Important update: Healthcare facilities
CDC has updated select ways to operate healthcare systems effectively in response to COVID-19 vaccination. Learn more
Given new evidence on the B.1.617.2 (Delta) variant, CDC has updated the guidance for fully vaccinated people. CDC recommends universal indoor masking for all teachers, staff, students, and visitors to K-12 schools, regardless of vaccination status. Children should return to full-time in-person learning in the fall with layered prevention strategies in place.
The White House announced that vaccines will be required for international travelers coming into the United States, with an effective date of November 8, 2021. For purposes of entry into the United States, vaccines accepted will include FDA approved or authorized and WHO Emergency Use Listing vaccines. More information is available here.
Travel requirements to enter the United States are changing, starting November 8, 2021. More information is available here.

Interim Clinical Guidance for Management of Patients with Confirmed Coronavirus Disease (COVID-19)

Interim Clinical Guidance for Management of Patients with Confirmed Coronavirus Disease (COVID-19)
Updated Feb. 16, 2021

CDC is working on updates to this page to provide clinical considerations for the care of children and adults with confirmed Coronavirus Disease (COVID-19).

Summary of Recent Changes

This document provides guidance on caring for patients infected with SARS-CoV-2, the virus that causes COVID-19. The National Institutes of Health (NIH) have published guidelines for the clinical management of COVID-19 prepared by the COVID-19 Treatment Guidelines Panel. The recommendations are based on scientific evidence and expert opinion and are regularly updated as more data become available.

For guidance related to children with COVID-19, please see the Pediatric Considerations section below.

Clinical Presentation

Incubation period

The incubation period for COVID-19 is thought to extend to 14 days, with a median time of 4-5 days from exposure to symptoms onset.(1-3) One study reported that 97.5% of people with COVID-19 who have symptoms will do so within 11.5 days of SARS-CoV-2 infection.(3)


The signs and symptoms of COVID-19 present at illness onset vary, but over the course of the disease many people with COVID-19 will experience the following:(1,4-9)

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea

Symptoms may differ with severity of disease. For example, shortness of breath is more commonly reported among people who are hospitalized with COVID-19 than among people with milder disease (non-hospitalized patients).(10, 11) Atypical presentations of COVID-19 occur often, and older adults and people with medical comorbidities may experience fever and respiratory symptoms later during the course of illness than people who are younger or who do not have comorbidities.(12, 13) In one study of 1,099 hospitalized patients, fever was present in only 44% at hospital admission but eventually 89% of patients had a fever sometime during hospitalization.(1) Fatigue, headache, and muscle aches (myalgia) are among the most commonly reported symptoms in people who are not hospitalized, and sore throat and nasal congestion or runny nose (rhinorrhea) also may be prominent symptoms. Many people with COVID-19 experience gastrointestinal symptoms such as nausea, vomiting or diarrhea, sometimes prior to having fever and lower respiratory tract signs and symptoms.(9) Loss of smell (anosmia) or taste (ageusia) has been commonly reported, in a third of patients in one study, especially among women and younger or middle-aged patients.(14)

Dermatologic Manifestations

Dermatologic manifestations may be associated with COVID-19.(99-102) Although the frequency remains unknown, reports have ranged from 0.2%, early in the pandemic, to as high as 20.4%.(1,103-105) Association with disease severity and timing of skin symptoms among COVID-19 patients is unclear.(106-108) The clinical presentation appears varied, though in a study of 171 persons with laboratory-confirmed COVID-19 (ranging from mild to severe disease), the most common skin manifestations reported were: a maculopapular rash (22%), discolored lesions of the fingers and toes (18%), and hives (16%). Among all study participants with COVID-19 and any skin manifestations, approximately 60% reported fever and/or cough.(109)  Evaluating skin manifestations in COVID-19 patients remains challenging as symptoms can resemble a variety of other disease conditions. Additionally, COVID-19 treatments also may cause certain skin side-effects.(110) Images of cutaneous findings are available from the American Academy of Dermatology.

Asymptomatic and Presymptomatic Infection

Several studies have documented infection with SARS-CoV-2, the virus causing COVID-19, in patients who never have symptoms (asymptomatic) and in patients not yet symptomatic (presymptomatic).(15-29) Since people who are asymptomatic are not always tested, the prevalence of asymptomatic infection and detection of presymptomatic infection is not yet well understood. Current data, based on reverse transcription-polymerase chain reaction (RT-PCR) testing for SARS-CoV-2 and on serologic studies, suggest asymptomatic infections can be common and that the total number of infections is likely greater than the number of cases reported.(15,22-24,30,31) Patients may have abnormalities on chest imaging before the onset of symptoms.(16)

Asymptomatic and Presymptomatic Transmission

Increasing numbers of epidemiologic studies have documented SARS-CoV-2 transmission during the presymptomatic incubation period.(19,28,29,32) Studies using RT-PCR detection have reported low cycle thresholds, indicating larger quantities of viral RNA, among people with asymptomatic and presymptomatic SARS-CoV-2 infection. Likewise in viral culture, viral growth has been observed in specimens obtained from patients with asymptomatic and presymptomatic infection.(22,24,27,33) The proportion of SARS-CoV-2 transmission due to asymptomatic or presymptomatic infection compared with symptomatic infection is not entirely clear; however, recent studies do suggest that people who are not showing symptoms may transmit the virus.(22,24,34)

Clinical Course

Illness Severity

A large cohort that included more than 44,000 people with COVID-19 from China, showed that illness severity can range from mild to critical:(35)

  • Mild to moderate (mild symptoms up to mild pneumonia): 81%
  • Severe (dyspnea, hypoxia, or more than 50% lung involvement on imaging): 14%
  • Critical (respiratory failure, shock, or multiorgan system dysfunction): 5%

In this study, all deaths occurred among patients with critical illness, and the overall case fatality ratio (CFR) was 2.3%.(35) The CFR among patients with critical disease was 49%.(35) Among children in China, illness severity was lower than in adults, with 94% of affected children having asymptomatic, mild, or moderate disease; 5% having severe disease; and less than 1% having critical disease.(13) Among U.S. COVID-19 cases reported January 22–May 30, 2020, overall the proportion of people who were hospitalized was 14%, including 2% admitted to the intensive care unit (ICU).  Overall 5% of patients died.(36)

