Journal of the Scientific Society

EDITORIAL
Year
: 2020  |  Volume : 47  |  Issue : 2  |  Page : 59--62

Corona virus disease-2019 infection: Prevention and control


Gajanan S Gaude 
 Department of Respiratory Medicine, KAHER'S J. N. Medical College, Belgaum, Karnataka, India

Correspondence Address:
Dr. Gajanan S Gaude
Department of Respiratory Medicine, KAHER'S J. N. Medical College, Belgaum - 590 010, Karnataka
India




How to cite this article:
Gaude GS. Corona virus disease-2019 infection: Prevention and control.J Sci Soc 2020;47:59-62


How to cite this URL:
Gaude GS. Corona virus disease-2019 infection: Prevention and control. J Sci Soc [serial online] 2020 [cited 2020 Nov 28 ];47:59-62
Available from: https://www.jscisociety.com/text.asp?2020/47/2/59/294802


Full Text



Several cases of pneumonia of unknown origin were reported on December 8, 2019, from Wuhan, the capital of the Chinese province of Hubei. The initial cluster of cases was traced to the Huanan live animal and seafood market. The causative pathogen was then identified as an enveloped RNA beta coronavirus with genealogical similarity to the severe acute respiratory syndrome (SARS) coronavirus and named SARS-CoV-2. The disease that this virus causes has been termed coronavirus disease-2019 (COVID-19). SARS-CoV-2 is a new virus that has not been previously detected in humans. Of the two types of CoV (α and β), SARS-CoV-2 belongs to the category of β-coronaviruses.[1] The present SARSCoV-2 is the seventh coronavirus to infect humans. While SARSCoV-1, middle east respiratory syndrome-CoV and SARS-CoV-2 produce severe symptoms, the others produce relatively milder symptoms. Although coronavirus outbreaks have occurred many times in the past, none of them were of the magnitude as the present COVID-19 pandemic. In fact, this is the first pandemic to be spread by a coronavirus. Till June 3, 2020, COVID-19 has afflicted 6,272,098 patients worldwide and has caused 379,044 deaths. In India, till now, 207,615 cases have been confirmed to be suffering from COVID 19 and already 5815 deaths have occurred. The cases have been reported from all parts of the country, with the maximum number of cases being from Maharashtra, Gujarat, Delhi, and Tamil Nadu.

 WHO's Response to the Corona Virus Disease-2019 Pandemic



To tackle the COVID-19 pandemic, the WHO has launched the Strategic Preparedness and Response Plan (SPRP), which prioritizes public health measures in countries affected by the pandemic.[2] In February, the WHO requested the global community to donate for supporting its SPRP initiative. The SPRP is coordinating international efforts and providing operational support to strengthen the health systems of economically weaker countries so that they can tackle the COVID19 pandemic on a war footing. It is also expediting priority research and innovation for developing vaccines in a time-bound manner. The immediate objectives of the plan include: stopping human-to-human transmission of the virus; reducing transmission of the virus from animal reservoirs; identifying and isolating cases so that they can be treated as early as possible; communicating real-time information about the outbreak so that timely precautionary measures can be taken; and minimizing social and economic impact, especially for nations with weaker health systems.

 Mode of Transmission



Respiratory droplets production is the primary mode of COVID-19 transmission, which occurs when an infected person coughs, sneezes, or talks. Droplets that settle on the face or near the eyes, nose, or mouth of a person in close proximity leads to the transmission of infection. Transmission can also occur by touching the face with the contaminated hands of the individual. A distance of six feet away from an infected person may be considered as safe as the respiratory droplets do not remain suspended in the air for long.[3] Coronaviruses may contaminate metal, glass, or plastic surfaces that may remain infective for several days. Contact with such contaminated surfaces, which are called fomites and subsequent transfer to the face by touch, may also be an important mode of transmission. Airborne transmission, distinct from droplet infection, is characterized by viruses that drift through the air. It is unclear if airborne transmission occurs with COVID-19 infection. The possibility of airborne transmission requires the use of additional protective measures, including N95 masks.

