Widespread outbreaks of novel (new) coronavirus infection have occurred in each of the past two decades, and the current outbreak poses the third threat of a severe novel coronavirus epidemic on a global scale. In response to a 13-fold increase in the number of reported cases within the span of two weeks and active cases in more than 100 countries, the WHO reached a decision that the COVID-19 outbreak should be characterized as a pandemic.

Education Category: Infection Control / Internal Medicine
Release Date: 02/01/2020
Expiration Date: 01/31/2023


This outbreak is ongoing. As the situation evolves, the course is being revised to reflect new information. The last update was done March 27, 2020.


This course is designed for dental professionals who may identify or educate patients regarding coronavirus infection.

Accreditations & Approvals

NetCE Nationally Approved PACE Program Provider for FAGD/MAGD credit. Approval does not imply acceptance by any regulatory authority or AGD endorsement. 10/1/2015 to 9/30/2021 Provider ID #217994. NetCE is an ADA CERP Recognized Provider. ADA CERP is a service of the American Dental Association to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP does not approve or endorse individual courses or instructors, nor does it imply acceptance of credit hours by boards of dentistry. Concerns or complaints about a CE provider may be directed to the provider or to ADA CERP at www.ada.org/cerp. NetCE is approved as a provider of continuing education by the Florida Board of Dentistry, Provider #50-2405. NetCE is a Registered Provider with the Dental Board of California. Provider Number RP3841. Completion of this course does not constitute authorization for the attendee to perform any services that he or she is not legally authorized to perform based on his or her license or permit type.

Designations of Credit

NetCE designates this activity for 2 continuing education credits. AGD Subject Code 148. This course meets the Dental Board of California's requirements for 2 unit(s) of continuing education. Dental Board of California course #02-3841-20295.

Course Objective

The purpose of this course is to provide dental professionals an overview of the 2019–2020 global outbreak of novel human coronavirus (SARS-CoV-2) infection, including background epidemiology, clinical features, mode of transmission, epidemic potential, and the clinical and public health measures recommended to limit the spread of infection and control the outbreak.

Learning Objectives

Upon completion of this course, you should be able to:

  1. Differentiate between the common, ubiquitous strains of human coronavirus and novel (outbreak) strains with respect to epidemiology, modes of transmission, spectrum of illness, and public health implications.
  2. Characterize the clinical and public health experience gained from the two prior novel human coronavirus epidemics, SARS and MERS, and how that informs our understanding and response to the current outbreak.
  3. Provide current health precautions and travel advice to the elderly and to persons returning from or needing to travel to countries with heavy COVID-19 disease activity.
  4. Access and implement guideline recommendations for clinical assessment, diagnostic testing, appropriate isolation precautions, and monitoring of a patient with recent exposure to, suspected infection with, or newly diagnosed COVID-19.


John M. Leonard, MD, Professor of Medicine Emeritus, Vanderbilt University School of Medicine, completed his post-graduate clinical training at the Yale and Vanderbilt University Medical Centers before joining the Vanderbilt faculty in 1974. He is a clinician-educator and for many years served as director of residency training and student educational programs for the Vanderbilt University Department of Medicine. Over a career span of 40 years, Dr. Leonard conducted an active practice of general internal medicine and an inpatient consulting practice of infectious diseases.

Faculty Disclosure

Contributing faculty, John M. Leonard, MD, has disclosed no relevant financial relationship with any product manufacturer or service provider mentioned.

Division Planner

William E. Frey, DDS, MS, FICD

Division Planner Disclosure

The division planner has disclosed no relevant financial relationship with any product manufacturer or service provider mentioned.

About the Sponsor

The purpose of NetCE is to provide challenging curricula to assist healthcare professionals to raise their levels of expertise while fulfilling their continuing education requirements, thereby improving the quality of healthcare.

Our contributing faculty members have taken care to ensure that the information and recommendations are accurate and compatible with the standards generally accepted at the time of publication. The publisher disclaims any liability, loss or damage incurred as a consequence, directly or indirectly, of the use and application of any of the contents. Participants are cautioned about the potential risk of using limited knowledge when integrating new techniques into practice.

