italian Ministry of Health criteria for virus clearance is documented appearance of SARS-CoV-2 specific IgG.[68] SARS-CoV-2 serological assays could provide a better understanding of the extent of asymptomatic or mildly symptomatic infections that may have gone undetected with molecular diagnostic methods.[68],[69] In one study, sera from 23 patients with laboratory-confirmed COVID-19 were tested by enzyme immuno assay for SARS-CoV-2 nucleoprotein (NP) and spike protein receptor-binding domain (RBD) IgM and IgG. By 14 days from symptoms onset, the rate of detectable antibodies was anti-NP IgM 88%, anti-NP IgG 94%, anti-RBD IgM 94%, and anti-RBD IgG 100%.[62] It is nevertheless important to emphasize that it is unknown at present if the presence of SARS-CoV-2 antibodies can be considered as reliable evidence of immunity against re-infection. Moreover, there are currently no validated, commercially available serological assays for use in routine diagnostic laboratories.[70]

 Clinical Management

The management of patients with COVID-19 is principally supportive.[71],[72],[73] Key elements are the meticulous implementation of infection prevention and control precautions and symptom relief using antipyretics and simple pain killers.[74] Those with severe disease usually require supplemental oxygen, judicious fluid balance, circulatory support, and antibiotics for secondary infections.[72],[74]

There are currently no approved therapeutic options for COVID-19, but a number of potentially useful antiviral agents are in clinical development.[75],[76] Among the promising options is remdesivir, a nucleotide analog inhibitor of SARS-CoV-2 RNA-dependent RNA polymerase.[77] Early data from observational, noncomparative studies appear encouraging, but results from ongoing randomized trials will provide a more reliable assessment of its safety and efficacy in the treatment of patients with COVID-19.[78],[79],[80]

Lopinavir-ritonavir, an HIV protease inhibitor, is known to havein vitro activity against coronaviruses, including SARS, MERS-CoV, and SARS-CoV-2.[81] However, a recent randomized clinical trial did not show benefit with lopinavir-ritonavir in comparison with standard care in terms of viral clearance, time to clinical improvement, or all-cause mortality. Furthermore, adverse event-related discontinuation was seen in 14% of lopinavir-ritonavir patients.[82] Another potential therapeutic approach is the use of protease inhibitors such as nafamostat mesylate to inhibit TMPRSS2-mediated SARS-CoV-2 viral attachment and fusion.[83]

Chloroquine, and the chemically related hydroxychloroquine, possessin vitro activity against SARS-CoV-2.[77],[81] Results from small studies with considerable methodological flaws are conflicting.[72],[73],[76] Both agents are associated with potentially serious cardiotoxicity, especially QT prolongation.[76] Therefore, current guidelines encourage that these agents are used only within clinical trials and with very careful monitoring.[71-73,84]

The well-characterized cytokine-mediated severe manifestations of COVID-19 led to an interest in immune-modulating agents as potential adjunctive therapies.[46],[47] IL-6 inhibitors (e.g.; tocilizumab and sarilumab), Janus kinase inhibitors (e.g.; tofacitinib and ruxolitinib), tumor necrosis factor inhibitors (e.g.; adalimumab) and antiangiogenics (e.g.; bevacizumab) are all currently undergoing evaluation in clinical trials to assess their role in the management of patients with severe COVID-19.[80]

Finally, there has been immense interest in the potential use of convalescent plasma from recovered COVID-19 patients for the treatment of those with severe SARS-CoV-2 infection.[85] As mentioned above, it is not yet clear if and when those who recover from COVID-19 develop neutralizing SARS-CoV-2 antibodies, or whether such antibodies are produced in adequate concentrations to enable useful deployment of convalescent plasma as therapy.[86] The published literature is currently limited to small case series with some suggestions of clinical response.[87],[88] At present, convalescent plasma can only be considered investigational therapy for COVID-19.

 How Will it End?