Clinical Progression

Among patients in multiple early studies from Wuhan, China who had severe COVID-19 illness, the median time from their onset of illness to the time they experienced dyspnea was 5–8 days; the median time from onset of illness to acute respiratory distress syndrome (ARDS) was 8–12 days; and the median time from onset of illness to ICU admission was 9.5–12 days.(5,6,37,38) Clinicians should be aware of the potential for some patients with COVID-19 to rapidly deteriorate about one week after illness onset. Among all hospitalized patients, 26%–32% of patients were admitted to the ICU.(6,8,38) Among all patients, 3%–17% had ARDS compared with 20%–42% for hospitalized patients and 67%–85% for patients admitted to the ICU.(1,4-6,8,38) Mortality among patients admitted to the ICU ranged from 39% to 72% depending on the study and characteristics of patient population.(5,8,37,38) The median length of hospitalization among survivors was 10–13 days.(1,6,8)

Risk Factors for Severe Illness

Age is a strong risk factor for severe illness, complications, and death.(1,6,8,13,34,35,39-42) Among the cohort of more than 44,000 confirmed cases of COVID-19 in China, the CFR increased with advancing age, and was highest among the oldest cohort.  Mortality among people 80 years and older was 14.8%; 70–79 years, 8.0%; 60–69 years, 3.6%; 50–59 years, 1.3%; 40–49 years, 0.4%; and for those younger than 40 years, 0.2%.(35) Based on U.S. epidemiologic data through March 16, 2020, CFR was highest in people aged 85 years or older (range 10%–27%), followed by people aged 65–84 years (3%–11%), aged 55–64 years (1%–3%), and was lower in people younger than 55 years (<1%).(39)

CFR in the large cohort in China was elevated for patients with comorbidities, with 10.5% of those with underlying cardiovascular disease, 7.3% of those with diabetes, 6.3% of those with chronic respiratory disease, and 5.6% of those with cancer dying of COVID-related illness.(35)  Prior stroke, diabetes, chronic lung disease, and chronic kidney disease have all been associated with increased illness severity and adverse outcomes due to COVID-19.  Heart conditions, including heart failure, coronary artery disease, cardiomyopathies, and pulmonary hypertension, put people at higher risk for severe illness from COVID-19. People with hypertension may be at an increased risk for severe illness from COVID-19 and should continue to take their medications as prescribed. (43)

Accounting for differences in age and prevalence of underlying conditions, the mortality associated with COVID-19 that has been reported in the United States appears similar to reports from China.(36, 39) See People Who Are at Increased Risk for Severe Illness to learn more about who is at increased risk.


To date, limited data exist about reinfection with SARS-CoV-2 after recovery from COVID-19.(44-46) Published case reports have shown that reinfection is possible, but it is still unclear how long people who have recovered from COVID-19 are protected against reinfection with SARS-CoV-2, what concentration of antibodies is needed to confer protection, and how often reinfection may occur.(44-46) COVID-19 has been correlated with the detection of IgM and IgG antibodies to SARS-CoV-2.(48-51) COVID-19 has been correlated with the detection of IgM and IgG antibodies to SARS-CoV-2.(48-51) Reinfection with a SARS-CoV-2 variant virus has been reported in Brazil, (116-118) the U.K., (119) and South Africa. (120) The risk of reinfection may be increased in the future with exposure to SARS-CoV-2 variant virus strains that are not neutralized by immune antisera, such as one recently described in South Africa. (121)

Prolonged Detection of SARS-CoV-2

While viral RNA shedding declines with resolution of symptoms, SARS-CoV-2 RNA shedding may continue for days to weeks.(37,47,48) Thus, detection of viral RNA during convalescence does not necessarily indicate replication-competent virus (infectiousness) or the presence of new infectious virus. Some people who have recovered may have detectable SARS-CoV-2 RNA in upper respiratory specimens for up to 3 months after illness onset, albeit at concentrations considerably lower than during illness, in ranges where replication-competent virus has not been reliably recovered and infectiousness is unlikely. Some people with severe illness might produce replication-competent virus beyond 10 days that may warrant extending duration of isolation and precautions for up to 20 days after symptom onset. Limited data suggest that some severely immunocompromised patients (e.g., patients with lymphoma, hypogammaglobulinemia, hemopoietic stem cell transplant recipients, AIDS, those receiving immunosuppression with chemotherapy, systemic corticosteroids and biologics) might produce replication-competent virus beyond 20 days and require additional testing and consultation with infectious diseases specialists and infection control experts.(111-115) For more information about duration of viral shedding among people with SARS-CoV-2 infection, see Duration of Isolation and Precautions for Adults with COVID-19 Also see CDC’s Investigative Criteria for Suspected Cases of SARS-CoV-2 Reinfection as well as the Common Investigation Protocol for Investigating Suspected SARS-CoV-2 Reinfection.

Laboratory and Radiographic Findings

Testing for Infection

Diagnosis of COVID-19 requires detection of SARS-CoV-2 RNA or antigen in respiratory specimens. Detection of SARS-CoV-2 viral RNA is better in nasopharynx samples compared with throat samples.(32,47,52) Lower respiratory samples may have better viral yield than upper respiratory samples.(53) SARS-CoV-2 antigen tests can also be used in a variety of testing strategies. See Interim Guidance for Rapid Antigen Testing for SARS-CoV-2 for more information about the effective use of antigen tests in different testing situations. SARS-CoV-2 RNA has also been detected in stool and blood.(51,54) Detection of SARS-CoV-2 RNA in blood may be a marker of severe illness.(55)

Infection with both SARS-CoV-2 and with other respiratory viruses (e.g., influenza) or bacteria is well documented, and detection of another respiratory pathogen does not rule out COVID-19.(56)  Clinicians are encouraged to consider testing for other viral causes of respiratory illness, for example influenza, in addition to testing for SARS-CoV-2 depending on patient age, season, or clinical setting. Clinicians should also consider bacterial and fungal causes of pneumonia (e.g. Legionnaires’ disease in patients exposed to water from previously closed buildings or overnight travel, pneumococcal pneumonia, and coccidioidomycosis) in patients who are PCR-negative for SARS CoV-2, as clinically indicated. See IDSA/ATS guidelines.

For more information about COVID-19 testing and specimen collection, handling and storage, visit Frequently Asked Questions about COVID-19 for Laboratories.

