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Year : 2020  |  Volume : 34  |  Issue : 1  |  Page : 1-4

COVID-19: A global crisis

1 Consultant Chest Physician, Mumbai, Maharashtra, India
2 Department of TB and Respiratory Diseases, Sharda University, Noida, Uttar Pradesh, India

Date of Submission18-Apr-2020
Date of Acceptance27-Apr-2020
Date of Web Publication6-Jul-2020

Correspondence Address:
S N Gaur
Department of TB and Respiratory Diseases, Sharda University, Noida, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijaai.ijaai_16_20

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How to cite this article:
Sarangdhar N, Gaur S N. COVID-19: A global crisis. Indian J Allergy Asthma Immunol 2020;34:1-4

How to cite this URL:
Sarangdhar N, Gaur S N. COVID-19: A global crisis. Indian J Allergy Asthma Immunol [serial online] 2020 [cited 2023 Mar 29];34:1-4. Available from: https://www.ijaai.in/text.asp?2020/34/1/1/289059

  Introduction Top

In December 2019, there was an epidemic of infection caused by a new (novel) strain of coronavirus (CoV) originating from the city of Wuhan in Hubei province of China that progressed to a pandemic spreading rapidly to several countries of the world. This disease, named as Coronavirus Disease-2019 (COVID-19) by the World Health Organization (WHO), continues to ravage the world, apart from high mortality and a devastating health impact, it has also disrupted global trade and supply chains with far reaching economic and political repercussions.

  Origin Top

Respiratory samples from a cluster of patients of pneumonia of unknown origin in Wuhan in December 2019 revealed a CoV, which on gene sequencing and phylogenetic analysis was found to share structural and genetic similarity with previous CoVs causing Severe Acute Respiratory Syndrome (SARS-CoV) and Middle East Respiratory Syndrome (MERS-CoV). Since this virus shared greater nucleotide identity with SARS-CoV, it was given the nomenclature of SARS-CoV-2 by the international committee on the taxonomy of viruses. SARS-CoV-2 is the seventh CoV identified to cause human disease after OC43, 229E, NL63, and HKU1 (causing mild illness) and SARS and MERS (causing severe illness).[1]

  Viral Structure, Pathogenesis, and Transmission Dynamics Top

CoVs are zoonotic pathogens and spread from animals to humans. SARS-CoV-2 is an encapsulated single-stranded, positive-sense RNA virus belonging to subgenus Sarbecovirus of the genus Betacoronavirus of the family Coronaviridae. The genome of SARS-CoV-2 is phylogenetically closest to a bat SARS-like CoV genome, indicating a probable bat origin.[2] It contains nucleocapsid (N) protein bound to the RNA genome, membrane (M) protein that determines the shape of the viral envelope, envelope (E) protein that interacts with M protein to form viral envelope and Spike (S) protein, which facilitates viral binding with host cell receptors [Figure 1]. On entry, SARS-CoV-2 binds to the angiotensin-converting enzyme 2 receptor present in the epithelial cells of the respiratory tract and also in renal tubules, intestinal lining and neurons, affecting mainly the respiratory system with the capacity to invade other organs as well. Viral replication and spread lead to several cytopathic effects that trigger the host immune response and cytokine storm, which if excessive can result in hypoxia, coagulation dysfunction, organ failure, and shock.
Figure 1: Structure of severe acute respiratory syndrome coronaviruses-2[3]

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A large number of patients identified from the cluster of the outbreak were traced to have visited the Huanan wholesale seafood market, which traded live exotic wild animals and seafood. A study of a familial cluster of cases from Shenzen city suggested the first possibility of human transmission. Person-to-person spread among close contacts (within a distance of 1-2 meters) from the index case through respiratory droplets generated due to coughing and sneezing is believed to be the major mode of transmission. Other routes of spread that have been postulated are through contact with oral, nasal and ocular mucous membranes, and from fomites. The incubation period is variable between 1 and 14 days, with a mean of 5 days as per the WHO and the Centre for Disease Control and Prevention. Disease severity is believed to be an important factor governing viral transmission. The reproductive number (Rº ), i.e., the number of people who can get infected from a case of COVID-19 is 2.2–2.68, implying that each case can infect ≥2 other persons.[4]