The public health efforts to control SARS-CoV-2 have included various combinations of travel restrictions, social distancing interventions, proactive testing, and isolation of all confirmed and suspected cases and comprehensive contact tracing and screening, with varying degrees of success from one country to another.[89],[90],[91] There is, however, constant concern that relaxation of the more strict control measures could result in further waves of SARS-CoV-2 infections, potentially more serious than the initial epidemic.[92] An unprecedented effort is currently underway to develop an effective SARS-CoV-2 vaccine, with some candidates already in phase I human studies.[93] It may well be that the pandemic will not be truly controlled until effective vaccines become available, and a majority of the global population has become immune.[94] Bleak, as this forecast might seem, this virus has proven itself to be a challenge of historic magnitude. It will take a historic effort to develop and disseminate effective vaccination in record times to counter.[95]

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


1Zhu N, Zhang D, Wang W, Li X, Yang B, Song J, et al. A novel coronavirus from patients with pneumonia in China, 2019. N Engl J Med 2020;382:727-33.
2Li Q, Guan X, Wu P, Wang X, Zhou L, Tong Y, et al. Early transmission dynamics in Wuhan, China, of novel coronavirus-infected pneumonia. N Engl J Med 2020;382:1199-207.
3Gorbalenya AE, Baker SC, Baric RS, de Groot RJ, Drosten C, Gulyaeva AA, et al. The species Severe acute respiratory syndrome-related coronavirus: Classifying 2019-nCoV and naming it SARS-CoV-2. Nat Microbiol 2020;5:536-44.
4Andersen KG, Rambaut A, Lipkin WI, Holmes EC, Garry RF. The proximal origin of SARS-CoV-2. Nat Med 2020;26:450-2.
5Drosten C, Günther S, Preiser W, van der Werf S, Brodt HR, Becker S, et al. Identification of a novel coronavirus in patients with severe acute respiratory syndrome. N Engl J Med 2003;348:1967-76.
6Zaki AM, van Boheemen S, Bestebroer TM, Osterhaus AD, Fouchier RA. Isolation of a novel coronavirus from a man with pneumonia in Saudi Arabia. N Engl J Med 2012;367:1814-20.
7Zhou P, Yang XL, Wang XG, Hu B, Zhang L, Zhang W, et al. A pneumonia outbreak associated with a new coronavirus of probable bat origin. Nature 2020;579:270-3.
8Lu R, Zhao X, Li J, Niu P, Yang B, Wu H, et al. Genomic characterisation and epidemiology of 2019 novel coronavirus: Implications for virus origins and receptor binding. Lancet 2020;395:565-74.
9Hoffmann M, Kleine-Weber H, Schroeder S, Krüger N, Herrler T, Erichsen S, et al. SARS-CoV-2 cell entry depends on ACE2 and TMPRSS2 and is blocked by a clinically proven protease inhibitor. Cell 2020;181:271-80.
10Backer JA, Klinkenberg D, Wallinga J. Incubation period of 2019 novel coronavirus (2019-nCoV) infections among travellers from Wuhan, China, 20-28 January 2020. Euro Surveill 2020;25:pii 2000062.
11Lauer SA, Grantz KH, Bi Q, Jones FK, Zheng Q, Meredith HR, et al. The incubation period of coronavirus disease 2019 (COVID-19) from publicly reported confirmed cases: Estimation and application. Ann Intern Med 2020;172:577-82.
12World Health Organization. Infection Prevention and Control During Health Care when Novel Coronavirus (nCoV) Infection is Suspected; Interim Guidance. Geneva, Switzerland: World Health Organization; 2020. Available from: [Last updated on 2020 Mar 20].
13Ong SW, Tan YK, Chia PY, Lee TH, Ng OT, Wong MSY, 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;323:1610-2.
14van Doremalen N, Bushmaker T, Morris DH, Holbrook MG, Gamble A, Williamson BN, et al. Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1. N Engl J Med 2020;382:1564-7.
15Shim E, Tariq A, Choi W, Lee Y, Chowell G. Transmission potential and severity of COVID-19 in South Korea. Int J Infect Dis 2020;93:339-44.