Other Laboratory Findings

Lymphopenia is the most common laboratory finding among people with COVID-19 and is found in up to 83% of hospitalized patients.(1,5) Lymphopenia, neutrophilia, elevated serum alanine aminotransferase and aspartate aminotransferase levels, elevated lactate dehydrogenase, high C-reactive protein (CRP), and high ferritin levels may be associated with greater illness severity.(1,5,6,8) Elevated D-dimer and lymphopenia have been associated with mortality.(8,37,57,58) Procalcitonin is typically normal on admission but may increase among those patients admitted to an ICU.(4-6) Patients with critical illness had high plasma levels of inflammatory makers, suggesting potential immune dysregulation.(5,59)

Radiographic Findings

Chest radiographs of patients with COVID-19 typically demonstrate bilateral air-space consolidation, although some patients have unremarkable chest radiographs early in the disease.(1,47) Chest Computerized Tomography (CT) images from patients with COVID-19 typically demonstrate bilateral, peripheral ground glass opacities.(60-71) Because this chest CT imaging pattern is non-specific and can be found in pneumonias caused by other infections, the diagnostic value of chest CT imaging for COVID-19 may be low and dependent upon radiographic interpretation.(70) One study found that 56% of patients who presented within two days of diagnosis had a normal CT.(62) Conversely, other studies have identified chest CT abnormalities in patients prior to the detection of SARS-CoV-2 RNA in RT-PCR testing of nasopharyngeal samples.(71) Given the variability in chest imaging findings, chest radiograph or CT alone is not recommended for the diagnosis of COVID-19. The American College of Radiology also does not recommend CT for screening, or as a first-line test for diagnosis of COVID-19. (See American College of Radiology Recommendations).

Clinical Management and Treatment

The National Institutes of Health (NIH) published guidelines on prophylaxis use, testing, and management of patients with COVID-19. For more information, please visit the NIH Coronavirus Disease 2019 (COVID-19) Treatment Guidelines. The recommendation are based on scientific evidence and expert opinion and are regularly updated as more data become available. The U.S. Food and Drug Administration (FDA) has approved remdesivir (Veklury) for the treatment of COVID-19 in certain situations. Clinical management of COVID-19 includes infection prevention and control measures and supportive care, including supplemental oxygen and mechanical ventilatory support when indicated.

Mild to Moderate Disease

Patients with a mild clinical presentation (absence of viral pneumonia and hypoxia) may not initially require hospitalization, and most patients will be able to manage their illness at home. 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 on the clinical presentation, requirement for supportive care, potential risk factors for severe disease, and the ability of the patient to self-isolate at home. Patients with risk factors for severe illness (see People Who Are at an Increased Risk for Severe Illness) should be monitored closely given the possible risk of progression to severe illness, especially in the second week after symptom onset.(5,6,35)

In certain clinical settings, pulse oximetry is used to assess and monitor a patient’s oxygenation status. Clinicians should be aware that pulse oximeters may exhibit suboptimal accuracy in certain populations.(92,93) Limited data from studies with small numbers of participants suggest that skin pigmentation can affect pulse oximeter accuracy.(94-97)  One study published in December, 2020, used self-reported race data and compared pulse oximetry to arterial oxygen saturation measurement in two adult inpatient cohorts that were receiving supplemental oxygen. These cohorts included 1,333 White patients and 276 Black patients in one university hospital during January through July 2020, and 7,342 White patients and 1,050 Black patients in intensive care units at 178 hospitals during 2014-2015. The authors reported that occult hypoxemia (defined in the study as “arterial oxygen saturation of <88% by arterial blood gas despite oxygen saturation of 92 to 96% on pulse oximetry”) was not detected by pulse oximetry nearly three times more frequently in Black patients than White patients.(98) This study  highlights the importance of assessing other factors (e.g., high-risk conditions, observed signs and symptoms) rather than relying on pulse oximetry measurement alone when assessing, triaging, and managing patients with suspected or laboratory-confirmed COVID-19.

For information regarding infection prevention and control recommendations, please see Infection Control Guidance for Healthcare Professionals about Coronavirus (COVID-19).

Severe Disease

Some patients with COVID-19 will have severe disease requiring hospitalization for management. Inpatient management includes supportive management of the most common complications of severe COVID-19: pneumonia, hypoxemic respiratory failure/ARDS, sepsis and septic shock, cardiomyopathy and arrhythmia, acute kidney injury, and complications from prolonged hospitalization, including secondary bacterial and fungal infections, thromboembolism, gastrointestinal bleeding, and critical illness polyneuropathy/myopathy.(1,4-6,13,35,40,72-74)

More information can be found at  Clinical Questions about COVID-19: Questions and Answers. Additional resources and guidance documents on the treatment and management of COVID-19, including inpatient management of critically ill patients, are provided below.

Hypercoagulability and COVID-19

Some patients with COVID-19 may have signs of a hypercoagulable state and be at increased risk for venous and arterial thrombosis of large and small vessels.(57,58,75-80) Laboratory abnormalities commonly observed among hospitalized patients with COVID-19-associated coagulopathy include:

  • Mild thrombocytopenia
  • Increased D-dimer levels
  • Increased fibrin degradation products
  • Prolonged prothrombin time

Elevated D-dimer levels have been strongly associated with greater risk of death.(8,37,57,58)

There are several reports of hospitalized patients with thrombotic complications, most frequently deep venous thrombosis and pulmonary embolism.(58,75-77) Other reported manifestations include:

  • Microvascular thrombosis of the toes (“COVID toes”)
  • Clotting of intra-vascular catheters
  • Myocardial injury with ST-segment elevation
  • Large vessel strokes(78,79)

The pathogenesis for COVID-19-associated hypercoagulability is incompletely understood. However, hypoxia and systemic inflammation secondary to COVID-19 may lead to high levels of inflammatory cytokines and activation of the coagulation pathway.(81)

Data available to inform clinical management around prophylaxis or treatment of venous thromboembolism in COVID-19 patients are still evolving, with new information released often.  Several national professional associations provide resources for up-to-date information concerning COVID-19-associated hypercoagulability, including management of anticoagulation. More information on hypercoagulability and COVID-19 is available from the American Society of Hematology and National Institutes of Health.

Pediatric Considerations

Increasingly, data indicate that the clinical symptoms experienced by children with COVID-19 are similar to adults, but disease is usually milder than adults and severity of symptoms varies by age of the child. Many children infected with SARS-CoV-2 remain asymptomatic or have mild illness.(82,83) Commonly reported symptoms in children with COVID-19 include cough or fever, and many children also experience gastrointestinal or other symptoms.(84-88) Even though most children with COVID-19 have asymptomatic or mild illness, severe outcomes, including deaths, have been reported in children.(89) Children of all ages with certain underlying medical conditions may be at increased risk of severe illness; also infants (<12 months of age) may be at increased risk for severe illness from COVID-19.(89, 90)

CDC and partners are investigating the multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19. Patients with MIS-C usually present with persistent fever, abdominal pain, vomiting, diarrhea, skin rash, mucocutaneous lesions and, in severe cases, hypotension and shock. Affected children have elevated laboratory markers of inflammation (e.g., CRP, ferritin), and a majority of patients have laboratory markers of damage to the heart (e.g., troponin; B-type natriuretic peptide (BNP) or proBNP). Some patients have myocarditis, cardiac dysfunction, and acute kidney injury. Not all children with MIS-C experience the same signs and symptoms, and some children may have symptoms not listed here. MIS-C may begin weeks after a child was infected with SARS-CoV-2. The child might have been infected from an asymptomatic contact and, in some cases, the child and their caregivers might not realize that the child had been infected.