  Impact Top

Despite a much lower case fatality rate (CFR) (3%) than SARS (10%) and MERS (36%), COVID-19 has resulted in more deaths than both combined. The global outbreak of COVID-19 was declared a pandemic by WHO on March 11, 2020, with spread in 122 countries and territories involving 132,758 cases and causing around 4955 deaths. COVID-19 continued to spread rapidly, ravaging the world and a month later was found to have affected 213 countries and territories, infecting over 1.7 million people and causing over 1 lakh deaths worldwide, the largest number of cases located in the United States (5.2 lac), Spain (1.6 lac) Italy (1.5 lac), and Germany (1.2 lac), with India reporting over 10,000 cases and 300 deaths. As several countries closed national borders and imposed lockdowns with travel restrictions to contain viral spread, more than 3 billion people were made to stay and work from home and maintain social distancing, resulting in massive disruption of the international trade and global supply chains. Analysis by the United Nations department of economic and social affairs revealed that the global economy in 2020 could shrink by 1% due to COVID-19, a reversal from the forecast of 2.5% growth projected earlier.

  Clinical Features and Case Definitions Top

The incubation period varies between 1 to 14 days. According to the preliminary data, majority (81%) of patients had mild illness, whereas 14% and 5% were severe and critical, respectively. Patients aged ≥65 years and those with co-morbidities such as diabetes, hypertension, chronic respiratory or cardiovascular disease or immunosuppression are more susceptible. Common symptoms include fever and cough, dyspnea, sore throat, headache, and fatigue. Cold, diarrhea, hypogeusia, and hyposmia (decreased sensation of taste and smell, respectively) are less common.[5],[6] Since patients can have the symptoms of allergy and viral infection at the same time with considerable symptom overlap, it becomes important to differentiate [Table 1].
Table 1: Symptomatic differentiation of cold, influenza, and coronavirus disease-2019 (adapted from https://www.cdc.gov/flu/symptoms/coldflu.htm)

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The Government of India recently expanded the criteria for COVID-19 suspects to include:

  • All symptomatic individuals who have undertaken international travel in the past 14 days

  • OR

  • All symptomatic contacts of laboratory confirmed cases

  • OR

  • All symptomatic health-care personnel (HCP)

  • OR

  • All hospitalized patients with severe acute respiratory illness (fever and cough and/or shortness of breath)

  • OR

  • Asymptomatic direct and high risk contacts of a confirmed case (should be tested once between day 5 and day 14 after contact).[7]

Symptomatic refers to fever/cough/shortness of breath. Direct and high-risk contacts include those who live in the same household with a confirmed case and HCP who examined a confirmed case.

A confirmed case is defined as a person with laboratory confirmation of COVID-19 infection, irrespective of clinical signs and symptoms.[6]

Respiratory failure leading to acute respiratory distress syndrome (ARDS), acute cardiac and kidney injury, hepatic dysfunction, septic shock, and disseminated intravascular coagulation (DIC) are known complications. The CFR of COVID-19 varies from country to country, with an average of 3.06%.

  Diagnosis Top

CoV can be detected in respiratory samples (throat swab, bronchoalveolar lavage, sputum, or tracheal aspirate) during the early incubation period even before the symptom onset and persists for 7–12 days in moderate and up to 2 weeks in severe cases. Respiratory samples of all suspects are tested by real-time reverse transcriptase-polymerase chain reaction (rt RT-PCR) for the detection of SARS-CoV-2.[4] Serological tests are being evaluated and are currently pending approval. Imaging by chest radiographs or computerized tomography scans may reveal non-specific features of viral pneumonia, ground-glass opacities, fine reticular opacities, and infiltrates which are more often bilateral than unilateral and less commonly effusions or lymphadenopathy. Blood lymphocytopenia and eosinopenia are common.[5],[6]

  Treatment Top

In the absence of a novel specific anti-viral drug, treatment strategies are largely supportive. Patients with less severe infection may be considered for domiciliary management with advice for isolation and social distancing, with frequent monitoring. Supportive management includes analgesics, antipyretics, and empiric antibiotics, with more aggressive strategies such as fluid resuscitation, oxygen supplementation and mechanical ventilation, dialysis or renal replacement and others in patients who are critically ill. Corticosteroids are to be avoided unless they are indicated for another reason like exacerbation of asthma or chronic obstructive pulmonary disease. For patients with progressive deterioration of oxygenation indicators, rapid worsening on imaging and excessive activation of the body's inflammatory response, glucocorticosteroids may be used for a short period of time (3–5 days), with the dose not exceeding the equivalent of methylprednisolone 1–2 mg/kg/day. Based on the data from uncontrolled clinical trials, the combination of hydroxychloroquine (400 mg twice daily for 1 day followed by 200 mg twice daily for 4 days) in combination with azithromycin (500 mg once daily for 5 days) may be considered for off-label use in patients with severe disease and requiring intensive care medicine management, with monitoring for adverse effects including QTc interval.[6] For severe or critically ill pregnant women, pregnancy should preferably be terminated after consultation with obstetric, neonatal, and critical care specialists. In the midst of lockdown, patients of allergy may find it difficult to reach the allergy clinic; hence for them, it is advised to avoid any triggers that cause their symptoms to flare up and follow written action plans for allergy management.