16Wang D, Hu B, Hu C, Zhu F, Liu X, Zhang J, et al. Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected pneumonia in Wuhan, China. JAMA 2020;323:1061-9.
17World Health Organization. Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19). Geneva, Switzerland: World Health Organization; 2020. Available from: [Last accessed on 2020 May 09].
18Istituto Superiore di Sanità. Sorveglianza Integrata COVID-19 in Italia: Aggriornamento 2020. Available from: [Last accessed on 2020 May 09].
19CDC COVID-19 Response Team. Characteristics of health care personnel with COVID-19-United States, February 12-April 9, 2020. MMWR Morb Mortal Wkly Rep 2020;69:477-81.
20Rothe C, Schunk M, Sothmann P, Bretzel G, Froeschl G, Wallrauch C, et al. Transmission of 2019-nCoV infection from an asymptomatic contact in Germany. N Engl J Med 2020;382:970-1.
21Bai Y, Yao L, Wei T, Tian F, Jin DY, Chen L, et al. Presumed asymptomatic carrier transmission of COVID-19. JAMA 2020;323:1406-7.
22Phan LT, Nguyen TV, Luong QC, Nguyen TV, Nguyen HT, Le HQ, et al. Importation and human-to-human transmission of a novel coronavirus in Vietnam. N Engl J Med 2020;382:872-4.
23Yu P, Zhu J, Zhang Z, Han Y, Huang L. A familial cluster of infection associated with the 2019 novel coronavirus indicating potential person-to-person transmission during the incubation period. J Infect Dis 2020;pii:jiaa077. doi: 10.1093/infdis/jiaa077.
24Pongpirul WA, Pongpirul K, Ratnarathon AC, Prasithsirikul W. Journey of a Thai taxi driver and novel coronavirus. N Engl J Med 2020;382:1067-8.
25Grasselli G, Pesenti A, Cecconi M. Critical care utilization for the COVID-19 outbreak in Lombardy, Italy: Early experience and forecast during an emergency response. JAMA 2020;323:1545-1546.
26Richardson S, Hirsch JS, Narasimhan M, Crawford JM, McGinn T, Davidson KW, et al. Presenting characteristics, comorbidities, and outcomes among 5700 patients hospitalized with COVID-19 in the New York city area. JAMA 2020. doi: 10.1001/jama.2020.6775.
27World Health Organization. Coronavirus disease 2019 (COVID-19) Situation Report 51 – 11 March 2020 Geneva, Switzerland: World Health Organization; 2020. Available from: [Last accessed on 2020 May 09].
28European Centre for Disease Prevention and Control. Rapid Risk Assessment: Coronavirus Disease 2019 (COVID-19) Pandemic: Increased Transmission in the EU/EEA and the UK; 7th update 2020. Available from: [Last accessed 2020 May 09].
29World Health Organization. Coronavirus disease 2019 (COVID-19) Situation Report 65 – 25 March 2020: World Health Organization; 2020. Available from: sn=2b74edd8_2. [Last accessed on 2020 May 09].
30World Health Organization. Novel Coronavirus (2019-nCoV) Situation Report 2 – 22; January 2020. Available from: [Last accessed on 2020 May 09].
31World Health Organization. Coronavirus disease (COVID-2019) Situation Report 33 – 22 February 2020. Geneva: World Health Organization; 2020. Available from: urce/coronaviruse/situation-reports/20200222-sitrep-33-covid-19.pdf?sfvrsn=c9585c8f_4. [Last accessed on 2020 May 09].
32World Health Organization. Coronavirus Disease 2019 (COVID-19) Situation Report 62; 22 March 2020. Available from: p-62-covid-19.pdf?sfvrsn=755c76cd_2. [Last accessed on 2020 May 09].
33World Health Organization. Coronavirus Disease (COVID-2019) Situation Report 93 – 22 April 2020. Geneva: World Health Organization; 2020. Available from: ult-source/coronaviruse/situation-reports/20200422-sitrep-93-covi d-19.pdf?sfvrsn=35cf80d7_4. [Last accessed on 2020 May 09].
34Wu Z, McGoogan JM. Characteristics of and important lessons from the coronavirus disease 2019 (COVID-19) outbreak in China: Summary of a report of 72314 cases from the Chinese Center for Disease Control and Prevention. JAMA 2020;323:1239-42.
