Year : 2020 | Volume
: 5 | Issue : 1 | Page : 22--26
A review of novel coronavirus infection (Coronavirus Disease-19)
Neelesh Jain, Animesh Choudhury, Jayesh Sharma, Venkata Kumar, Divyendu De, Richa Tiwari
Balco Medical Centre, A Unit of Vedanta Medical Research Foundation, Raipur, Chhattisgarh, India
Balco Medical Centre, A Unit of Vedanta Medical Research Foundation, Raipur, Chhattisgarh
Coronavirus (CoV) disease-2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome-CoV-2. The disease started in 2019 in Wuhan, China, and has spread globally, resulting in a pandemic. Common symptoms include fever, cough, and shortness of breath. Muscle pain, sputum production, and sore throat are less common symptoms. While the majority of cases result in mild symptoms, some progress to pneumonia and multiorgan failure. The deaths per number of diagnosed cases is estimated at between 1% and 5%, but varies by age and other health conditions. The infection is spread from one person to others via respiratory droplets, often produced during coughing and sneezing. It takes 2–14 days to develop symptoms from the day of exposure. Reverse transcription-polymerase chain reaction from a nasopharyngeal swab or oropharyngeal swab is the standard method of diagnosis. The infection can also be diagnosed from a combination of symptoms, risk factors, and a chest computed tomography scan showing features of pneumonia. Measures recommended to prevent the disease include frequent hand washing, maintaining distance from other people, and not touching one's face. The use of masks is recommended for those who are suspected to have the virus and to their caregivers, but not the general public. As of now, there is no vaccine or specific antiviral treatment for COVID-19; management involves treatment of symptoms, supportive care, and experimental measures. The World Health Organization declared the 2019–2020 CoV outbreak a pandemic and a Public Health Emergency of International Concern.
|How to cite this article:|
Jain N, Choudhury A, Sharma J, Kumar V, De D, Tiwari R. A review of novel coronavirus infection (Coronavirus Disease-19).Glob J Transfus Med 2020;5:22-26
|How to cite this URL:|
Jain N, Choudhury A, Sharma J, Kumar V, De D, Tiwari R. A review of novel coronavirus infection (Coronavirus Disease-19). Glob J Transfus Med [serial online] 2020 [cited 2021 Apr 13 ];5:22-26
Available from: https://www.gjtmonline.com/text.asp?2020/5/1/22/282732
Coronaviruses (CoVs) are enveloped, positive-sense, single-stranded RNA viruses ranging from 60 to 140 nm in diameter with spike-like projections on its surface, giving it a crown-like appearance under the electron microscope, hence the name CoV. Four CoVs namely HKU1, NL63, 229E, and OC43 have been in circulation in humans, and generally cause mild respiratory disease. On December 31, 2019, a cluster of cases of “pneumonia of unknown origin” in people associated with the Huanan Seafood Wholesale Market has been reported in Hubei province, China. Only a few days later, Chinese health authorities confirmed that this cluster was associated with a novel CoV and was named CoV disease-19 (COVID-19) by the World Health Organization (WHO). COVID-19 is closely associated with bat-derived severe acute respiratory syndrome (SARS-CoV)-like CoV (bat-SL-covzc45 and bat-SL-covzxc21) (with 88% identity), but is far away from SARS-CoV (about 79%) and MERS-CoV (about 50%). By the end of March 2020, a little less than 900,000 cases of COVID-19 and approximately 42,000 deaths have been reported globally. India has reported around 1400 cases with 35 mortality till March 31, 2020. This article gives an overview about this new virus. As knowledge about this virus is rapidly evolving, readers are requested to update themselves regularly.
The study objective was to review available information regarding COVID 19 virus, its origin, epidemiology, pathophysiology, diagnosis, available treatment options, prognosis of disease, and challenges posed by the pandemic.
Methodology of review
The study methodology was review of available information in Google and PUBMED.
In the past two decades, there have been two events wherein crossover of animal beta CoVs to humans has resulted in severe disease. The first such instance was in 2002–2003 when a new CoV of the β genera and with origin in bats crossed over to humans via the intermediary host of palm civet cats in the Guangdong province of China. This virus, designated as SARS-CoV, affected 8422 people mostly in China and Hong Kong and caused 916 deaths (mortality rate 11%) before being contained. In 2012, the Middle East respiratory syndrome-CoV (MERS-CoV), also of bat origin, emerged in Saudi Arabia with dromedary camels as the intermediate host and affected 2494 people and caused 858 deaths (fatality rate 34%).