For expanded considerations on the care of children with confirmed or suspected COVID-19 and associated complications, refer to:

Investigational Therapeutics

The National Institutes of Health have published guidelines for the medical management of COVID-19 prepared by the COVID-19 Treatment Guidelines Panel. These guidelines contain information about therapeutics and will be updated as new information emerges and drugs and other therapeutic interventions are approved for use by FDA. Persons seeking information about registered clinical trials for COVID-19 in the United States can search for such information here:

Discontinuation of Transmission-Based Precautions or Home Isolation

Patients who have clinically recovered and are able to discharge from the hospital, but who have not been cleared from their Transmission-Based Precautions, can continue isolation at their place of residence until cleared. For recommendations on discontinuation of Transmission-Based Precautions or home isolation for patients who have recovered from COVID-19, see:

Previous Updates

  1. Guan WJ, Ni ZY, Hu Y, et al. Clinical Characteristics of Coronavirus Disease 2019 in China. N Engl J Med. 2020 Apr 30;382:1708–1720. doi:10.1056/NEJMoa2002032.
  2. Li Q, Guan X, Wu P, et al. Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus-Infected Pneumonia. N Engl J Med. 2020 Mar 26;382:1199–207. doi:10.1056/nejmoa2001316.
  3. Lauer SA, Grantz KH, Bi Q, et al. The Incubation Period of Coronavirus Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases: Estimation and Application. Ann Intern Med. 2020 May 5;172(9):577–82. doi:10.7326/M20-0504.
  4. Chen N, Zhou M, Dong X, et al. Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study. Lancet. 2020 Feb;395:507–13. doi:10.1016/S0140-6736(20)30211-7.
  5. Huang C, Wang Y, Li X, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020 Feb;395:497–506. doi:10.1016/S0140-6736(20)30183-5.
  6. Wang D, Hu B, Hu C, et al. Clinical Characteristics of 138 Hospitalized Patients With 2019 Novel Coronavirus-Infected Pneumonia in Wuhan, China. JAMA. 2020 Feb 7.;323(11):1061–9. doi:10.1001/jama.2020.1585.
  7. Xu XW, Wu XX, Jiang XG, et al. Clinical findings in a group of patients infected with the 2019 novel coronavirus (SARS-Cov-2) outside of Wuhan, China: retrospective case series. BMJ. 2020 Feb 19;368:m606. doi:10.1136/bmj.m606.
  8. Wu C, Chen X, Cai Y, et al. Risk Factors Associated With Acute Respiratory Distress Syndrome and Death in Patients With Coronavirus Disease 2019 Pneumonia in Wuhan, China. JAMA Intern Med. 2020 Mar 13;180(7):934–43. doi:10.1001/jamainternmed.2020.0994.
  9. Pan L, Mu M, Yang P, et al. Clinical Characteristics of COVID-19 Patients With Digestive Symptoms in Hubei, China: A Descriptive, Cross-Sectional, Multicenter Study. Am J Gastroenterol. 2020 May;115(5):766–73. doi:10.14309/ajg.0000000000000620.
  10. Killerby ME, Link-Gelles R, Haight SC, et al. Characteristics Associated with Hospitalization Among Patients with COVID-19 — Metropolitan Atlanta, Georgia, March–April 2020. MMWR. 2020 Jun 26; 69:790–794. doi:10.15585/mmwr.mm6925e1.
  11. Tenforde MW, Rose EB, Lindsell CJ, et al. Characteristics of Adult Outpatients and Inpatients with COVID-19 —– 11 Academic Medical Centers, United States, March––May 2020. MMWR. 2020 Jul 3;69:841-846. doi:10.15585/mmwr.mm6926e3.
  12. Cai J, Xu J, Lin D, et al. A Case Series of children with 2019 novel coronavirus infection: clinical and epidemiological features. Clin Infect Dis 2020;71(6):1547–-1551. doi:10.1093/cid/ciaa198.
  13. Dong Y, Mo X, Hu Y, et al. Epidemiology of COVID-19 Among Children in China. Pediatrics. 2020 Jun;145(6): e20200702. doi:10.1542/peds.2020-0702.
  14. Giacomelli A, Pezzati L, Conti F, et al. Self-reported olfactory and taste disorders in SARS-CoV-2 patients: a cross-sectional study. Clin Infect Dis. 2020 Aug;71(15):889–-890. doi:10.1093/cid/ciaa330.
  15. Lu X, Zhang L, Du H, et al. SARS-CoV-2 Infection in Children. N Engl J Med. 2020 Apr 23;382:1663-5. doi:10.1056/NEJMc2005073.
  16. Chan JF, Yuan S, Kok KH, et al. A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster. Lancet. 2020 Feb;395:514–-23. doi:10.1016/S0140-6736(20)30154-9.
  17. Hu Z, Song C, Xu C, et al. Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing, China. Sci China Life Sci. 2020 Mar 4;63:706–-11. doi:10.1007/s11427-020-1661-4.
  18. Wang Y, Liu Y, Liu L, Wang X, Luo N, Ling L. Clinical outcome of 55 asymptomatic cases at the time of hospital admission infected with SARS-Coronavirus-2 in Shenzhen, China. J Infect Dis. 2020 Jun 1. doi:10.1093/infdis/jiaa119.
  19. Pan X, Chen D, Xia Y, et al. Asymptomatic cases in a family cluster with SARS-CoV-2 infection. Lancet Infect Dis. 2020 Apr;20:410—1. doi:10.1016/S1473-3099(20)30114-6.
  20. Bai Y, Yao L, Wei T, et al. Presumed Asymptomatic Carrier Transmission of COVID-19. JAMA. 2020 Feb 21;323(14):1406-1407. doi:10.1001/jama.2020.2565.
  21. Kam KQ, Yung CF, Cui L, et al. A Well Infant with Coronavirus Disease 2019 (COVID-19) with High Viral Load. Clin Infect Dis. 2020 Aug 1;71(15):847–9. doi:10.1093/cid/ciaa201.