35Young BE, Ong SWX, Kalimuddin S, Low JG, Tan SY, Loh J, et al. Epidemiologic features and clinical course of patients infected with SARS-CoV-2 in Singapore. JAMA 2020. doi: 10.1001/jama.2020.3204.
36Chen N, Zhou M, Dong X, Qu J, Gong F, Han Y, et al. Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: A descriptive study. Lancet 2020;395:507-13.
37Guan WJ, Ni ZY, Hu Y, Liang WH, Ou CQ, He JX, et al. Clinical Characteristics of coronavirus disease 2019 in China. N Engl J Med 2020;382:1708-20.
38Huang C, Wang Y, Li X, Ren L, Zhao J, Hu Y, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet 2020;395:497-506.
39Zhao X, Liu B, Yu Y, Wang X, Du Y, Gu J, et al. The characteristics and clinical value of chest CT images of novel coronavirus pneumonia. Clin Radiol 2020;75:335-40.
40Yang X, Yu Y, Xu J, Shu H, Xia J, Liu H, et al. Clinical course and outcomes of critically ill patients with SARS-CoV-2 pneumonia in Wuhan, China: A single-centered, retrospective, observational study. Lancet Respir Med 2020. pii: S2213-2600 (20) 30079-5.
41Zhou F, Yu T, Du R, Fan G, Liu Y, Liu Z, et al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: A retrospective cohort study. Lancet 2020;395:1054-62.
42CDC COVID-19 Response Team. Severe outcomes among patients with coronavirus disease 2019 (COVID-19) — United States, February 12–March 16, 2020. MMWR Morb Mortal Wkly Rep 2020;69:343-6.
43Chen X, Zhao B, Qu Y, Chen Y, Xiong J, Feng Y, et al. Detectable serum SARS-CoV-2 viral load (RNAaemia) is closely correlated with drastically elevated interleukin 6 (IL-6) level in critically ill COVID-19 patients. Clin Infect Dis 2020. pii: ciaa449.
44Tian S, Hu W, Niu L, Liu H, Xu H, Xiao SY. Pulmonary pathology of early-phase 2019 novel coronavirus (COVID-19) pneumonia in two patients with lung cancer. J Thorac Oncol 2020. pii: S1556-0864 (20) 30132-5.
45Xu Z, Shi L, Wang Y, Zhang J, Huang L, Zhang C, et al. Pathological findings of COVID-19 associated with acute respiratory distress syndrome. Lancet Resp Med 2020;8:420-2.
46Mehta P, McAuley DF, Brown M, Sanchez E, Tattersall RS, Manson JJ. COVID-19: Consider cytokine storm syndromes and immunosuppression. Lancet 2020;395:1033-4.
47Monteleone G, Sarzi-Puttini PC, Ardizzone S. Preventing COVID-19-induced pneumonia with anticytokine therapy. Lancet Rheumatol 2020;2:e255-e256.
48Dong Y, Mo X, Hu Y, Qi X, Jiang F, Jiang Z, et al. Epidemiological characteristics of 2143 pediatric patients with 2019 coronavirus disease in China. Pediatrics 2020;pii: e20200702. doi: 10.1542/peds.2020-0702.
49Lu X, Zhang L, Du H, Zhang J, Li YY, Qu J, et al. SARS-CoV-2 infection in children. N Engl J Med 2020;382:1663-5.
50Onder G, Rezza G, Brusaferro S. Case-fatality rate and characteristics of patients dying in relation to COVID-19 in Italy. JAMA 2020. doi:10.1001/jama.2020.4683.
51Lighter J, Phillips M, Hochman S, Sterling S, Johnson D, Francois F, et al. Obesity in patients younger than 60 years is a risk factor for Covid-19 hospital admission. Clin Infect Dis 2020. pii: ciaa415.
52Sutton D, Fuchs K, D'Alton M, Goffman D. Universal screening for SARS-CoV-2 in women admitted for delivery. N Engl J Med 2020. doi: 10.1056/NEJMc2009316.
53Chen H, Guo J, Wang C, Luo F, Yu X, Zhang W, 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;395:809-15.
54Chen L, Li Q, Zheng D, Jiang H, Wei Y, Zou L, et al. Clinical characteristics of pregnant women with Covid-19 in Wuhan, China. N Engl J Med 2020. doi: 10.1056/NEJMc2009226.
55Zhu H, Wang L, Fang C, Peng S, Zhang L, Chang G, et al. Clinical analysis of 10 neonates born to mothers with 2019-nCoV pneumonia. Transl Pediatr 2020;9:51-60.
56Dong L, Tian J, He S, Zhu C, Wang J, Liu C, et al. Possible vertical transmission of SARS-CoV-2 from an infected mother to her newborn. JAMA 2020. doi:10.1001/jama.2020.4621.
