2019-nCOv (UpToDate, 2020-2-10)

Novel coronavirus (2019-nCoV)

Author:

Kenneth McIntosh, MD

Section Editor:

Martin S Hirsch, MD

Deputy Editor:

Allyson Bloom, MD

Contributor Disclosures

All topics are updated as new evidence becomes available and our peer review process is complete.

Literature review current through: Jan 2020. | This topic last updated: Feb 10, 2020.

INTRODUCTIONCoronaviruses are important human and animal pathogens. At the end of 2019, a novel coronavirus, currently designated 2019-nCoV, was identified as the cause of a cluster of pneumonia cases in Wuhan, a city in the Hubei Province of China. It rapidly spread, resulting in an epidemic throughout China, with sporadic cases reported globally.

Understanding of this novel coronavirus is evolving. Interim guidance has been issued by the World Health Organization and by the United States Centers for Disease Control and Prevention [1-3]. Links to these and other related society guidelines are found elsewhere. (See 'Society guideline links' below.)

This topic will discuss the epidemiology, clinical features, diagnosis, management, and prevention of 2019-CoV infection. Community-acquired coronaviruses, severe acute respiratory syndrome (SARS) coronavirus, and Middle East respiratory syndrome (MERS) coronavirus are discussed separately. (See "Coronaviruses" and "Severe acute respiratory syndrome (SARS)" and "Middle East respiratory syndrome coronavirus: Virology, pathogenesis, and epidemiology".)

EPIDEMIOLOGY

Geographic distribution — Since the first reports of cases from Wuhan, a city in the Hubei Province of China, at the end of 2019, more than 40,000 laboratory-confirmed cases in China have been reported, and the case count has been rising daily. The majority of reports are from Hubei and surrounding provinces, but numerous cases have been reported in other provinces and municipalities throughout China [4,5]. Sporadic but increasing cases have also been reported in other countries globally (including countries in Asia and Europe, as well as Australia, the United States [Washington state, Illinois, California, Arizona, Massachusetts, and Wisconsin], and Canada), mainly among travelers from China [6-10]. Updated case counts in English can be found on the World Health Organization and European Centre for Disease Prevention and Control websites.

Transmission — Understanding of the transmission risk is incomplete.

Epidemiologic investigation in Wuhan identified an initial association with a seafood market where most patients had worked or visited and which was subsequently closed for disinfection [11]. The seafood market also sold live rabbits, snakes, and other animals.

However, as the outbreak progressed, most laboratory-confirmed cases had no contact with this market, and cases were identified among health care workers and other contacts of patients with 2019-nCoV infection. Human-to-human transmission has been confirmed in China [12] and has also been identified in other countries [13], including the United States. The question of whether asymptomatic individuals infected with 2019-nCoV can transmit the virus to others remains controversial [14,15].

VIROLOGYFull-genome sequencing and phylogenic analysis indicated that 2019-nCoV is a betacoronavirus in the same subgenus as the severe acute respiratory syndrome (SARS) virus (as well as several bat coronaviruses), but in a different clade. The apparent structure of the receptor-binding gene region was very similar to that of the SARS coronavirus, and there is speculation that it will be shown to use the same receptor for cell entry. The Middle East respiratory syndrome (MERS) virus, another betacoronavirus, was more distantly related [16,17]. The closest RNA sequence similarity is to two bat coronaviruses, and it appears likely that bats are the primary source; whether 2019-nCoV is transmitted directly from bats or through some other mechanism (eg, through an intermediate host) is unknown [18]. (See "Coronaviruses", section on 'Viral serotypes'.)

CLINICAL FEATURES

Incubation period — The incubation period of 2019-nCoV is thought to be within 14 days following exposure.

In a family cluster of infections, the onset of fever and respiratory symptoms occurred approximately three to six days after presumptive exposure [19]. Similarly, in an analysis of 10 patients with confirmed 2019-nCoV-associated pneumonia, the estimated mean incubation period was five days [12].

Clinical presentation — Pneumonia appears to be the most frequent manifestation of infection, characterized primarily by fever, cough, dyspnea, and bilateral infiltrates on chest imaging [20,21]. However, patients can present with a spectrum of disease, ranging from mild respiratory illnesses, particularly in younger adults or children, to severe disease (including respiratory failure, septic shock, or other organ failure requiring intensive care) [19,22-24]. The frequency of asymptomatic or mild infection is unknown, but approximately 20 percent of confirmed patients have had critical illness. The overall case fatality rate is uncertain but appears to be less than 3 percent [25]. Most of the fatal cases have occurred in patients with underlying medical comorbidities.