  22. Kimball A, Hatfield KM, Arons M, 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. 2020 Mar 27;69:377-81. doi:10.15585/mmwr.mm6913e1.
  23. Roxby AC, Greninger AL, Hatfield KM, et al. Detection of SARS-CoV-2 Among Residents and Staff Members of an Independent and Assisted Living Community for Older Adults —– Seattle, Washington, 2020. MMWR. 2020 Apr 3;69:416–8. doi:10.15585/mmwr.mm6914e2.
  24. Mizumoto K, Kagaya K, Zarebski A, Chowell G. Estimating the asymptomatic proportion of coronavirus disease 2019 (COVID-19) cases on board the Diamond Princess cruise ship, Yokohama, Japan, 2020. Euro Surveill. 2020 Feb 5;25. doi:10.2807%2F1560-7917.ES.2020.25.10.2000180.
  25. Hoehl S, Rabenau H, Berger A, et al. Evidence of SARS-CoV-2 Infection in Returning Travelers from Wuhan, China. N Engl J Med. 2020 Mar 26;382:1278–80. doi:10.1056/NEJMc2001899.
  26. Wei WE, Li Z, Chiew CJ, Yong SE, Toh MP, Lee VJ. Presymptomatic Transmission of SARS-CoV-2 —– Singapore, January 23–-March 16, 2020. MMWR. 2020 Apr 1;69:411-5. doi:10.15585/mmwr.mm6914e1.
  27. Tong ZD, Tang A, Li KF, et al. Potential Presymptomatic Transmission of SARS-CoV-2, Zhejiang Province, China, 2020. Emerg Infect Dis. 2020 May;26:1052–4. doi:10.3201/eid2605.200198.
  28. Qian G, Yang N, Ma AHY, et al. A COVID-19 Transmission within a family cluster by presymptomatic infectors in China. Clin Infect Dis. 2020 Mar 23;71(15):861–2. org:10.1093/cid/ciaa316.
  29. Rothe C, Schunk M, Sothmann P, et al. Transmission of 2019-nCoV Infection from an Asymptomatic Contact in Germany. N Engl J Med. 2020 Mar 5;382:970–1. doi: 10.1056/NEJMc2001468.
  30. Havers, F.P., Reed, C., Lim, T., Montgomery, J.M., Klena, J.D., Hall, A.J., Fry, A.M., Cannon, D.L., Chiang, C.F., Gibbons, A. and Krapiunaya, I. Seroprevalence of antibodies to SARS-CoV-2 in 10 sites in the United States, March 23–May 12, 2020. JAMA Internal Medicine. 2020 Jul 21. doi:10.1001/jamainternmed.2020.4130.
  31. Rosenberg ES, Tesoriero JM, Rosenthal EM, et al. Cumulative incidence and diagnosis of SARS-CoV-2 infection in New York. Ann Epidemiol. 2020 Aug;48:23–9. doi:10.1016/j.annepidem.2020.06.004.
  32. Zou L, Ruan F, Huang M, et al. SARS-CoV-2 Viral Load in Upper Respiratory Specimens of Infected Patients. N Engl J Med. 2020 Mar 19;382:1177–9. org:10.1056/NEJMc2001737.
  33. Arons M.M., Hatfield K.M., Reddy S.C., Kimball A., James A., Jacobs J.R. Presymptomatic SARS-CoV-2 Infections and Transmission in a Skilled Nursing Facility. N Engl J Med. 2020 May 28;382:2081–90. doi:10.1056/NEJMoa2008457.
  34. Li R, Pei S, Chen B, et al. Substantial undocumented infection facilitates the rapid dissemination of novel coronavirus (SARS-CoV-2). Science. 2020 May 1;368(6490):489–93.
  35. Wu 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 Feb 24;323(13):1239–42. doi:10.1001/jama.2020.2648.
  36. Stokes EK, Zambrano LD, Anderson KN, et al. Coronavirus Disease 2019 Case Surveillance — United States, January 22–May 30, 2020. MMWR. 2020 Jun 19;69:759–765. doi:10.15585/mmwr.mm6924e2.
  37. Zhou F, Yu T, Du R, et al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. 2020 Jun;395:1054–62.
  38. Yang X, Yu Y, Xu J, 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 Apr; 8(5):475–81.
  39. Bialek S, Boundy E, Bowen V, et al. Severe Outcomes Among Patients with Coronavirus Disease 2019 (COVID-19) — United States, February 12–March 16, 2020. MMWR. 2020 Mar 18;69:343-6. doi:10.15585/mmwr.mm6912e2.
  40. Arentz M, Yim E, Klaff L, et al. Characteristics and Outcomes of 21 Critically Ill Patients With COVID-19 in Washington State. JAMA. 2020 Mar 19;323(16)1612–4. doi:10.1001/jama.2020.4326.
  41. Livingston E, Bucher K. Coronavirus Disease 2019 (COVID-19) in Italy. JAMA. 2020 Mar 17;323(14):1335. doi:10.1001/jama.2020.4344.
  42. Jackson BR et al., Predictors at admission of mechanical ventilation and death in an observational cohort of adults hospitalized with COVID-19. Clinical Infectious Diseases. 2020 Sep 24; ciaa1459. doi:10.1093/cid/ciaa1459.
  43. Chow N, Fleming-Dutra K, Gierke R, et al. Preliminary Estimates of the Prevalence of Selected Underlying Health Conditions Among Patients with Coronavirus Disease 2019 — United States, February 12–March 28, 2020. MMWR. 2020 Mar 31;69:382–6. doi:10.15585/mmwr.mm6913e2.
  44. To KK, Hung IF, Ip JD, et al. COVID-19 re-infection by a phylogenetically distinct SARS-coronavirus-2 strain confirmed by whole genome sequencing. Clin Infect Dis. 2020 Aug 25; ciaa1275. doi:10.1093/cid/ciaa1275.
  45. Tillett R, Sevinsky J, Hartley P, et al. Genomic Evidence for a Case of Reinfection with SARS-CoV-2. SSRN. 2020 Aug 31. Available at: doi:10.2139/ssrn.3680955.
  46. Van Elslande JV, Vermeersch P, Vandervoort K, et al. Symptomatic SARS-CoV-2 reinfection by a phylogenetically distinct strain. Clinical Infectious Diseases. 2020 Sep 5; ciaa1330. doi:10.1093/cid/ciaa1330.
  47. Young BE, Ong SWX, Kalimuddin S, et al. Epidemiologic Features and Clinical Course of Patients Infected With SARS-CoV-2 in Singapore. JAMA. 2020 Mar 3;323(15):1488–94. doi:10.1001/jama.2020.3204.