Disclosure Statement

It is the policy of NetCE not to accept commercial support. Furthermore, commercial interests are prohibited from distributing or providing access to this activity to learners.

Table of Contents

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#54150: The Coronavirus Disease (COVID-19) Pandemic

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Coronaviruses (a subfamily of Coronaviridae) are enveloped, single-stranded RNA viruses that are broadly distributed among humans, other mammals, and birds. Under electron microscopy, the outer envelope of the virion shows club-like surface projections that confer a crown-like appearance to the virus, which accounts for the name given to this family of viruses. The nucleocapsid is a long, folded strand that tends to spontaneous mutations and frequent recombination of the genome, which may account, in part, for changes in transmissibility and pathogenicity that permit a new (novel) form of coronavirus infection in humans.

In addition to four specific subtypes of coronavirus commonly found in humans, other strains have been detected in many different species of animals, including bats, cats, camels, and cattle. On rare occasions, an animal coronavirus is responsible for zoonotic infection in humans, meaning that a novel coronavirus is transmitted from an animal host to one or more humans, producing clinical illness that may result in secondary spread among persons in close contact. The wide distribution, genetic diversity, and frequent shifts in the genome, combined with unique human-animal interface activities, are considered important factors in the periodic emergence of new coronavirus outbreaks in human populations [1,2].


Common Strains

Human coronavirus (HCoV) was first identified in 1965, isolated from a patient with what was described as the common cold [3]. Subsequently, four types of HCoV have been detected commonly in respiratory secretions of children and adults in scattered regions of the globe, labeled HCoV-229E, -NL63, -OC43, and -HKU1. These agents are a common cause of mild-to-moderate upper respiratory illness, such as the common cold, bronchitis, bronchiolitis in infants and children, and asthma exacerbation. On occasion, as with influenza, HCoVs can cause serious lower respiratory tract infection (viral pneumonia), a complication more common to persons with underlying cardiopulmonary disease or weakened immune systems.

Novel Coronavirus Outbreaks

In addition to the seasonal infections caused by the ambient, adaptive HCoVs described, widespread outbreaks of novel (new) coronavirus infection have occurred in each of the past two decades, and the 2019–2020 Wuhan, China, outbreak poses the third threat of a severe novel coronavirus epidemic on a global scale [1,4]. The common epidemiologic feature of these outbreaks is an initial point source cluster of zoonotic infection followed by secondary spread of the virus via human-to-human transmission. Among the factors thought to be conducive to the emergence of such outbreaks are the following: genomic recombination in an animal CoV capsid that renders the virus better adapted to human infection (and perhaps more virulent); and dietary practices and cultural determinants that bring humans into close contact with livestock or raw meat and carcasses of wild animals and birds, thereby facilitating transmission from an infected animal host to humans. After infection is established, secondary viral transmission occurs through close person-to-person contact by way of droplet nuclei propelled into the air during coughing and sneezing. The first two known novel coronavirus outbreaks, severe acute respiratory syndrome coronavirus (SARS-CoV) in 2003 and the Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012, are considered to be zoonotic in origin and were associated with serious, sometimes fatal illness.

Severe Acute Respiratory Syndrome (SARS-CoV)

Infection with SARS-CoV was first recognized in China in November 2002, and signs of an outbreak in Asia were evident by February 2003 [3]. Epidemiologic investigation found that early cases of SARS-CoV represented zoonotic infection involving transmission from civet cats to humans. Over the next several months, SARS-CoV spread to countries in North America, South America, Europe, and other parts of Asia before the global outbreak was contained later in the same year.

SARS-CoV infection began with fever, headache, malaise, and arthralgia/myalgia followed in two to seven days by cough, shortness of breath, and in most patients, signs of pneumonia [3].

According to the World Health Organization (WHO), the 2002–2003 outbreak caused 8,098 probable cases of SARS worldwide and 774 deaths. Just eight cases were identified in the United States. Since 2004, there have been no additional known cases of SARS-CoV infection reported anywhere in the world [3].

In response to the 2003 global SARS outbreak, the Centers for Disease Control and Prevention (CDC), working in concert with the WHO, developed a strategy for controlling the epidemic that included the following elements [3]:

  • Activated the Emergency Operations Center to provide around-the-clock coordination and response.