In a study describing 41 of the initial cases of pneumonia identified in the outbreak, 73 percent of cases were males, and the median age was 49 years (interquartile range 41 to 58 years) [20]. Nearly all (98 percent) reported fever, 76 percent had cough, and 44 percent had myalgias/fatigue. Dyspnea developed in 55 percent after a median of eight days of illness, suggesting the possibility of clinical deterioration later in the course of illness. Lymphopenia was common, and all patients had parenchymal lung abnormalities on computed tomography of the chest, including ground glass opacities, subsegmental consolidation, and multilobular consolidation. Acute respiratory distress syndrome developed in 30 percent, and mechanical ventilation was implemented in 10 percent. Upper respiratory symptoms and diarrhea were both seen but in fewer than 10 percent. Similar clinical features were described in a cohort of 99 patients with confirmed 2019-nCoV infection admitted to an infectious disease specialty hospital in Wuhan [21].

EVALUATION AND DIAGNOSISThe approach to initial management should focus on early recognition of suspect cases, immediate isolation, and institution of infection control measures. At present, the possibility of 2019-nCoV should be considered in patients with fever and/or lower respiratory tract symptoms who reside in or have recently (within the prior 14 days) traveled to China or who have had recent (within the prior 14 days) close contact with a confirmed or suspected case of 2019-nCoV.

When 2019-nCoV is suspected, infection control measures should be implemented and public health officials notified. Infection control precautions are discussed elsewhere. (See 'Infection control for suspected or confirmed cases' below.)

The specific case definitions and clinical criteria for diagnostic evaluation differ slightly between expert groups. Suspect case definitions from the World Health Organization are found in its technical guidance online; clinical criteria for patients under investigation from the United States Centers for Disease Control and Prevention (CDC) are detailed in the table (table 1).

For patients who meet their criteria, in addition to testing for other respiratory pathogens, the CDC recommends collection of specimens for 2019-nCoV testing from the upper respiratory tract (nasopharyngeal and oropharyngeal swab) and, if possible, the lower respiratory tract (sputum, tracheal aspirate, or bronchoalveolar lavage). Induction of sputum is not indicated. Additional specimens (eg, stool, urine) can also be collected. 2019-nCoV is detected by polymerase chain reaction; in the United States, testing is performed by the CDC or a CDC-qualified lab [3].

For safety reasons, specimens from a patient with suspected or documented 2019-nCoV should not be submitted for viral culture.

MANAGEMENT

Hospital care — Management of patients with suspected or documented 2019-nCoV infections consists of ensuring appropriate infection control, as below (see 'Infection control for suspected or confirmed cases' below), and supportive care. Clinical guidance can be found on the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) websites [26,27].

Supportive care for sepsis and acute respiratory distress syndrome is discussed elsewhere. (See "Evaluation and management of suspected sepsis and septic shock in adults" and "Acute respiratory distress syndrome: Supportive care and oxygenation in adults".)

The WHO and CDC generally recommend glucocorticoids not be used in 2019-nCoV pneumonia unless there are other indications (such as exacerbation of chronic obstructive pulmonary disease) [26,27]. Glucocorticoids have been associated with an increased risk for mortality in patients with influenza and delayed viral clearance in patients with Middle East respiratory syndrome coronavirus (MERS-CoV) infection. Although they were widely used in management of severe acute respiratory syndrome (SARS), there was no good evidence for benefit, and there was persuasive evidence of adverse short- and long-term harms [28]. (See "Treatment of seasonal influenza in adults", section on 'Adjunctive therapies' and "Middle East respiratory syndrome coronavirus: Treatment and prevention", section on 'Treatment'.)

Investigational agents are being explored for antiviral treatment of 2019-nCoV infections. As an example, the manufacturer of remdesivir, a novel nucleotide analogue that has activity against related coronaviruses (including SARS and MERS-CoV) in vitro and in animal studies [29], is planning randomized clinical trials in China to evaluate the efficacy and safety of remdesivir against 2019-nCoV [30]. The compassionate use of remdesivir through an investigational new drug application was described in a case report of one of the first patients with 2019-nCoV infection in the United States [31]. Any clinical impact of remdesivir on 2019-nCoV remains unknown.

Home care — Home management may be appropriate for patients with mild infection who can be adequately isolated in the outpatient setting [26,27]. Management of such patients should focus on prevention of transmission to others, and monitoring for clinical deterioration, which should prompt hospitalization.

Interim recommendations on home management of patients with 2019-nCoV infections can be found on the WHO and CDC websites [32-34].

PREVENTION

Infection control for suspected or confirmed cases — Infection control to limit transmission is an essential component of care of patients with suspected or documented 2019-nCoV infection.

Individuals with suspected infection in the community should be advised to wear a medical mask to contain their respiratory secretions and seek medical attention. (See 'Evaluation and diagnosis' above.)