Epidemiology of Coronavirus Disease-19
A cluster of pneumonia cases of unknown origin in Hubei province, China, caused concern among health officials in late December 2019. On December 31, an alert was issued by the Wuhan Municipal Health Commission, a rapid response team was sent to Wuhan by the Chinese Center for Disease Control and Prevention (China CDC), and a notification was made to the WHO. Likely potential causes including influenza, avian influenza, adenovirus, SARS-CoV, and MERS-CoV were ruled out. Epidemiological investigation implicated Wuhan's Huanan Seafood Wholesale Market, which was shut down and disinfected, and active case finding was initiated and vigorously pursued. On January 7, 2020, the causative pathogen was identified as a novel CoV, and genomic characterization and test method development ensued. Now named 2019-nCoV, the virus is distinct from both SARS-CoV and MERS-CoV, yet closely related. Early cases suggested that COVID-19 (i.e., the new name for disease caused by the novel CoV) may be less severe than SARS and MERS. However, illness onset among rapidly increasing numbers of people and mounting evidence of human-to-human transmission suggests that 2019-nCoV is more contagious than both SARS-CoV and MERS-CoV., The first fatal case was reported on January 11, 2020. The massive migration of Chinese during the Chinese New Year fueled the epidemic. Cases in other provinces of China and those in other countries (Thailand, Japan, and South Korea in quick succession) were reported in people who were returning from Wuhan. Transmission to health-care workers caring for patients was described on January 20, 2020. By January 23, 11 million population of Wuhan was placed under lockdown with restrictions of entry and exit from the region. Soon, this lockdown was extended to other cities of Hubei province. Cases of COVID-19 in countries outside China were reported in those with no history of travel to China, suggesting that local human-to-human transmission was occurring in these countries., Airports in different countries including India put in screening mechanisms to detect symptomatic people returning from China and placed them in isolation and testing them for COVID-19. Soon, it was apparent that the infection could be transmitted from asymptomatic people and also before the onset of symptoms. Therefore, countries including India who evacuated their citizens from Wuhan through special flights or had travelers returning from China, placed all people symptomatic or otherwise in isolation for 14 days and tested them for the virus. Cases continued to increase exponentially, and modeling studies reported an epidemic doubling time of 1.8 days. As of March 22, 2020, around 300,000 cases of COVID-19 and approximately 13,000 deaths have been reported globally. India has reported around 394 cases with 7 mortalities till date. Many of the contacts of these cases have been quarantined. These numbers are possibly an underestimate of the infected and dead due to the limitations of surveillance and testing. Though the SARS-CoV-2 originated from bats, the intermediary animal through which it crossed over to humans is uncertain.,
Pathogenesis and Clinical Features of Coronavirus Disease-19
All ages are susceptible. Infection is transmitted through large droplets generated during coughing and sneezing by symptomatic patients, but can also occur from asymptomatic people and before the onset of symptoms. Studies have shown higher viral loads in the nasal cavity as compared to the throat, with no difference in viral burden between symptomatic and asymptomatic people. Patients can be infectious for as long as the symptoms last and even on clinical recovery. These infected droplets can spread 1–2 m and deposit on surfaces. The virus can remain viable on surfaces for days in favorable atmospheric conditions, but are destroyed in less than a minute by common disinfectants such as sodium hypochlorite and hydrogen peroxide. Infection is acquired either by inhalation of these droplets or touching surfaces contaminated by them or then touching the nose, mouth, and eyes. The virus is also present in the stool, and contamination of the water supply and subsequent transmission via aerosolization/feco–oral route is also hypothesized. The incubation period varies from 2 to 14 days (median 5–7 days). Studies have identified angiotensin receptor 2 as the receptor through which the virus enters the respiratory mucosa. The basic case reproduction rate is estimated to range from 2 to 6.47 in various modeling studies., The clinical features of COVID-19 are varied, ranging from asymptomatic state to acute respiratory distress syndrome (ARDS) and multiorgan dysfunction. Fever, cough, sore throat, headache, fatigue, headache, myalgia, and breathlessness are the common clinical features of COVID-19. Conjunctivitis has also been described. In a subset of patients, by the end of the 1st week, the disease can progress to pneumonia, respiratory failure, and death. This progression is associated with extreme rise in inflammatory cytokines including interleukin (IL) IL-2, IL-7, IL-10, GCSF, IP10, MCP1, MIP1A, and tumor necrosis factor-alpha.
