SARS-CoV-2: Difference between revisions
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*Non-test based (preferred) |
*Non-test based (preferred) |
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**Asymptomatic: isolate for 10 days from swab |
**Asymptomatic: isolate for 10 days from swab |
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**Mild to moderate symptoms in immunocompetent person: 10 days from onset of symptoms, as long as afebrile and clinically improving |
**Mild to moderate symptoms in immunocompetent person: 10 days from onset of symptoms, as long as afebrile (without antipyretics) and clinically improving |
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**Severe (i.e. ICU-level care) or immunocompromised: 20 days from onset of symptoms, as long as afebrile and clinically improving |
**Severe (i.e. ICU-level care) or immunocompromised: 20 days from onset of symptoms, as long as afebrile (without antipyretics) and clinically improving |
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***Immunocompromise includes chemotherapy, untreated [[HIV]] with CD4 <200, [[primary immunodeficiency]], [[prednisone]] 20 mg/day for 14 days, and other immunosuppressing medication |
***Immunocompromise includes [[chemotherapy]], untreated [[HIV]] with CD4 <200, [[primary immunodeficiency]], [[prednisone]] 20 mg/day for 14 days, and other immunosuppressing medication |
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*Test based (alternative): 2 negative swabs at least 24 hours apart (if still positive, repeat in 3 to 4 days), as long as afebrile and clinically improving |
*Test based (alternative): 2 negative swabs at least 24 hours apart (if still positive, repeat in 3 to 4 days), as long as afebrile and clinically improving |
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Revision as of 14:11, 22 February 2021
Background
Microbiology
- Coronavirus related to SARS-CoV
- Virion consists of:
- Spike glycoprotein (S), which appears to be an important virulence factor
- Vaccines may target either the full protein or only its distal receptor binding domain
- Membrane protein (M)
- Nucleocapsid protein (N)
- Hemagglutinin esterase (He)
- Envelope protein (E)
- Spike glycoprotein (S), which appears to be an important virulence factor
Epidemiology
- Transmitted mostly by respiratory droplets, with some amount transmission via aerosols and little to no transmission via contact
- First cases detected Dec 2019 related to likely exposure in wet market in Wuhan, Hubei, China, and declared a pandemic in 2020
- Secondary household attack rate of 12-17%
Risk Factors for Mortality
- Greater age
- Male sex
- COPD
- Dyslipidemia
- Diabetes
Clinical Manifestations
- Incubation period 4 to 5 days (range 2 to 11 days), possibly as long as 14 days in some cases
- Main presenting symptoms were fever and cough, followed by myalgia, fatigue, headache, dyspnea
- Other symptoms include dyspnea, rhinorrhea, vomiting, diarrhea, anosmia/hyposmia
- Lymphopenia is common, as is hypoalbuminemia, elevated D-dimer, CRP, LDH, AST/ALT
- Viral load detectable before symptom onset and peaks around the time of symptom onset
Pregnancy
- Please refer to a living systematic review on the topic
- Slightly less reported fever and myalgias
- Slightly more ICU admissions and mechanical ventilation
- Risk factors included age, obesity, hypertension, and diabetes
- With regards to the fetus, there were more preterm deliveries (6%) and more needed NICU admission (25%)
Severity
- Mild: no oxygen
- Moderate: supplemental oxygen
- Severe: non-invasive mechanical ventilation
- Critical: invasive mechanical ventilation
Complications
- In critically ill patients:
- ARDS (75%)
- AKI (40%)
- Thrombosis (10%)
Diagnosis
- PCR from NP swab
- Highest sensitivity within 5 days of symptom onset, with decreasing sensitivity as the disease enters the immune-mediated phase
- May be positive long after no longer infectious
- Diagnostic accuracy of PCR by sample site (below) has a lot of heterogeneity among the studies
| Sensitivity | Specificity | |
