Pathophysiology, Transmission, Diagnosis, and Treatment of Coronavirus Disease 2019 (COVID-19): A Review
Main result
Transmission of SARS-CoV-2 is usually by droplets when in close face-to-face contact.
The infection can have symptomatic, asymptomatic and pre-symptomatic carriers. The time it takes for the onset of symptoms is approximately 5 days, with 97.5% of people developping symptoms in an average of 11.5 days.
The most common symptoms are fever, dry cough, and dyspnea.
Observed radiographic and biological abnormalities such as lymphopenia and elevated LDH are common but non-specific.
Diagnosis includes the detection of SARS-CoV-2 by an rt-PCR test. False negatives can occur in 20-67% of cases depending on the quality of the tests.
Manifestations of COVID-19 range from asymptomatic carriers to the fulminant form of the pathology, which is characterized by sepsis and respiratory failure. Approximately 5% of patients with COVID-19, and 20% of hospitalized patients, have severe symptoms requiring intensive care support. More than 75% of hospitalized patients require oxygen therapy.
Dexamethasone reduces mortality at 28 days in patients requiring oxygen supplementation with standard care (21.6% vs. 24.6%; age-adjusted rate ratio 0.83 [95% CI,0.74-0.92]) and remdesivir improves remission time from 15 to 11 days.
In a randomized trial of 103 patients, convalescent plasma did not decrease remission time.
Reported data from the United States show that the mortality rate of COVID-19 varies with age and is 0.3 per 1000 cases among young patients aged 5 to 17 years. This mortality rate increases to 304.9 per 1000 cases for patients aged 85 years or older. The mortality rate for patients admitted to intensive care units is estimated to be 40%.
120 vaccines targeting SARS-CoV-2 are in development. Until then, methods to reduce the spread of the virus still include social distancing, wearing a mask when social distancing is no longer respected, and "contact tracing".
Takeaways
General updating of knowledge (research stopped on 15 June 2020).
Since 1 July 2020, more than 10 million people have been infected worldwide with COVID-19.
No vaccine or treatment is officially declared.
There are still a certain number of imprecisions concerning the transmission of the virus (weak transmission from mother to fetus in the 3rd trimester of pregnancy), its global mechanism of action and the treatments to be considered according to the gradation of the stages of the pathology.
However, certain points still need to be examined in greater detail:
- The question of the length of hospitalisation is crucial, especially in patients suffering from non-serious or even non-complicated forms of the disease.
- The question of acquired immunity in terms of the proportion of neutralising and/or "non-neutralising" antibody titers which would not be sufficient to protect against reinfection or even co-infection with COVID-19.
- The search for significant and specific markers for the diagnosis and prognosis of COVID-19.
- The use of broad-spectrum antibiotics should be reserved for cases presenting radiological abnormalities and/or inflammatory markers compatible with a declared co-infection or for immunocompromised and/or severe patients.
- The aftereffects of severe sepsis-like forms of COVID-19 should be monitored as they may increase the overall frailty of patients.
Strength of evidence Weak
Review based on studies pre-selected by clinicians without specifying grade, quality criteria, inclusion or exclusion criteria, all of which are based on bibliographical research.
Databases of recent pre-prints (not peer-reviewed and subject to change).
Objectives
Bibliographic review of knowledge on the known coronaviruses SARS-CoV-2, SARS-CoV, and MERS-CoV.
Method
Indexed databases (general and recent): PubMed, LitCovid, and MedRxiv.
Referenced sites: ClinicalTrials.gov, Chinese Clinical Trial Registry, and The International Clinical Trials Registry.
Evidence-based guidelines for treatments with data from the National Health Institutes.
bibliovid.org and its content are bibliovid property.