The median time from the onset of symptoms to develop dyspnea was 5 days, hospitalization was 7 days, and ARDS was 8 days. The need for intensive care admission was in 15%–25% of the affected patients in the published literature. Complications included acute lung injury, ARDS, shock, and acute kidney injury. Recovery started in the 2nd or 3rd week. The median duration of hospital stay in those who recovered was 10 days. Adverse outcomes and death are more common in the elderly and those with underlying comorbidities (50%–75% of fatal cases). Fatality rate in hospitalized adult patients ranged from 4% to 11%. The overall case fatality rate is estimated to range between 2% and 3%.
A suspect case is defined as one with fever, sore throat, cough, and difficulty in breathing, who has a history of travel to China or other areas of persistent local transmission or contact with patients with similar travel history or those with confirmed COVID-19 infection. However, cases may be asymptomatic or even without fever. A confirmed case is a suspect case with a positive molecular test. Specific diagnosis is by specific molecular tests on respiratory samples (oropharyngeal swab/nasopharyngeal swab/sputum/endotracheal aspirates and bronchoalveolar lavage). Virus may also be detected in the stool and in severe cases, the blood. In a suspect case in India, the appropriate sample has to be sent to designated reference labs earmarked by the Government of India or the National Institute of Virology in Pune. The white cell count is usually low. There may be lymphopenia; a lymphocyte count <1000 has been associated with severe disease. The platelet count is usually normal or mildly low. The C-reactive protein and erythrocyte sedimentation rate are generally elevated, but procalcitonin levels are usually normal. A high procalcitonin level may indicate a bacterial co-infection. The alanine aminotransferase/aspartate aminotransferase, prothrombin time, creatinine, D-dimer, creatine phosphokinase, and lactic acid dehydrogenase may be elevated, and high levels are associated with severe disease. The chest X-ray usually shows bilateral infiltrates, but may be normal in early disease. Computed tomography (CT) is more sensitive and specific. CT imaging generally shows infiltrates, ground glass opacities, and subsegmental consolidation. It is also abnormal in asymptomatic patients/patients with no clinical evidence of lower respiratory tract involvement. In fact, abnormal CT scans have been used to diagnose COVID-19 in suspect cases with negative molecular diagnosis; many of these patients had positive molecular tests on repeat testing., Although the virus (SARS-Cov-2) nucleic acid reverse transcription-polymerase chain reaction (PCR) test has become the standard method for the diagnosis of SARS-CoV-2 infection, these real-time PCR test kits have many limitations including accessibility and availability issues. There are various serological tests based on immunoglobulin M (IgM)/IgG antibody detection, suitable for the qualitative detection of CoV (SARS-CoV-2/COVID-19) These include ELISA tests, rapid Chromatographic tests and others. IgM antibody generally begins to rise within 1 week of initial infection. IgG appears about 14 days after infection. Validation process is under way in China, Europe, and the USA. The results have been very promising with the advantages of rapid results, accuracy (high sensitivity [~89%] and specificity [~93%]), low cost, ease of use, easy accessibility, fast screening of COVID-19 infections, etc.
All types of respiratory viral infections (influenza, parainfluenza, respiratory syncytial virus, adenovirus, human metapneumovirus, and non-COVID-19 CoV), atypical organisms (mycoplasma and chlamydia), and bacterial infections have been included in the differential diagnosis of COVID-19. It is not possible to differentiate COVID-19 from these infections clinically or through routine laboratory tests. Therefore, travel history becomes important.