|---|---|---|
| Upper Respiratory Samples | ||
| Oral | 56 | 99 |
| Nasal | 76 | 100 |
| NP | 97 | 100 |
| Nasal | 95 | 100 |
| Saliva | 85 | 100 |
| Mid-turbinate | 100 | 100 |
| Upper Versus Lower Tract | ||
| Upper respiratory tract | 57 | 100 |
| Lower respiratory tract | 81 | 100 |
| Single Versus Repeat Testing | ||
| Single test | 71 | 100 |
| Repeat testing | 100 | 100 |
- Serology (IgM and IgG)
- Total antibodies have poor sensitivity (51%) in first week, and increases to about 90% by week 3
Management
- For patients no requiring supplemental oxygen, the focus is on supportive care
- For patients requiring supplemental oxygen or with oxygen saturation less than 94%:
- Dexamethasone 6 mg PO/IV daily for 10 days, which has a mortality benefit
- Remdesivir 200 mg PO once on day one followed by 100 mg PO daily for 5-10 days, which has not been shown to have a mortality benefit
- Avoid hydroxychloroquine/chloroquine, lopinavir-ritonavir
- Tocilizumab may be indicated if progressing despite usual care, still requiring oxygen and CRP ≥75 mg/L, per RECOVERY trial
Anticoagulation
- A multiplatform RCT combined ATTACC, REMAP-CAP, and ACTIV-4a looked at therapeutic anticoagulation (compared to prophylactic)
- Therapeutic anticoagulation with heparin derivatives provided for up to 14 days
- Helpful in moderately ill patients, regardless of D-dimer value
- Potentially harmful in severely or critically ill patients
Prevention
Infection Prevention and Control
Healthcare Workers
- Awaiting results
- If symptomatic, HCWs should be off work
- If asymptomatic, HCWs may return to work while awaiting results, depending on the reason for testing and the staffing needs
- Positive but asymptomatic: in exceptional circumstances, may return to work early
Clearance
- Non-test based (preferred)
- Asymptomatic: isolate for 10 days from swab
- Mild to moderate symptoms in immunocompetent person: 10 days from onset of symptoms, as long as afebrile (without antipyretics) and clinically improving
- Severe (i.e. ICU-level care) or immunocompromised: 20 days from onset of symptoms, as long as afebrile (without antipyretics) and clinically improving
- Immunocompromise includes chemotherapy, untreated HIV with CD4 <200, primary immunodeficiency, prednisone 20 mg/day for 14 days, and other immunosuppressing medication
- Test based (alternative): 2 negative swabs at least 24 hours apart (if still positive, repeat in 3 to 4 days), as long as afebrile and clinically improving
Further Reading
- Pathophysiology, Transmission, Diagnosis, and Treatment of Coronavirus Disease 2019 (COVID-19): A Review. JAMA. doi: 10.1001/jama.2020.12839
- UHN-MSH Ontario Clinical Practice Guidelines
- PHAC Interim guidelines for the clinical management of patients with moderate to severe COVID-19
References
- ^ Louise Lansbury, Benjamin Lim, Vadsala Baskaran, Wei Shen Lim. Co-infections in people with COVID-19: a systematic review and meta-analysis. Journal of Infection. 2020;81(2):266-275. doi:10.1016/j.jinf.2020.05.046.
- ^ Scott Simpson, Fernando U. Kay, Suhny Abbara, Sanjeev Bhalla, Jonathan H. Chung, Michael Chung, Travis S. Henry, Jeffrey P. Kanne, Seth Kligerman, Jane P. Ko, Harold Litt. Radiological Society of North America Expert Consensus Document on Reporting Chest CT Findings Related to COVID-19: Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA. Radiology: Cardiothoracic Imaging. 2020;2(2):e200152. doi:10.1148/ryct.2020200152.
- ^ Robert L. Gottlieb, Carlos E. Vaca, Roger Paredes, Jorge Mera, Brandon J. Webb, Gilberto Perez, Godson Oguchi, Pablo Ryan, Bibi U. Nielsen, Michael Brown, Ausberto Hidalgo, Yessica Sachdeva, Shilpi Mittal, Olayemi Osiyemi, Jacek Skarbinski, Kavita Juneja, Robert H. Hyland, Anu Osinusi, Shuguang Chen, Gregory Camus, Mazin Abdelghany, Santosh Davies, Nicole Behenna-Renton, Frank Duff, Francisco M. Marty, Morgan J. Katz, Adit A. Ginde, Samuel M. Brown, Joshua T. Schiffer, Joshua A. Hill. Early Remdesivir to Prevent Progression to Severe Covid-19 in Outpatients. New England Journal of Medicine. 2021. doi:10.1056/nejmoa2116846.