  • Committed more than 800 medical experts and support staff to work on the SARS response and to assist with ongoing investigations around the world.

  • Provided assistance to state and local health departments in investigating possible cases of SARS in the United States.

  • Conducted extensive laboratory testing of clinical specimens from patients with SARS to identify the cause of the disease.

  • Initiated a system for distributing health alert notices to travelers who may have been exposed to cases of SARS.

This experience provided a blueprint for responding to the 2019–2020 coronavirus outbreak in China.

Middle East Respiratory Syndrome (MERS-CoV)

MERS-CoV was first reported in Saudi Arabia in 2012, and all cases to date have been linked to countries in or near the Arabian Peninsula. Travel-associated MERS-CoV infection has been reported from many countries around the world, including two imported cases diagnosed in the United States in 2014 involving unlinked healthcare providers who had recently lived and worked in Saudi Arabia. There is epidemiologic evidence for two modes of transmission: zoonotic infection from an animal reservoir to humans (with camels acting as the intermediate host), and person-to-person transmission via close contact with an index case, as described in association with a family case cluster and a nosocomial outbreak [5,6,7].

Most persons with confirmed MERS-CoV infection have had moderately severe respiratory illness manifest by fever, cough, and shortness of breath, often complicated by pneumonia and respiratory failure. The case-fatality rate approaches 40%. Most deaths have been in patients with pre-existing chronic conditions such as diabetes, cancer, or heart, lung, or renal disease. Sporadic cases of MERS-CoV continue to appear in various parts of the Middle East [3].


In December 2019, Chinese physicians in Hubei Province, China, began an investigation of a cluster of cases of severe viral pneumonia in area hospitals linked to exposure to a large seafood and live animal wholesale market in Wuhan City. In the weeks following, it became evident that a large outbreak of respiratory illness was rapidly emerging within Wuhan City and nearby communities, reaching the thousands by mid-January.

On January 24, Chinese scientists reported the results of viral diagnostic studies conducted on bronchoalveolar lavage specimens obtained from three Wuhan City patients hospitalized in December with severe bilateral interstitial, alveolar pneumonia [2]. The investigation identified a viral genome matched to lineage B of the genus betacoronavirus, showing more than 85% match with a SARS-like CoV genome previously described in bats. Ultrathin sections of infected human airway epithelial cells showed inclusion bodies filled with virus particles in membrane-bound vesicles in the cytoplasm. On electron microscopy, the observed morphology of the virion is consistent with the Coronaviridae family.

This newly identified coronavirus is now known to be the etiologic agent responsible for the Wuhan, China, outbreak and is named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The resultant disease is referred to as COVID-19. Like SARS-CoV and MERS-CoV, SARS-CoV-2 is a betacoronavirus that likely has its origin in bats, with one or more animals serving as the intermediate host for zoonotic infection in humans. According to CDC reports, virus sequences from imported cases in this country are similar to the one initially posted by China, suggesting a likely single, recent emergence of this virus from an animal reservoir [12].

The rapid accumulation of many new cases in Wuhan City during the months of December 2019 and January and February 2020, combined with evidence of spread to persons from other nearby provinces in central China and reports of acute infection in healthcare workers, point to facile human-to-human transmission of SARS-CoV-2 as the key factor responsible for continued propagation of the outbreak.


As of March 2020, there is limited data upon which to draw definitive conclusions about the full clinical features of the disease. Extrapolating from limited epidemiologic information and what is known from previous novel coronavirus outbreaks (SARS and MERS), the incubation period of SARS-CoV-2 is estimated to be 5 to 7 days on average, with a range of 2 to 14 days. The spectrum of illness appears to range from mild upper respiratory infection to fever, cough, and shortness of breath, with substantial risk of developing bilateral pneumonia complicated by respiratory failure and death. Based on official case reports through the month of January 2020, the mortality rate for confirmed cases of COVID-19 reported from China is approximately 3%.