  48. Zhao J, Yuan Q, Wang H, et al. Antibody responses to SARS-CoV-2 in patients of novel coronavirus disease 2019. Clin Infect Dis. 2020 May 28. doi:10.1093/cid/ciaa344.
  49. Zhang W, Du RH, Li B, et al. Molecular and serological investigation of 2019-nCoV infected patients: implication of multiple shedding routes. Emerg Microbes Infect. 2020 Feb 7;9:386–9. doi:10.1080/22221751.2020.1729071.
  50. Guo L, Ren L, Yang S, et al. Profiling Early Humoral Response to Diagnose Novel Coronavirus Disease (COVID-19). Clin Infect Dis. 2020 Aug;71(15):778–85. doi:10.1093/cid/ciaa310.
  51. Wang W, Xu Y, Gao R, et al. Detection of SARS-CoV-2 in Different Types of Clinical Specimens. JAMA. 2020 Mar 11;323(18):1843-33. doi:10.1001/jama.2020.3786.
  52. To KK, Tsang OT, Leung WS, 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 May;20(5):565–74. doi:10.1016/S1473-3099(20)30196-1.
  53. Mohammadi A, Esmaeilzadeh E, Li Y, Bosch RJ, Li J. SARS-CoV-2 Detection in Different Respiratory Sites: A Systematic Review and Meta-Analysis. EBioMedicine. 2020 Sep;59(102903). doi:10.1016/j.ebiom.2020.102903.
  54. Zhang C, Shi L, Wang FS. Liver injury in COVID-19: management and challenges. Lancet Gastroenterol Hepatol. 2020 May;5:428–30. doi:10.1016/S2468-1253(20)30057-1.
  55. Chen W, Lan Y, Yuan X, et al. Detectable 2019-nCoV viral RNA in blood is a strong indicator for the further clinical severity. Emerg Microbes Infect. 2020 Feb 25;9:469–73. doi:10.1080/22221751.2020.1732837.
  56. Ding Q, Lu P, Fan Y, Xia Y, Liu M. The clinical characteristics of pneumonia patients coinfected with 2019 novel coronavirus and influenza virus in Wuhan, China. J Med Virol. 2020 Mar 20;92(9):1549-1555. doi:10.1002/jmv.25781.
  57. Tang N, Li D, Wang X, Sun Z. Abnormal coagulation parameters are associated with poor prognosis in patients with novel coronavirus pneumonia. J Thromb Haemost. 2020 Feb 19;18(4). doi:10.1111/jth.14768.
  58. American Venous Forum. Considerations in prophylaxis and treatment of VTE in COVID-19 Patients. 2020. Accessed April 2020 at
  59. Qin C, Zhou L, Hu Z, et al. Dysregulation of immune response in patients with COVID-19 in Wuhan, China. Clin Infect Dis. 2020 Mar 12;71(15):762–8). doi:10.1093/cid/ciaa248.
  60. Shi H, Han X, Jiang N, et al. Radiological findings from 81 patients with COVID-19 pneumonia in Wuhan, China: a descriptive study. Lancet Infect Dis. 2020 Apr;20:425–34. doi:10.1016/S1473-3099(20)30086-4.
  61. Ai T, Yang Z, Hou H, et al. Correlation of Chest CT and RT-PCR Testing in Coronavirus Disease 2019 (COVID-19) in China: A Report of 1014 Cases. Radiology. 2020 Feb 26;296(2):E32–E40. doi:10.1148/radiol.2020200642.
  62. Bernheim A, Mei X, Huang M, et al. Chest CT Findings in Coronavirus Disease-19 (COVID-19): Relationship to Duration of Infection. Radiology. 2020 Feb 20;295(3):685–91. doi:10.1148/radiol.2020200463.
  63. Lei J, Li J, Li X, Qi X. CT Imaging of the 2019 Novel Coronavirus (2019-nCoV) Pneumonia. Radiology. 2020 Jan 31;295(1):18. doi:10.1148/radiol.2020200236.
  64. Shi H, Han X, Zheng C. Evolution of CT Manifestations in a Patient Recovered from 2019 Novel Coronavirus (2019-nCoV) Pneumonia in Wuhan, China. Radiology. 2020 Feb 7;295(1):20. doi:10.1148/radiol.2020200269.
  65. Wang Y, Dong C, Hu Y, et al. Temporal Changes of CT Findings in 90 Patients with COVID-19 Pneumonia: A Longitudinal Study. Radiology. 2020 Mar 19;296(2):E55–-E64. doi:10.1148/radiol.2020200843.
  66. Xu X, Yu C, Qu J, et al. Imaging and clinical features of patients with 2019 novel coronavirus SARS-CoV-2. Eur J Nucl Med Mol Imaging. 2020 Feb 28;47:1275–80. doi:10.1007/s00259-020-04735-9.
  67. Yang W, Cao Q, Qin L, et al. Clinical characteristics and imaging manifestations of the 2019 novel coronavirus disease (COVID-19):A multi-center study in Wenzhou city, Zhejiang, China. J Infect. 2020 Apr;80(4):388–93. doi:10.1016/j.jinf.2020.02.016.
  68. Zhao W, Zhong Z, Xie X, Yu Q, Liu J. Relation Between Chest CT Findings and Clinical Conditions of Coronavirus Disease (COVID-19) Pneumonia: A Multicenter Study. Am J Roentgenol. 2020 May;214(5):1072–7. doi:10.2214/AJR.20.22976.
  69. Pan F, Ye T, Sun P, et al. Time Course of Lung Changes On Chest CT During Recovery From 2019 Novel Coronavirus (COVID-19) Pneumonia. Radiology. 2020 Feb 13;295(3):715–21. doi:10.1148/radiol.2020200370.
  70. Bai HX, Hsieh B, Xiong Z, et al. Performance of radiologists in differentiating COVID-19 from viral pneumonia on chest CT. Radiology. 2020 Mar 10;296(2): E46–E54. doi:10.1148/radiol.2020200823.
  71. Xie X, Zhong Z, Zhao W, Zheng C, Wang F, Liu J. Chest CT for Typical 2019-nCoV Pneumonia: Relationship to Negative RT-PCR Testing. Radiology. 2020 Feb 12;296(2): E41–E45. doi:10.1148/radiol.2020200343.
  72. Guo T, Fan Y, Chen M, et al. Cardiovascular Implications of Fatal Outcomes of Patients With Coronavirus Disease 2019 (COVID-19). JAMA Cardiol. 2020 Mar 27;5(7): 811–818. doi:10.1001/jamacardio.2020.1017.