57Zeng H, Xu C, Fan J, Tang Y, Deng Q, Zhang W, et al. Antibodies in infants born to mothers with COVID-19 pneumonia. JAMA 2020. doi: 10.1001/jama.2020.4861.
58Zeng L, Xia S, Yuan W, Yan K, Xiao F, Shao J, et al. Neonatal early-onset infection with SARS-CoV-2 in 33 neonates born to mothers with COVID-19 in Wuhan, China. JAMA Pediatr 2020. doi: 10.1001/jamapediatrics.2020.0878.
59World Health Organization. Laboratory Testing for Coronavirus Disease 2019 (COVID-19) in Suspected Human Cases: Interim Guidance, 2 March 2020. Geneva, Switzerland: World Health Organization; 2020. Available from: [Last accessed on 2020 May 09].
60Wang W, Xu Y, Gao R, Lu R, Han K, Wu G, et al. Detection of SARS-CoV-2 in different types of clinical specimens. JAMA 2020. doi:10.1001/jama.2020.3786.
61To KK, Tsang OT, Chik-Yan Yip C, Chan KH, Wu TC, Chan JM, et al. Consistent detection of 2019 novel coronavirus in saliva. Clin Infect Dis 2020;pii: ciaa149. doi: 10.1093/cid/ciaa149.
62To KK, Tsang OT, Leung WS, Tam AR, Wu TC, Lung DC, et al. Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: An observational cohort study. Lancet Infect Dis 2020;20:565-74.
63Zou L, Ruan F, Huang M, Liang L, Huang H, Hong Z, et al. SARS-CoV-2 viral load in upper respiratory specimens of infected patients. N Engl J Med 2020;382:1177-9.
64Wölfel R, Corman VM, Guggemos W, Seilmaier M, Zange S, Müller MA, et al. Virological assessment of hospitalized patients with COVID-2019. Nature 2020. doi: 10.1038/s41586-020-2196-x.
65Kimball A, Hatfield KM, Arons M, James A, Taylor J, Spicer K, et al. Asymptomatic and presymptomatic SARS-CoV-2 Infections in residents of a long-term care skilled nursing facility – King County, Washington, March 2020. MMWR Morb Mortal Wkly Rep 2020;69:377-81.
66Song JY, Yun JG, Noh JY, Cheong HJ, Kim WJ. Covid-19 in South Korea-Challenges of subclinical manifestations. N Engl J Med 2020;382:1858-9.
67Liu Y, Yan LM, Wan L, Xiang TX, Le A, Liu JM, et al. Viral dynamics in mild and severe cases of COVID-19. Lancet Infect Dis 2020;pii: S1473-3099(20)30232-2. doi: 10.1016/S1473-3099(20)30232-2.
68European Centre for Disease Prevention and Control. Discharge Criteria for Confirmed COVID-19 Cases – When is it safe to Discharge COVID-19 Cases from the Hospital or end Home Isolation?: European Centre for Disease Prevention and Control; 2020. Available from: [Last accessed on 2020 May 09].
69Guo L, Ren L, Yang S, Xiao M, Chang, Yang F, et al. Profiling early humoral response to diagnose novel coronavirus disease (COVID-19). Clin Infect Dis 2020;pii:ciaa310. doi: 10.1093/cid/ciaa310.
70US Food and Drug Administration. Coronavirus (COVID-19) Update: Serological Test Validation and Education Efforts: US Food and Drug Administration; 2020. Available from: [Last accessed on 2020 May 09].
71Australian National COVID-19 Clinical Evidence Taskforce. Australian Guidelines for the Clinical Care of People with COVID-19 2020; Published 04 March 2020. Available from: blished_guideline_4158-1_0.pdf. [Last accessed on 2020 May 09].
72National Institutes of Health. COVID-19 Treatment Guidelines Bethesda, Maryland: National Institutes of Health; 2020. Available from: [Last accessed on 2020 May 09].
73Wilson KC, Chotirmall SH, Bai C, Rello J; Behalf of the International Task Force on COVID-19. COVID-19: Interim Guidance on Management Pending Empirical Evidence. From an American Thoracic Society-led International Task Force: American Thoracic Society; 2020. Available from: nals/clinical-resources/disease-related-resources/covid-19-guidance.pdf. [Last accessed on 2020 May 09].
74World Health Organization. Clinical Management of Severe Acute Respiratory Infection when COVID-19 is Suspected. Geneva: World Health Organization; 2020. Available from: [Last accessed on 2020 May 09].