The first report describing the clinical features of hospitalized patients with COVID-19-related pneumonia in Wuhan City was published online January 24, 2020 [9]. As of January 2, 41 admitted patients had been identified as having laboratory-confirmed 2019-nCoV infection; 30 (73%) were men and 27 (66%) had been exposed to the open-air Huanan Seafood Market. The median age was 49 years, and fewer than half of the patients had a history of underlying chronic disease. Common symptoms at onset of illness were fever (98%), cough (76%), and myalgia or fatigue (44%). Dyspnea developed in 22 patients (55%), with a median time from illness onset to dyspnea of eight days. Common laboratory abnormalities included leukopenia, lymphopenia, and mild hepatic enzyme elevations. All 41 patients were reported to have pneumonia, and all save one had radiographic evidence of bilateral involvement. The typical findings on chest computed tomography (CT) images of intensive care unit (ICU) patients were bilateral multilobar and segmental areas of consolidation. Acute respiratory distress syndrome developed in 12 (32%) patients, 13 (32%) were admitted to an ICU, and 6 died (15%).

A larger retrospective study examined the clinical characteristics of COVID-19 in a cohort of 1,099 hospitalized patients in China during the first two months of the outbreak [17]. The most common symptoms were fever (43.8% on admission, 88.7% during hospitalization), cough (67.8%), and fatigue (38.1%) [17]. The most common patterns on chest CT were ground-glass opacification (36.4%) and bilateral patchy shadowing (51.8%). Some degree of radiographic or CT abnormality was evident in 82% of patients with nonsevere disease and 97% of patients with severe disease. Lymphocytopenia was present in 83.2% of the patients on admission. Sixty-seven patients (6.1%) were admitted or transferred to the ICU, 2.3% required mechanical ventilation, and 1.4% died [17].

Risk factors for severe disease are only partially understood, as there are no community-based surveillance data upon which to accurately determine the true incidence of infection and age-related case-fatality rates. Among more than 44,000 confirmed case of COVID-19 in China as of February 11, 2020, 77.8% were persons 30 to 69 years of age and 19% were severely or critically ill [15,18]. The proportion of case fatalities among patients 60 to 69 years of age was 3.6%; among those 70 to 79 years of age, the rate was 8%, and among those 80 years of age and older, the rate was 14.8%. Case fatality for patients with comorbidities ranged from 6% (chronic lung disease) to 10.5% (cardiovascular disease). Patients who reported no underlying medical conditions had an overall case fatality of 0.9%. Only 2.1% of cases were in persons younger than 20 years of age, and no deaths were reported in those younger than 10 years of age.


A real-time reverse transcription-polymerase chain reaction (rRT-PCR) test, based on genomic sequencing of the virus in China and at the CDC, can be used to diagnose SARS-CoV-2 in respiratory and serum samples from clinical specimens. On January 24, 2020, the CDC publicly posted the assay protocol for this test. As of March 16, 2020, testing for this virus in the United States can be done at state and local public health laboratories in all states and at the CDC [16]. Information on specimen collection, handling, and storage is available online at https://www.cdc.gov/coronavirus/2019-nCoV/lab/guidelines-clinical-specimens.html.


There is at present no vaccine and no established antiviral regimen available for prevention and treatment of SARS-CoV-2 infections; care is supportive and, for the purposes of limiting spread, should be carried out in a controlled environment under Isolation Precautions.

According to a National Institutes of Health briefing reported by the Infectious Disease Society of America, research efforts are underway to develop better diagnostics, treatments, and vaccines [10]. As noted, the CDC has already developed a diagnostic test based on genetic sequencing of the virus shared by Chinese investigators. Two antiviral agents—remdesivir, a drug tried unsuccessfully in the Ebola outbreak, and lopinavir/ritonavir (Kaletra), a combination antiviral used for treatment of human immunodeficiency virus (HIV)—are being offered on a compassionate use basis in China. However, one study of hospitalized patients with COVID-19 in China found no difference in time to clinical improvement and no difference in eventual outcome with lopinavir/ritonavir treatment [20].

In anticipation of a possible "worst-case scenario" wherein the SARS-CoV-2 outbreak becomes a persisting or recurring epidemic, an effort is already underway to develop a coronavirus vaccine utilizing the genetic sequencing shared by China [10]. A preliminary trial to assess safety is planned in the first quarter of 2020, followed by trials to determine vaccine effectiveness, which would require additional months for completion.