Till date, no confirmed or approved treatment and vaccination is available and hence the treatment is essentially supportive and symptomatic. The first step is to ensure adequate isolation to prevent transmission to other contacts, patients, and health-care workers. Mild illness should be managed at home with counseling about danger signs. The usual principles are maintaining hydration and nutrition and controlling fever and cough. In hypoxic patients, provision of oxygen through nasal prongs, face mask, high-flow nasal cannula, or noninvasive ventilation is indicated. Mechanical ventilation and even extracorporeal membrane oxygen support may be needed. Renal replacement therapy may be needed in some cases. Antibiotics and antifungals are required if co-infections are suspected or proven. Multiple trials are ongoing on the use of various drugs including hydroxychloroquine, oseltamivir, ritonavir, and lopinavir. Detailed guidelines for critical care management for COVID-19 have been published by the WHO.,,
In the case series of 99 hospitalized patients with COVID-19 infection from Wuhan, oxygen was given to 76%, noninvasive ventilation in 13%, mechanical ventilation in 4%, extracorporeal membrane oxygenation in 3%, continuous renal replacement therapy in 9%, antibiotics in 71%, antifungals in 15%, glucocorticoids in 19%, and intravenous immunoglobulin therapy in 27%. Antiviral therapy consisting of oseltamivir, ganciclovir, lopinavir, and ritonavir was given to 75% of the patients. The duration of noninvasive ventilation was 4–22 days (median 9 days) and mechanical ventilation for 3–20 days (median 17 days). In the case series of children discussed earlier, all children recovered with basic treatment and did not need intensive care. There is anecdotal experience with the use of remdesvir, a broad-spectrum anti-RNA drug developed for Ebola in the management of COVID-19. More evidence is needed before these drugs are recommended. Other drugs proposed for therapy are arbidol (an antiviral drug available in Russia and China), intravenous immunoglobulin, interferons, chloroquine, and plasma of patients recovered from COVID-19.
As of now, no approved treatments are available for this infection, hence prevention is crucial. Several properties of this virus make prevention difficult such as non-specific features of the disease, the infectivity even before the onset of symptoms in the incubation period, transmission from asymptomatic people, long incubation period, tropism for mucosal surfaces such as the conjunctiva, prolonged duration of the illness, and transmission even after clinical recovery. Isolation of confirmed or suspected cases with mild illness at home is recommended. The ventilation at home should be good with sunlight to allow for the destruction of virus. Patients should be asked to wear a simple surgical mask and practice cough hygiene. Caregivers should be asked to wear a surgical mask when in the same room with the patient and use frequent hand hygiene. The greatest risk in COVID-19 is transmission to the health-care workers involved in the care of COVID-19 patients, and those who are elderly and/or with the underlying health conditions (e.g., hypertension, diabetes, cardiovascular disease, chronic respiratory disease, and cancer) are considered to be more at risk of developing the severe symptoms of COVID-19. In the SARS outbreak of 2002, 21% of those affected were health-care workers., It is important to protect health-care workers to ensure continuity of care and to prevent transmission of infection to other patients. While COVID-19 transmits as a droplet pathogen and is placed in Category B of infectious agents (highly pathogenic H5N1 and SARS), by the China National Health Commission, infection control measures recommended are those for Category A agents (cholera and plague). Patients should be placed in separate rooms or cohorted together. The rooms, surfaces, and equipment should undergo regular decontamination, preferably with sodium hypochlorite. Health-care workers should be provided with fit tested N95 respirators and protective suits and goggles. Airborne transmission precautions should be taken during aerosol-generating procedures such as intubation, suction, and tracheostomies. All contacts including health-care workers should be monitored for the development of symptoms of COVID-19. Patients can be discharged from isolation once they are afebrile for at least 3 days and have two consecutive negative molecular tests at 1-day sampling interval. Negative molecular tests are not a prerequisite for discharge. At the community level, people should be asked to avoid crowded areas and postpone nonessential travel to places with ongoing transmission. They should be asked to practice cough hygiene by coughing in sleeve/tissue rather than hands and practice hand hygiene frequently. Patients with respiratory symptoms should be asked to use surgical masks. The use of mask by healthy people in public places has not shown to protect against respiratory viral infections and is currently not recommended by the WHO. The international response has been dramatic. Initially, there were massive travel restrictions to China, and people returning from China/evacuated from China are being evaluated for clinical symptoms, isolated, and tested for COVID-19 for 2 weeks even if asymptomatic. However, now with the rapid worldwide spread of the virus, these travel restrictions have extended to other countries. Whether these efforts will lead to slowing of the viral spread is not known. A vaccine is under development.
Crowdsourced epidemiological data can be useful to monitor emerging outbreaks, such as COVID-19. This is an early report of a rapidly evolving situation, and the parameters discussed here could change quickly. In the coming weeks, we will continue to monitor the epidemiology of this outbreak using data from news reports and official sources. This new virus pandemic has challenged the economic, medical, and public health infrastructure of the world.
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Conflicts of interest
There are no conflicts of interest.
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