R0, pronounced R-naught, is the basic reproduction number and indicates the transmissibility of a disease when special quarantining or isolation measures are not undertaken. In simple terms, R0 indicates the number of people to whom an afflicted person can transmit the infection. Preliminary analysis has reported R0 for COVID-19 infection to be between 2.2 and 3.6. The capability to transmit infection can be highly variable between individuals. There are some infected individuals who are capable of transmitting the disease to a much larger number of people than most others (high R0).[4] Such individuals with a high potential for transmission are called “super-spreaders.”

Principles of infection prevention and control

The strategies associated with health-care Infection Prevention and Control (IPC) strategies to prevent or limit the transmission of infection includes early recognition and source control, administrative controls, environmental and engineering controls, and personal protective equipment (PPE). Clinical triage, including early recognition and immediate placement of patients in separate areas (source control) is an important measure for rapid identification and appropriate isolation and care of patients with acute respiratory infection (ARI), including those with suspected COVID 19 infection. Critically ill patients may present to the emergency department from the community or by inter-hospital transfer to the intensive care unit. In such instances, a detailed inquiry should be carried out to ensure appropriate screening and infection control precautions should be followed.

Precautions also need to be taken to avoid the spread in high-dependency areas in the hospital, such as the emergency departments, intensive care unit, and dialysis units where COVID19 cases have shown to spread.[5] Hence, early isolation of these cases in negative suction rooms has to be done at the earliest, and thus mixing of these cases with other cases has to be avoided. Clinical and epidemiological aspects of the cases should be evaluated as soon as possible and should be complemented by laboratory evaluation to confirm the diagnosis. Once the diagnosis is confirmed, primary and secondary contact tracing has to be done as advised by ICMR.

Early diagnosis and isolation

early diagnosis of COVID 19 infection is important so that the persons and be isolated immediately and spread of the infection in the society can be prevented as early as possible. Developments of new technologies are urgently needed for the diagnosis of Covid-19. Most laboratory testing has been based on viral nucleic acid assay. Reverse transcription-polymerase chain reaction technique for the diagnosis of the infection has been utilized worldwide, and the results are available within 2 h. The rapid immunoglobin M assay kit for detecting SARS-CoV-2 with only a drop of blood (~10 μl) has also been developed, with the results being available within only 15 min and online analysis with the smartphone, but still requires to undergo further testing at community levels. Unfortunately, no targeted therapy exists for COVID 19. Supportive therapies (i.e., oxygen supplementation, antibiotics) have been implemented with modest outcomes. Although several antiviral medications (i.e., remdesivir, chloroquine, and loparinir/ritonavir) have been adopted for compassionate therapy without clear evidence of benefit. More than 300 clinical trials have been initiated worldwide with multiple drugs, including convalescent plasma and stem cell therapy.[6] Hence, all the confirmed cases of COVID 19 infection has to be isolated either at home or at the institution depending upon the severity of the illness and presence of the underlying co-morbid conditions. ICMR has given clear-cut guidelines regarding the isolation strategies.

Environmental and engineering controls

Although the predominant mode of transmission of COVID-19 disease appears to be through droplet and contact with respiratory secretions, the airborne transmission may occur, and appropriate precautions are recommended in high-risk situations, especially when treating patients who are critically ill. Isolation rooms with negative pressure and frequent air exchanges are advisable for suspected and confirmed cases of COVID19 cases.[7] If sufficient airborne isolation areas are unavailable, patients should be accommodated in single rooms behind closed doors. To reduce or eliminate the exposure of health care workers (HCWs) to the patients, the hospital rooms have to be designed to reduce the infection chances. Examples of engineering controls include physical barriers or partitions to guide patients through triage areas; curtains between patients in shared areas; and air-handling systems (with appropriate directionality, filtration, exchange rate, etc.,) that are properly installed and maintained. Anterooms to enable caregivers to put on (don) and remove (doff) PPE should also be available. The use of high-flow nasal oxygen, nebulizers, noninvasive ventilation (NIV), bag-mask ventilation, the performance of laryngoscopy and endotracheal intubation are likely to generate aerosols, which may predispose to the transmission of the virus. HCWs should be aware of this aerosol generation, and precautions should be taken appropriately or unnecessary procedures should be avoided.