Investigational Therapeutics

Remdesivir is an investigational antiviral drug reported to have in-vitro activity against SARS-CoV-2 [15]. Some patients with COVID-19 have received intravenous remdesivir for compassionate use outside of a clinical trial setting. In China, multiple clinical trials of investigational therapeutics have been implemented, including two clinical trials of remdesivir. An NIH adaptive randomized controlled clinical trial of investigational therapeutics for hospitalized patients with COVID-19 in the United States was approved by the U.S. Food and Drug Administration (FDA); the first investigational therapeutic to be studied is remdesivir.

In vitro studies show that chloroquine and hydroxychloroquine (commonly used to treat malaria) interfere with the replication cycle of coronaviruses, including SARS-CoV-2 and thus may offer some therapeutic efficacy for treatment of severe COVID-19 [21]. Clinical trials are underway in China and the United States. Based on early observations of possible efficacy, clinicians may consider administering hydroxychloroquine to patients with COVID-19 so ill as to require hospitalization and having risk factors for severe disease (i.e., age older than 60 years, underlying medical conditions, and/or signs of viral pneumonia). The suggested dosage regimen is hydroxychloroquine administered orally in a loading dose of 400 mg twice daily (for one day) then 200 mg twice daily for four days [22]. One should bear in mind the possibility of adverse effects, including QT-prolongation and potential drug-drug interactions.



Beginning in January 2020, and in association with travel to and from China, cases of confirmed SARS-CoV-2 infection began to be reported from multiple countries around the world, including the United States. The WHO monitors developments and tracks the progress of the epidemic, providing daily Situation Reports at its website [8]. In an effort to curb the spread of infection, the WHO and national agencies have developed clinical criteria to guide the evaluation and management of persons with significant exposure and/or compatible illness.

In the initial weeks of the outbreak, cases reported in countries outside China were occurring primarily in returning travelers who had visited Wuhan City or nearby locales in central China. With time, the extent of person-to-person spread unrelated to travel has become increasingly clear; local transmission and community spread is now evident in many countries, and regional epidemics of COVID-19 are occurring in South Korea, Iran, Italy, and other parts of Europe. As of March 27, 2020, there were 509,164 confirmed cases globally [8]. There have been 82,078 cases and 3,298 deaths in China. Outside of China, there have been 427,086 confirmed cases and 20,037 deaths reported from more than 150 countries.

On January 30, 2020, the WHO declared the COVID-19 epidemic a Public Health Emergency of International Concern, thereby invoking the powers of the 2005 International Health Regulations (IHR). The IHR require all countries to develop a national preparedness program, conduct surveillance, exercise public health measures, and report any internationally significant event. This decision fosters a strong international collaborative effort and strengthens support for countries with limited health system resources. On March 11, 2020, in response to a 13-fold increase in the number of reported cases within the span of two weeks and active cases in 114 countries, the WHO reached a decision that the COVID-19 outbreak should be characterized as a pandemic.

In early February 2020, the CDC implemented a U.S. port of entry surveillance program at 20 major airports receiving returning travelers from China in order to identify those with a history of significant exposure or symptoms that merit additional health assessment. In mid-March 2020, entry of foreign nationals from China, Iran, most European countries, and the UK and Ireland was suspended, and the CDC recommended that travelers avoid all nonessential travel to these destinations as well as South Korea. In addition, the CDC recommends that older adults or those who have serious chronic medical conditions consider postponing travel to most global destinations [13].

WHO Advice to the Public

The WHO has posted standard recommendations for the general public (residing in or traveling to endemic regions) designed to reduce exposure to, and transmission of, a range of infectious illnesses [11]. In addition, WHO has issued advice for the two groups of people at high risk for severe illness from COVID-19: older persons, especially older than 60 years of age, and persons with underlying medical conditions (e.g., cardiovascular disease, diabetes, chronic respiratory disease, cancer):

  • When you have visitors in the home, exchange 1-meter (3- to 4-feet) greetings, like a wave, nod, or bow.

  • Ask visitors and those you live with to wash their hands and to cover mouth or nose when coughing or sneezing.

