Review of Burden, Clinical Definitions, and Management of COVID-19 Cases

Abstract

Our understanding of SARS-CoV-2, the virus responsible for coronavirus disease 2019 (COVID-19), its clinical manifestations, and treatment options continues to evolve at an unparalleled pace. This review sought to summarize the key literature regarding transmission, case definitions, clinical management, and the burden of COVID-19. Our review of the literature showed that SARS-CoV-2 was mainly transmitted via inhalation of respiratory droplets containing the virus and had a mean incubation period of 4-6 days. The commonly reported symptoms were fever (75.3% ± 18.7%) and cough (62.6% ± 17.7%) across the spectrum of clinical disease-mild, moderate, severe, and critical, but with the disease phenotype varying with severity. Categorization of these cases for home care or hospital management needs to be defined, with risk stratification accounting for the age of the patient and the presence of underlying comorbidities. The case definitions varied among countries, which could have contributed to the differences in the case fatality rates among affected countries. The severity and risk of death due to COVID-19 was associated with age and underlying comorbidities. Asymptomatic cases, which constitute 40-80% of COVID-19 cases are a considerable threat to control efforts. The presence of fever and cough may be sufficient to warrant COVID-19 testing, but using these symptoms in isolation will miss a proportion of cases. A clear definition of a COVID-19 case is essential for the management, treatment, and tracking of clinical illness, and to inform the quarantine measures and social distancing that can help control the spread of SARS-CoV-2.

Figure 1.

Identification and management of COVID-19 cases. Monitoring for suspected cases of COVID-19 is crucial to halt the transmission of SARS-CoV-2. Suspected cases who have had contact with an infected person (asymptomatic/symptomatic) need to be isolated and screened for SARS-CoV-2 using sensitive nucleic acid amplification tests (NAATs). It is recommended that infected individuals who are asymptomatic self-isolate and be monitored at home. Individuals who progress to develop clinical disease can be triaged into mild/moderate and severe/critical case for clinical management/treatment. However, the presence of comorbidities and the age of the patient can be used to triage patients for hospitalization or home care. Once recovered, patients should be monitored because they could still be infectious.

Figure 2.

Commonly reported clinical symptoms of COVID-19. Data were obtained from 21 studies involving COVID-19 patients including children and adults. For the pooled analysis, the mean percentage of patients who developed a particular symptom was plotted with the upper standard error. Fever and cough were the commonly reported symptoms. Data were obtained from published data.^{,,,,,,,–,,,,–}