Administrative controls

Administrative controls and policies that apply to COVID19 include the establishment of sustainable IPC infrastructures and activities; HCW training; patients' caregivers education; contact tracing of the positive cases, home or institutional quarantining of the cases; prompt laboratory testing of suspected cases; prevention of overcrowding especially in the Emergency Department; and appropriate placement of hospitalized patients promoting an adequate patient-to-staff ratio; provision and use of regular supplies; IPC policies and procedures for all facets of health-care provisions-with emphasis on surveillance of ARIs among HCWs and the importance of seeking medical care; and monitoring of HCW compliance.[8]

Personal protective equipment

HCWs who care for critically ill patients with suspected or confirmed COVID-19 disease must use PPE. Operating room scrubs or full coveralls should form the first layer of protection beneath PPE. The PPE must include fluid-resistant gowns and gloves, goggles with side protection, hair covers or hoods, and fit-tested N95 respirator masks. Caregivers should also wear disposable shoe covers or water-resistant shoes that can be decontaminated. Doffing of PPE should be carried out carefully, with diligent hand hygiene after removal, as many of the cases of infection transmission among HCWs took place because of incorrect technique.[9] A powered air-purifying respirator is often recommended and may offer greater protection compared to N95 masks. It consists of a respirator worn as a hood; it draws in and filters potentially contaminated ambient air, and delivers clean, decontaminated air to the user through the hood. When providing care in close contact with a patient with respiratory symptoms (e.g., coughing or sneezing), use eye protection (face-mask or goggles), because sprays of secretions may occur. Limit patient movement within the institution and ensure that patients wear medical masks when outside their rooms for source control and to diminish the potential for environmental decontamination.[10] Ensure that triage and waiting areas are adequately ventilated. If possible, use either disposable or dedicated equipment (e.g., stethoscopes, blood pressure cuffs, and thermometers). If equipment needs to be shared among patients, clean and disinfect it between each patient use. Ensure that HCWs refrain from touching their eyes, nose, or mouth with potentially contaminated gloved or ungloved hands. Avoid contaminating environmental surfaces that are not directly related to patient care (e.g., door handles, and light switches). Ensure adequate room ventilation. Avoid movement of patients or transport. Perform hand hygiene frequently.

High flow nasal oxygen, noninvasive ventilation, and nebulizer use

Droplet and aerosol spread may occur during therapeutic interventions among patients with COVID-19 disease. When administering oxygen through nasal prongs, the patient's face may be covered with a surgical mask to prevent droplet spread. The use of a high-flow nasal cannula may lead to aerosol generation; hence, it should be used only in locations that provide airborne isolation and in negative pressure rooms. Nebulized medications are best avoided due to the possibility of aerosol generation; metered-dose inhalers with spacers may be used as an alternative, especially in patients with asthma and COPD. Although a few patients in hypoxemic respiratory failure may be managed with NIV, extensive disease transmission may occur over a wide area, as noted during the SARS epidemic.[11] Besides, NIV use may delay intubation leading to patient deterioration and inadequate donning of PPE during emergent intubation. As a general rule, high-flow nasal cannulae and NIV should be used sparingly, and never outside a suitable location with droplet and airborne isolation.

Summary

Beginning late 2019, a novel coronavirus led to the global outbreak of an acute respiratory illness, currently designated as COVID-19 disease. The rapid spread has occurred across several geographical locations within the first few weeks. A large number of patients develop pneumonic infiltrates. The disease appears to mainly affect adults between the age of 30–79 years, with a male preponderance. The large majority of patients appear to develop the mild disease, and the overall mortality appears to be low (2%–3%). However, higher mortality has been observed among elderly people and those having underlying co-morbid conditions. HCWs are at high risk of acquiring the infection, and hence, appropriate infection control measures are crucial in reducing disease transmission. Screening, triage, and isolation of patients are important among those with confirmed disease and at high risk of infection.

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