  • Avoid close contact and limit shared spaces with anyone who has fever and cough.

  • Regularly clean and disinfect surfaces in the home, especially areas often touched.

  • If you become ill with symptoms of COVID-19, contact your healthcare provider by telephone before visiting your healthcare facility.

  • When you go out in public, follow the same preventive guidelines as at home.


The rapidity with which the SARS-CoV-2 outbreak spread locally in China combined with the rapid accumulation of evidence for local transmission and community spread in many countries outside China suggests that human-to-human transmission is occurring from close contact with persons having mild, nonspecific symptoms. This has important public health implications. Close personal contact implies touching and the sharing of common utensils; it is also defined by a proximity of 6–8 feet—the distance aerosolized droplet nuclei travel after coughing or sneezing. Social distancing refers to behaviors designed to avoid the possibility of close personal contact.

The stability of SARS-CoV-2 on environmental surfaces has been studied in an effort to assess whether surface contamination could play a role in virus transmission. After application of aerosols containing a standard dose of SARS-CoV-2, viable virus was detected up to 72 hours on plastic and stainless steel, though the virus titer was greatly reduced; on cardboard, no viable SARS-CoV-2 was measured after 24 hours [19]. These data should be interpreted with caution, as it is unclear to what extent environmental detection of virus in much reduced titer at a given interval, experimentally, can be equated with actual risk of transmission from common environmental surfaces.

The rapidity and apparent ease with which human-to-human transmission of SARS-CoV-2 is occurring has important public health implications. Absent an effective containment strategy, the number of imported cases developing in travelers en route or recently returned from countries and regions with ongoing and widespread transmission will continue to increase, and asymptomatic returning travelers who may have been exposed to SARS-CoV-2 will be at risk for developing symptoms, and possibly exposing close contacts, anytime up to 14 days after return. Therefore, healthcare providers are encouraged to be vigilant, prepared, and cognizant of public health (i.e., CDC) recommendations for evaluation of a "person of interest" or a patient with compatible symptoms and exposure history.

With the advent or anticipation of growing numbers of COVID-19 cases in a given region, the additional public health strategy of mitigation (preventing spread within communities) becomes paramount in order to decisively limit spread and blunt the epidemic curve. These measures include the following: suspension or cancellation of events having large public gatherings, such as cinema, theatre, concerts, collegiate and professional sports competition, and political rallies; closure of schools and cancellation of classes at colleges and universities; the practice of social distancing in smaller venues such as restaurants and churches. By slowing the degree and pace of virus transmission, effective mitigation helps to protect those most vulnerable and to ensure that the clinical case load does not overwhelm local hospital and critical care resources.


The CDC is closely monitoring the COVID-19 outbreak and is providing updated epidemiologic data and clinical guidance for healthcare providers, laboratories, health facilities, and public health professionals [12]. Included are recommendations for the evaluation of persons/patients under investigation, laboratory specimen transport, and protection of healthcare workers. Recommendations for patient assessment and care in hospitals and other healthcare facilities emphasize the importance of strict adherence to patient isolation and barrier precautions, including the proper use of personal protective equipment (PPE).

The CDC website includes a COVID-19 Situation Summary regarding the number of persons under investigation in the United States, updated regularly. As of March 27, there were 85,356 positive cases and 1,246 deaths reported from 50 states, the District of Columbia, Puerto Rico, Guam, and U.S. Virgin Islands. Of the 85,356 known SARS-CoV-2 infections, 712 are travel-related, 1,326 are the result of person-to-person transmission, and 83,318 are still being investigated [12].

Selected materials from the CDC website, including recommendations for travelers, interim guidance for healthcare professionals, infection control, and healthcare worker safety, are reproduced in the following sections. Please note that language and/or cultural barriers may impede assessment and education on the topic, and interpreters and translated materials are recommended, when appropriate.

CDC Travel Notice

The CDC has established geographic risk-stratification criteria used to provide updated information about COVID-19 risk for travelers and to guide public health management decisions with respect to travel-related exposures to COVID-19 [13]. As of March 2020, CDC recommends that people avoid all nonessential travel to areas of widespread and ongoing community transmission of SARS-CoV-2. Older adults and persons with chronic medical conditions may be at increased risk for severe disease. At this time, the countries and regions included in this advisory are China, South Korea, Iran, most countries of Europe, and the United Kingdom and Ireland. Entry of foreign nationals from these destinations has been suspended, effective March 13, 2020.