Daily exposure to news about CoV may result in a range of responses and reactions can be emotional, somatic, or behavioral with the potential to negatively impact health and well-being. Patients, their relatives (mainly spouse and children), and close contacts often suffer from fear and anxiety and should be supported by counseling or strategies to deal with distress. It is important to avoid panic, follow all precautions, keep oneself well informed from authentic sources and be aware of any reactions (local or national) to the outbreak. Two consecutive respiratory samples for RT-PCR need to be negative to demonstrate clearing of infection.

  Infection Control and Prevention Top

All suspected cases should be traced, immediately provided with a surgical face mask and shifted to an isolation room maintaining adequate distance from others. Respiratory care givers and the contacts should take precautions with hand hygiene, cough etiquette, personal protective equipment (PPE), gloves, face masks (N-95), and eye goggles/shields need to be worn by health-care providers and also during invasive therapies and aerosol-generating procedures (intubation, cardiopulmonary resuscitation, bronchoscopy, and nebulization). Standard procedures for environmental cleaning, waste disposal, and disinfection of laundry and utensils should be followed. Standard recommendations to prevent the spread of COVID-19 include hand washing with alcohol-based hand rub or soap and water, covering the nose and mouth with a flexed elbow or disposable tissue when coughing and sneezing and avoiding close contact with anyone that has fever or cough. Social (or physical) distancing, defined as a set of non-pharmaceutical interventions or measures taken to prevent the spread of a contagious disease by maintaining a physical distance of more than 1 meter between people and using face mask whenever coming in contact of unknown person has gained importance as an infection control measure during the COVID-19 pandemic.

  Disposal of Dead Bodies Top

Disposal of dead bodies of COVID-19 patients should be done using all PPE and other precautionary measures strictly by the concerned staff and should be preferably done in electric crematorium. Dead body is not given to the family members/relatives to avoid spread of COVID-19 to them and to the community.

  References Top

Zhu N, Zhang D, Wang W, Li X, Yang B, Song J, et al. A novel coronavirus from patients with pneumonia in China, 2019. N Engl J Med 2020;382:727-33.  Back to cited text no. 1
Ren LL, Wang YM, Wu ZQ, Xiang ZC, Guo L, Xu T, et al. Identification of a novel coronavirus causing severe pneumonia in human: A descriptive study. Chin Med J (Engl) 2020. [Epub ahead of print].  Back to cited text no. 2
Seah I, Su X, Lingam G. Revisiting the dangers of the coronavirus in the ophthalmology practice. Eye (Lond) 2020. [Epub ahead of print].  Back to cited text no. 3
Guo Y, Cao Q, Hong Z, Tan Y, Chen S, Jin H, et al. The origin, transmission and clinical therapies on coronavirus disease 2019 (COVID-19) outbreak – An update on the status. Mil Med Res 2020;7:11.  Back to cited text no. 4
Zhang J, Dong X, Cao Y, Yuan Y, Yang Y, Yan Y, et al. Clinical characteristics of 140 patients infected with SARS-CoV-2 in Wuhan, China. Allergy 2020:1-12. [Epub ahead of print].  Back to cited text no. 5
Huang C, Wang Y, Li X, Ren L, Zhao J, Hu Y, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet 2020;395:497-506.  Back to cited text no. 6
Revised Guidelines on Clinical Management of COVID-19. Directorate General of Health Services (EMR Division). Revised National Clinical Management Guideline for COVID19 31032020.pdf. Ministry of Health & Family Welfare, Government of India. Available from: https://www.mohfw.gov.in/pdf/. [Last updated on 2020 Mar 31].  Back to cited text no. 7


  [Figure 1]

  [Table 1]


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