75Centers for Communicable Disease Control and Prevention. Information for Clinicians on Therapeutic Options for COVID-19 Patients: Centers for Communicable Disease Control and Prevention; 2020. Available from: erapeutic-options.html. [Last accessed on 2020 May 09].
76McCreary EK, Pogue JM. Coronavirus disease 2019 treatment: A review of early and emerging options. Open Forum Infect Dis 2020;7:ofaa105.
77Wang M, Cao R, Zhang L, Yang X, Liu J, Xu M, et al. Remdesivir and chloroquine effectively inhibit the recently emerged novel coronavirus (2019-nCoV) in vitro. Cell Res 2020;30:269-71.
78Grein J, Ohmagari N, Shin D, Diaz G, Asperges E, Castagna A, et al. compassionate use of remdesivir for patients with severe Covid-19. N Engl J Med 2020. doi: 10.1056/NEJMoa2007016.
79Lescure FX, Bouadma L, Nguyen D, Parisey M, Wicky PH, Behillil S, et al. Clinical and virological data of the first cases of COVID-19 in Europe: A case series. Lancet Infect Dis 2020;pii: S1473-3099(20)30200-0. doi: 10.1016/S1473-3099(20)30200-0.
80Lythgoe MP, Middleton P. Ongoing clinical trials for the management of the COVID-19 pandemic. Trends Pharmacol Sci 2020. pii: S0165-6147(20)30070-5.
81Omrani AS, Memish ZA. Therapeutic options for Middle East respiratory syndrome coronavirus (MERS-CoV) infection: How close are we? Curr Treat Options Infect Dis 2015;7:202-16.
82Cao B, Wang Y, Wen D, Liu W, Wang J, Fan G, et al. A trial of lopinavir-ritonavir in adults hospitalized with severe Covid-19. N Engl J Med 2020;382:1787-99.
83Hoffmann M, Schroeder S, Kleine-Weber H, Müller MA, Drosten C, Pöhlmann S. Nafamostat mesylate blocks activation of SARS-CoV-2: New treatment option for COVID-19. Antimicrob Agents Chemother 2020. pii: AAC.00754-20. doi: 10.1128/AAC.00754-20.
84Alhazzani W, Moller MH, Arabi YM, Loeb M, Gong MN, Fan E, et al. Surviving sepsis campaign: Guidelines on the management of critically ill adults with Coronavirus Disease 2019 (COVID-19). Intensive Care Med 2020. doi: 10.1007/s00134-020-06022-5.
85US Food and Drug Administration. Recommendations for Investigational COVID-19 Convalescent Plasma; 2020. Available from: id-19-convalescent-plasma. [Last accessed on 2020 May 09].
86Roback JD, Guarner J. Convalescent plasma to treat COVID-19: Possibilities and challenges. JAMA 2020;323:1561-2.
87Duan K, Liu B, Li C, Zhang H, Yu T, Qu J, et al. Effectiveness of convalescent plasma therapy in severe COVID-19 patients. Proc Natl Acad Sci U S A 2020;117:9490-6.
88Shen C, Wang Z, Zhao F, Yang Y, Li J, Yuan J, et al. Treatment of 5 critically ill patients with COVID-19 with convalescent plasma. JAMA 2020;323:1582-9.
89Jia Z, Lu Z. Modelling COVID-19 transmission: From data to intervention. Lancet Infect Dis 2020;pii: S1473-3099(20)30258-9. doi: 10.1016/S1473-3099(20)30258-9.
90Koo JR, Cook AR, Park M, Sun Y, Sun H, Lim JT, et al. Interventions to mitigate early spread of SARS-CoV-2 in Singapore: A modelling study. Lancet Infect Dis 2020;pii: S1473-3099(20)30162-6. doi: 10.1016/S1473-3099(20)30162-6.
91Gudbjartsson DF, Helgason A, Jonsson H, Magnusson OT, Melsted P, Norddahl GL, et al. Spread of SARS-CoV-2 in the Icelandic population. N Engl J Med 2020. doi: 10.1056/NEJMoa2006100.
92Xu S, Li Y. Beware of the second wave of COVID-19. Lancet 2020;395:1321-2.
93World Health Organization. DRAFT Landscape of COVID-19 Candidate Vaccines – 20 April 2020: World Health Organization; 2020. Available from: [Last accessed on 2020 May 09].
94Yamey G, Schäferhoff M, Hatchett R, Pate M, Zhao F, McDade KK. Ensuring global access to COVID-19 vaccines. Lancet 2020;395:1405-6.
95Lurie N, Saville M, Hatchett R, Halton J. Developing Covid-19 vaccines at pandemic speed. N Engl J Med 2020. doi: 10.1056/NEJMp2005630.