The CDC travel notice is updated regularly in response to new developments. The present recommendations for those who must travel to, or have recently returned from countries and regions with sustained (ongoing) community transmission are outlined in this section [13].

Individuals who must travel should [13]:

  • Avoid contact with sick people.

  • Avoid touching your eyes, nose, or mouth with unwashed hands.

  • Wash hands often with soap and water for at least 20 seconds or use an alcohol-based hand sanitizer that contains at least 60% to 85% alcohol.

  • Avoid traveling if you are sick.

Individuals who spent time in an affected area (e.g., one of the designated countries under the travel advisory) during the past 14 days should observe the following precautions:

  • Stay home for 14 days from the time you left the area and practice social distancing.

  • Avoid contact with others; do not go to work or school for this 14-day period.

  • Do not take public transportation, taxis, or ride-shares during the time you are practicing social distancing.

  • Avoid crowded places and limit activities in public.

  • Practice social distancing (i.e., keep your distance from others—about 6 feet).

  • If you become ill with fever, cough, or trouble breathing, seek medical care right away and call ahead to inform the facility of your recent travel and your symptoms.

  • Cover your mouth and nose with a tissue or your sleeve (not your hands) when coughing or sneezing.

  • Wash hands often with soap and water for at least 20 seconds or use an alcohol-based hand sanitizer (60% to 85% alcohol) after coughing or blowing your nose.

Recommended Criteria to Guide Evaluation of Patients Under Investigation for COVID-19

The CDC encourages clinicians to use their judgment in determining if a patient has signs and symptoms compatible with COVID-19 and whether the patient should be tested [14]. Priorities for tasting may include hospitalized patients with compatible clinical features, symptomatic older adults, and patients with underlying medical conditions or immunocompromised state. Clinicians should work with their local and state health departments to coordinate testing through public health laboratories. In addition, approved COVID-19 diagnostic testing is increasingly available in clinical laboratories, allowing clinicians to consider testing for a wider group of symptomatic patients. Patients should be evaluated and discussed with public health departments on a case-by-case basis if their clinical presentation or exposure history is equivocal.

Healthcare providers in the United States should evaluate any person, including healthcare workers, for COVID-19 who has fever or signs/symptoms of respiratory illness (e.g., cough, shortness of breath) and a history of travel from an affected area within 14 days before symptom onset OR has within the past 14 days had close contact with a person with laboratory-confirmed COVID-19 [14]. Close contact is defined as one of the following:

  • Being within approximately 6 feet (2 meters), or within the room or care area, of a novel coronavirus case for a prolonged period of time while not wearing recommended personal protective equipment or PPE (e.g., gowns, gloves, certified disposable N95 respirator, eye protection); close contact can include caring for, living with, visiting, or sharing a healthcare waiting area or room with a novel coronavirus case.

  • Having direct contact with infectious secretions of a novel coronavirus case (e.g., being coughed on) while not wearing recommended personal protective equipment.

In addition, any patient with fever and severe acute lower respiratory illness (e.g., pneumonia, ARDS) requiring hospitalization and without alternative explanatory diagnosis (e.g., influenza) should be evaluated, even if no source of exposure has been identified [14].

A symptomatic patient who meets the criteria above should be provided a surgical mask and placed on respiratory isolation, preferably in an airborne isolation negative pressure room. Caregivers should observe enhanced precautions (i.e., wear gloves, gown, eye protection device [other than prescription eye glasses], and N95 respirator). For information on the management of patients with COVID-19, see https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-guidance-management-patients.html.

Diagnostic Testing

The CDC recommends that healthcare providers should immediately notify both infection control personnel at their healthcare facility and their local or state health department in the event of a person under investigation for or a suspected case of COVID-19.