  73. Inciardi RM, Lupi L, Zaccone G, et al. Cardiac Involvement in a Patient With Coronavirus Disease 2019 (COVID-19). JAMA Cardiol. 2020 Mar 27;5(7):811–8. doi:10.1001/jamacardio.2020.1017.
  74. Shi S, Qin M, Shen B, et al. Association of Cardiac Injury With Mortality in Hospitalized Patients With COVID-19 in Wuhan, China. JAMA Cardiol. 2020 Mar 25;5(7):802–10. doi:10.1001/jamacardio.2020.0950.
  75. Klok, FA; Kruip, MJHA; van der Meer NJM et al. Incidence of thrombotic complications in critically ill ICU patients with COVID-19. Thrombosis Research. 2020 Jul;191:145–7. doi:10.1016/j.thromres.2020.04.013.
  76. Helms, J; Tacquard, C; Severac, F et al.  High risk of thrombosis in patients in severe SARS-CoV-2 infection: a multicenter prospective cohort study. Intensive Care Medicine. 2020 May 4;46(6):1089–8. doi:10.1007/s00134-020-06062-x.
  77. Grillet, F; Behr, J; Calame, H et al.  Acute Pulmonary Embolism Associated with COVID-19 Pneumonia Detected by Pulmonary CT Angiography. Radiology 2020. Apr 23;296(3):E186–E188. doi:10.1148/radiol.2020201544.
  78. Oxley, T; Mocco, J; Majidi,S et al. Large-Vessel Stroke as a Presenting Feature of Covid-19 in the Young. N Engl J Med. 2020 Apr 28;382:e60. doi:10.1056/NEJMc2009787.
  79. Li, Y; Wang, M; Zhou, Y et al.  Acute Cerebrovascular Disease Following COVID-19: A Single Center, Retrospective, Observational Study. Stroke Vasc Neurol. 2020 Jul 2;5(3):e000431. doi:10.1136/svn-2020-000431.
  80. Margo,C; Mulvey, J; Berlin, D et al. Complement associated microvascular injury and thrombosis in the pathogenesis of severe COVID-19 infection: A report of five cases. Translational Research. 2020 Jun;220:1–13. doi:10.1016/j.trsl.2020.04.007.
  81. Merad, M., Martin, J.C. Pathological inflammation in patients with COVID-19: a key role for monocytes and macrophages. Nat Rev Immunol. 2020 May 6;20:355–62. doi:10.1038/s41577-020-0331-4.
  82. Assaker, Rita, et al. Presenting symptoms of COVID-19 in children: a meta-analysis of published studies. British Journal of Anaesthesia. 2020 Sep;125(3):E330–E332. doi:10.1016/j.bja.2020.05.026.
  83. Poline et al. Systematic SARS-CoV-2 screening at hospital admission in children: A French prospective multicenter study. Clinical Infectious Disease. 2020 Jul 25:ciaa1044. doi:10.1093/cid/ciaa1044.
  84. Dong Y, Mo X, Hu Y, et al. Epidemiology of COVID-19 Among Children in China. Pediatrics.2020 Jun. doi:10.1542/peds.2020-0702.
  85. Foster CE, Moulton EA, Munoz FM, et al. Coronavirus Disease 2019 in Children Cared for at Texas Children’s Hospital: Initial Clinical Characteristics and Outcomes. Journal of the Pediatric Infectious Diseases Society.2020 Jun 6;9(3):373–7. doi:10.1093/jpids/piaa072.
  86. Xu H, Liu E, Xie J, et al. A follow up study of children infected with SARS-CoV-2 from Western China. Annals of Translational Medicine. 2020 May;8(10):623. doi:10.21037/atm-20-3192.
  87. Shekerdemian LS, Mahmood NR, Wolfe KK, et al. Characteristics and Outcomes of Children With Coronavirus Disease 2019 (COVID-19) Infection Admitted to US and Canadian Pediatric Intensive Care Units. JAMA Pediatrics. 2020 May 11;174(9):868–73. doi:10.1001/jamapediatrics.2020.1948.
  88. Mannheim J, Gretsch S, Layden JE, Fricchione MJ. Characteristics of Hospitalized Pediatric COVID-19 Cases — Chicago, Illinois, March–April 2020. J Pediatric Infect Dis Soc. 2020 Jun 1; piaa070. doi:10.1093/jpids/piaa070.
  89. Kim L, Whitaker M, O’Halloran A, et al. Hospitalization Rates and Characteristics of Children Aged <18 Years Hospitalized with Laboratory-Confirmed COVID-19 — COVID-NET, 14 States, March 1–July 25, 2020. MMWR. 2020 Aug 14;69(32):1081–88. doi:10.15585/mmwr.mm6932e3.
  90. Bellino S, et al. COVID-19 Disease Severity Risk Factors for Pediatric Patients in Italy. Pediatrics. 2020 Oct;146(4):e2020009399. doi:10.1542/peds.2020-009399.
  91. Horby, Peter, et al. Dexamethasone in Hospitalized Patients with Covid-19 — Preliminary Report. N Engl J Med. 2020 Jul 17. doi:10.1056/NEJMoa2021436.
  92. Luks AM, Swenson ER. Pulse Oximetry for Monitoring Patients with COVID-19 at Home. Potential Pitfalls and Practical Guidance. Ann Am Thorac Soc. 2020 Sep;17(9):1040-1046. doi:10.1513/AnnalsATS.202005-418FR
  93. Philip KEJ, Bennett B, Fuller S, et al. Working accuracy of pulse oximetry in COVID-19 patients stepping down from intensive care: a clinical evaluation. BMJ Open Respir Res. 2020 Dec;7(1):e000778. doi:101136/bmjresp-2020-000778
  94. Jubran A, Tobin MJ.Reliability of pulse oximetry in titrating supplemental oxygen therapy in ventilator-dependent patients. Chest. 1990 Jun;97(6):1420-5.doi:10.1378/chest.97.6.1420
  95. Cahan C, Decker MJ, Hoekje PL, Strohl KP.Agreement between noninvasive oximetric values for oxygen saturation. Chest. 1990 Apr;97(4):814-9.doi:10.1378/chest.97.4.814
  96. Bickler PE, Feiner JR, Severinghaus JW. Effects of skin pigmentation on pulse oximeter accuracy at low saturation. Anesthesiology. 2005 Apr;102(4):715-9.doi:10.1097/00000542-200504000-00004
  97. Feiner JR, Severinghaus JW, Bickler PE. Dark skin decreases the accuracy of pulse oximeters at low oxygen saturation: the effects of oximeter probe type and gender. Anesth Analg. 2007 Dec;105(6 Suppl):S18-23. doi:10.1213/01.ane.0000285988.35174.d9