In the health care setting, the World Health Organization (WHO) and United States Centers for Disease Control and Prevention (CDC) recommendations for infection control for suspected or confirmed infections differ slightly:

●The WHO recommends standard, contact, and droplet precautions, with eye or face protection [35]. The addition of airborne precautions is warranted during aerosol-generating procedures, such as tracheal intubation, non-invasive ventilation, tracheotomy, cardiopulmonary resuscitation, manual ventilation before intubation, and bronchoscopy.

●The CDC recommends standard, contact, and airborne precautions, with eye protection [36]. If an airborne infection isolation room (ie, a single patient negative pressure room) is not readily available, the patient should wear a mask and be placed in a private room with the door closed, and any personnel entering the room should wear the appropriate personal protection equipment. Patients with suspected or confirmed 2019-nCoV infection who require hospitalization should be cared for in a facility that can provide an airborne infection isolation room.

Elements of the different types of infection control precautions are detailed in the table (table 2).

Preventing exposure — The WHO advises general measures to reduce transmission of infection, including diligent hand washing, respiratory hygiene, and avoiding close contact with live or dead animals and ill individuals.

It notes that for people without respiratory symptoms, wearing a medical mask in the community is not required, even if 2019-nCoV is prevalent in the area; wearing a mask does not decrease the importance of other general measures to prevent infection, and it may result in unnecessary cost and supply problems [37].

Individuals who are caring for patients with suspected or documented 2019-nCoV at home, however, should wear a tightly fitting medical mask when in the same room as that patient.

Global public health measures — On January 30, 2020, the WHO declared the 2019-nCoV outbreak a public health emergency of international concern.

The WHO does not recommend international travel restrictions but does acknowledge that movement restriction may be temporarily useful in some settings. The WHO advises exit screening for international travelers from areas with ongoing transmission of 2019-nCoV to identify individuals with fever, cough, or potential high-risk exposure [38].

In China, health officials announced a restriction of public transportation within and a halt of air and rail traffic out of Wuhan and other surrounding areas [4]. In the United States, the CDC recommends that individuals avoid all nonessential travel to China [39]; United States citizens returning from the Hubei Province are undergoing a 14-day quarantine, while those returning from other parts of China are undergoing screening for signs of illness on arrival (with subsequent self-monitoring) as long as there is no known high-risk exposure; foreign nationals who have been in China in the prior 14 days are temporarily suspended from entry. Additional guidance regarding risk assessment and management of persons with a suspected exposure to 2019-nCoV can be found on the CDC website [40].

SPECIAL POPULATIONS

Pregnant women — Minimal information is available regarding 2019-nCoV infection during pregnancy. One case of mother-to-child transmission has been reported [41]. The approach to prevention, evaluation, diagnosis, and treatment of pregnant women with suspected 2019-nCoV infection should be similar to that in nonpregnant individuals (as described above), with consideration that pregnant women with other potentially severe respiratory infections, such as influenza, severe acute respiratory syndrome (SARS)-CoV, or Middle East respiratory syndrome (MERS)-CoV, appear to be more vulnerable to developing severe sequelae.

SOCIETY GUIDELINE LINKSLinks to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Novel coronavirus".)

INFORMATION FOR PATIENTSUpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topic (see "Patient education: 2019 novel coronavirus (The Basics)")

SUMMARY AND RECOMMENDATIONS

●In late 2019, a novel coronavirus, designated 2019-nCoV, was identified as the cause of an outbreak of acute respiratory illness. It has subsequently spread to include more than 40,000 cases in China and scattered but increasing cases worldwide, prompting the World Health Organization (WHO) to declare a public health emergency in late January 2020. (See 'Epidemiology' above.)

●The possibility of 2019-nCoV should be considered in patients with fever and/or lower respiratory tract symptoms who reside in or have recently (within the prior 14 days) traveled to China or who have had recent (within the prior 14 days) close contact with a confirmed or suspected case of 2019-nCoV (table 1). (See 'Clinical features' above and 'Evaluation and diagnosis' above.)

●Upon suspicion, infection control measures should be implemented and public health officials notified. In health care settings in the United States, the Centers for Disease Control and Prevention (CDC) recommends standard, contact, and airborne precautions (table 2), as well as eye protection. (See 'Infection control for suspected or confirmed cases' above.)

●In addition to testing for other respiratory pathogens, upper and lower respiratory tract specimens should be collected for 2019-nCoV testing. Additional specimens (eg, stool, urine) can also be collected. (See 'Evaluation and diagnosis' above.)

●Management consists of supportive care. Home management may be possible for patients with mild illness who can be adequately isolated in the outpatient setting. (See 'Management' above.)

●The WHO has issued interim guidance on surveillance case definitions, laboratory diagnosis, and clinical management. The CDC has also issued interim guidance. (See 'Society guideline links' above.)

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REFERENCES

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