Confirmation of COVID-19 is performed using the rRT-PCR assay for SARS-CoV-2 on respiratory specimens (which can include nasopharyngeal or oropharyngeal aspirates or washes, nasopharyngeal or oropharyngeal swabs, bronchoalveolar lavage, tracheal aspirates, or sputum) and serum. As of March 11, 2020, CDC reports that 81 state and local public health laboratories in 50 states have successfully verified COVID-19 diagnostic tests and are offering tests. As of March 2020, the FDA was working to expedite the availability of tests through emergency authorization of commercial laboratories that have developed SARS-CoV-2 testing capability. Information on specimen collection, handling, and storage is available at https://www.cdc.gov/coronavirus/2019-nCoV/lab/guidelines-clinical-specimens.html. After initial confirmation of COVID-19, additional testing of clinical specimens can help inform clinical management, including discharge planning. Additional guidance for collection, handling, and testing of clinical specimens is available at the CDC website [12].

Testing for other respiratory pathogens should not delay SARS-CoV-2 testing. If a PUI tests positive for another respiratory pathogen, and after clinical evaluation and consultation with public health authorities, the patient may no longer be considered a PUI. This approach may evolve as more information becomes available on possible SARS-CoV-2 co-infections.

Interim Clinical Guidance for Management of Patients with Confirmed COVID-19

Interim clinical guidance and additional resources for clinicians caring for patients with COVID-19 is provided and updated at the CDC website, selected aspects of which are reproduced in this section [15].

The clinical presentation of patients with confirmed COVID-19 has not as yet been fully characterized, as most clinical descriptions are from series of patients hospitalized with pneumonia. The expected symptoms and signs at onset of illness include fever, malaise, myalgia, and cough. Risk factors for severe illness are not yet totally clear, but older patients and those with chronic medical conditions appear to be at higher risk. From observations made in connection with reported cases of COVID-19, the clinical course varies from asymptomatic infection or mild illness to severe or fatal illness.

No specific treatment for COVID-19 is currently available. Clinical management includes prompt implementation of recommended infection prevention and control measures and supportive management of complications, including advanced organ support if indicated [15]. Corticosteroids should be avoided unless indicated for other reasons (e.g., chronic obstructive pulmonary disease exacerbation or septic shock) because of the potential for prolonging viral replication, as observed in patients with MERS-CoV.

Healthcare personnel should care for patients in an airborne infection isolation room. Standard Precautions, Contact Precautions, and Airborne Precautions and eye protection should be used when caring for the patient. For more detailed recommendations, see the CDC's Interim Infection Prevention and Control Recommendations for Patients Under Investigation for 2019 Novel Coronavirus in a Healthcare Setting at https://www.cdc.gov/coronavirus/2019-ncov/hcp/infection-control.

Patients with a mild clinical presentation may not initially require hospitalization [15]. However, clinical signs and symptoms may worsen with progression to lower respiratory tract disease in the second week of illness; all patients should be monitored closely. As noted, possible risk factors for progressing to severe illness may include, but are not limited to, older age and underlying chronic medical conditions (e.g., lung disease, cancer, heart failure, cerebrovascular disease, renal disease, liver disease, diabetes, immunocompromising conditions, pregnancy).

The CDC advises that the decision to monitor a patient in the inpatient or outpatient setting should be made on a case-by-case basis. This decision will depend not only on the clinical presentation, but also on the patient's ability to engage in monitoring and the risk of transmission in the patient's home environment. For more information, see the CDC's Criteria to Guide Evaluation of Patients Under Investigation (PUI) for COVID-19 at https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-criteria.html.

Summary of the CDC Response to the COVID-19 Outbreak

The CDC is working with the WHO and state and local public health partners to respond to this emerging public health threat. The goal of the ongoing U.S. public health response is to contain this outbreak and prevent sustained spread of COVID-19 in this country.

The CDC and Customs and Border Protection (CBP) continue to conduct enhanced entry screening of travelers who have been in an affected area within the past 14 days at 20 designated U.S. airports. Passengers having symptoms compatible with COVID-19 and a history of travel to an affected area are being referred to CDC staff for evaluation.

As of March 2020, the CDC has produced more than 23 guidance documents on infection control, hospital preparedness assessments, PPE supply planning, and clinical evaluation and management for the outbreak.

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