  98. Sjoding MW, Dickson RP, Iwashyna TJ, et al. Racial Bias in Pulse Oximetry Measurement. N Engl J Med. 2020 Dec 17;383(25):2477-2478. doi:10.1056/NEJMc2029240
  99. Galván Casas C, Català A, Carretero Hernández G, et al. Classification of the cutaneous manifestations of COVID-19: a rapid prospective nationwide consensus study in Spain with 375 cases. Br J Dermatol. 2020 Jul;183(1):71-77.doi:10.1111/bjd.19163
  100. Fahmy DH, El-Amawy HS, El-Samongy MA, et al. COVID-19 and dermatology: a comprehensive guide for dermatologists. J Eur Acad Dermatol Venereol. 2020 Jul;34(7):1388-1394.doi:10.1111/jdv.16545
  101. Freeman EE, McMahon DE, Lipoff JB, et al. Pernio-like skin lesions associated with COVID-19: A case series of 318 patients from 8 countries. J Am Acad Dermatol. 2020;83(2):486-492.doi:10.1016/j.jaad.2020.05.109
  102. Suchonwanit P, Leerunyakul K, Kositkuljorn C. Cutaneous manifestations in COVID-19: Lessons learned from current evidence. J Am Acad Dermatol. 2020;83(1):e57-e60.doi:10.1016/j.jaad.2020.04.094
  103. De Giorgi V, Recalcati S, Jia Z, et al. Cutaneous manifestations related to coronavirus disease 2019 (COVID-19): A prospective study from China and Italy. J Am Acad Dermatol. 2020;83(2):674-675. doi:10.1016/j.jaad.2020.05.073
  104. Jia JL, Kamceva M, Rao SA, Linos E. Cutaneous manifestations of COVID-19: A preliminary review. J Am Acad Dermatol. 2020 Aug;83(2):687-690.doi:10.1016/j.jaad.2020.05.059
  105. Recalcati S. Cutaneous manifestations in COVID-19: a first perspective. J Eur Acad Dermatol Venereol. 2020 May;34(5):e212-e213.doi:10.1111/jdv.16387
  106. Daneshgaran G, Dubin DP, Gould DJ. Cutaneous Manifestations of COVID-19: An Evidence-Based Review. Am J Clin Dermatol. 2020;21(5):627-639. doi:10.1007/s40257-020-00558-4.doi:10.1007/s40257-020-00558-4
  107. de Masson A, Bouaziz JD, Sulimovic L, et al. Chilblains is a common cutaneous finding during the COVID-19 pandemic: A retrospective nationwide study from France. J Am Acad Dermatol. 2020;83(2):667-670.doi:10.1016/j.jaad.2020.04.161
  108. Sachdeva M, Gianotti R, Shah M, et al. Cutaneous manifestations of COVID-19: Report of three cases and a review of literature. J Dermatol Sci. 2020;98(2):75-81.doi:10.1016/j.jdermsci.2020.04.011
  109. Freeman EE, McMahon DE, Lipoff JB, et al. The spectrum of COVID-19-associated dermatologic manifestations: An international registry of 716 patients from 31 countries. J Am Acad Dermatol. 2020 Oct;83(4):1118-1129.doi:10.1016/j.jaad.2020.06.1016
  110. Türsen Ü, Türsen B, Lotti T. Cutaneous sıde-effects of the potential COVID-19 drugs. Dermatol Ther. 2020 Jul;33(4):e13476. doi: 10.1111/dth.13476. Epub 2020 May 22.doi:10.1111/dth.13476
  111. Avanzato AA, Matson MJ, Seifert SN, et al. Case Study: Prolonged Infectious SARS-CoV-2 Shedding from an Asymptomatic Immunocompromised Individual with Cancer. Cell 2020 December 23;183(1–12).doi:10.1016/j.cell.2020.10.049
  112. Aydillo T, Gonzalez-Reiche AS, Aslam S, et al. Shedding of Viable SARS-CoV-2 after Immunosuppressive Therapy for Cancer. N Engl J Med. 2020 Dec 24;383(26):2586-2588.doi:10.1056/NEJMc2031670
  113. Baang JH, Smith C, Mirabelli C, et al. Prolonged Severe Acute Respiratory Syndrome Coronavirus 2 Replication in an Immunocompromised Patient. J Infect Dis. 2021 Jan 4;223(1):23-27. doi:10.1093/infdis/jiaa666
  114. Choi B, Choudhary MC, Regan J, et al. Persistence and Evolution of SARS-CoV-2 in an Immunocompromised Host. N Engl J Med. 2020 Dec 3;383(23):2291-2293.doi:10.1056/NEJMc2031364
  115. Tarhini H, Recoing A, Bridier-Nahmias A, et al. Long term SARS-CoV-2 infectiousness among three immunocompromised patients: from prolonged viral shedding to SARS-CoV-2 superinfection. J Infect Dis. 2021 Feb 8:jiab075. doi: 10.1093/infdis/jiab075. Online ahead of print.
  116. Nonaka CKV, Franco MM, Graf T, et al. Genomic evidence of a SARS-CoV-2 reinfection case with E484K spike mutation in Brazil. Preprints 2021, 2021010132. doi: 10.20944/preprints202101.0132.v1
  117. Naveca F, da Costa C, Nascimento V, et al. SARS-CoV-2 reinfection by the new Variant of Concern (VOC) P.1 in Amazonas, Brazil. Preprint. Published 2021 January 18.
  118. Resende PC, Bezerra JF, de Vasconcelos RHT, et al. Spike E484K mutation in the first reinfection case confirmed in Brazil, 2020. Preprint. Published 2021 January 10, 2021.
  119. Harrington D, Kele B, Pereira S, et al. Confirmed Reinfection with SARS-CoV-2 Variant VOC-202012/01. Clin Infect Dis. 2021 Jan 9:ciab014. doi: 10.1093/cid/ciab014. Online ahead of print.
  120. Zucman N, Uhel F, Descamps D, Roux D, Ricard JD. Severe reinfection with South African SARS-CoV-2 variant 501Y.V2: A case report.  Clin Infect Dis. 2021 Feb 10:ciab129. doi: 10.1093/cid/ciab129. Online ahead of print.
  121. Wibmer CK, Ayres F, Hermanus T, et al. SARS-CoV-2 501Y.V2 escapes neutralization by South African COVID-19 donor plasma. Preprint. bioRxiv. 2021;2021.01.18.427166. Published 2021 January 19. doi: 10.1101/2021.01.18.427166