|Year : 2020 | Volume
| Issue : 1 | Page : 7-16
COVID 19: Understanding the Disease to Implement Containment Strategies
Kirti Singh1, Jatinder Bali2, Arshi Singh3, Nandini Sharma4
1 Department of Ophthalmology, Maulana Azad Medical College, New Delhi, India
2 Narela Polyclinic, New Delhi, India
3 Department of Ophthalmology, Baba Saheb Ambedkar Hospital, New Delhi, India
4 Department of Community Medicine, Maulana Azad Medical College, New Delhi, India
|Date of Submission||05-Apr-2010|
|Date of Acceptance||05-Apr-2020|
|Date of Web Publication||30-Apr-2020|
MD, DNB, FRCS, FAIMER Kirti Singh
Department of Ophthalmology, Maulana Azad Medical College, New Delhi
Source of Support: None, Conflict of Interest: None
COVID-19, the novel coronavirus is a global threat which has hit all with the force of a hurricane. The vast biological and economic impact of this virus threatens to crumble our health resources, if not handled with caution. In order to battle this pandemic on all fronts, awareness of nature of virus, its transmission, virulence clinical features, complications and management options is essential. We as comprehensive ophthalmologists and more importantly as responsible clinicians, need to update ourselves with knowledge pertaining to this novel virus to safeguard our human resources including ourselves against this powerful enemy. The article reviews basic information about etiology, transmission patterns, clinical picture, diagnostics, treatment and preventive measures of this infection. This is in concordance with the maxim “Know thy enemy”. It also stresses on the precautions to be observed by all healthcare personnel to ensure safety and contain spread. We bear onus of becoming aware of spreading this awareness to break the chain of contagion.
Keywords: Containment strategies, COVID 19, morbidity, ophthalmologist, personal protection, treatment options
|How to cite this article:|
Singh K, Bali J, Singh A, Sharma N. COVID 19: Understanding the Disease to Implement Containment Strategies. MAMC J Med Sci 2020;6:7-16
|How to cite this URL:|
Singh K, Bali J, Singh A, Sharma N. COVID 19: Understanding the Disease to Implement Containment Strategies. MAMC J Med Sci [serial online] 2020 [cited 2020 May 28];6:7-16. Available from: http://www.mamcjms.in/text.asp?2020/6/1/7/283504
| Introduction|| |
Since times immemorial human pandemics have been caused by zoonotic diseases like plague and anthrax, with devastating outcomes. The pattern of zoonotic infections has expanded with new diseases like Ebola, human immunodeficiency virus (HIV), severe acute respiratory syndrome-Corona virus 1 (SARS-CoV), middle East respiratory syndrome (MERS), avian influenza, swine influenza and Zika virus emerging over last few decades. Most of these diseases have been linked to infringement into animal habitat by close contact, trade or consumption of live animal food. The 2020 pandemic of Coronavirus COVID 19 linked to a seafood “wet market” in Wuhan, China is the latest zoonosis to devastate the world. This is the third serious Coronavirus outbreak in less than 20 years, following Severe acute respiratory syndrome outbreak (SARS) in 2002–2003 and Middle East respiratory syndrome outbreak (MERS) in 2012. [Table 1] Genomic sequencing has identified the COVID 19 to be a novel coronavirus with an 85% homology to SARS-CoV 1. Bats have been implicated as primary hosts and pangolins or snakes as intermediate hosts., Chronic exposure to the intermediate hosts at the Huanan live sea food market in Wuhan, was responsible for the first animal to human transmission.
| Understanding the Disease Profile and Presentations|| |
Coronavirus (CoV) morphology
Coronaviruses are round to oval, non-segmented, positive-sense, RNA viruses. These enveloped virus have a diameter ranging from 60 to 140 μ. The name Corona is derived from presence of club shaped glycoprotein spikes on the envelope of the virus, giving it a crown-like appearance. These spiked proteins facilitate virus entry into cells and contribute to its pathogenicity [Figure 1]. These virus have the largest genomes for RNA virus and are prone to develop mutations. Their natural habitat is bats with camels, civets and pangolins being the intermediate hosts from which source human transmission occurred in the last three pandemics.
The Coronaviridae family is of order Nidovirales and has subfamily Orthocoronavirinae with four genera of CoVs. These are: Alphacoronavirus (alphaCoV), Betacoronavirus (betaCoV), Deltacoronavirus (deltaCoV), and Gammacoronavirus (gammaCoV). The virus has four main structural proteins namely spike, membrane, envelope and nucleocapsid proteins., The spiked protein is being subjected to research in an endeavor to develop a vaccine.
The incubation ranges from 2 to 14 days post- exposure, with a median time of 5–7 days. Isolated reports of current pandemic suggest that 97% of symptomatic cases resolve within 11.5 days of exposure., Thus a 14-day quarantine recommendation suffices for containment.
Initial zoonotic transmission was from a sea food market. In the 41 hospitalized index cases of Wuhan, live seafood exposure was identified in 66%. Human to human transmission occurs by droplets/aerosolized particles and fomites. The virus remains stable for hours to few days in both aerosols and surfaces. In vitro studies have demonstrated the virus retaining viability in aerosols for 3 hours, on cardboard for 1day and on plastic and stainless steel from 1–3 days.
Fecal transmission has not been ruled out as presence of virus has been demonstrated in 50% of a cohort of patients admitted in Singapore.
Transmission by tears and contact with conjunctival mucosa is possible. The virus has been demonstrated in one patient in a series of 30 sputum positive patients. As this patient had conjunctivitis, the authors opine conjunctival secretions to become infected only in presence of conjunctivitis. Case reports document infection of ophthalmologists during routine examination of patients.,, The tragic demise of Li Wenliang, an ophthalmologist who contracted the disease while examining a patient with glaucoma during the asymptomatic phase of the latter.
Vertical transmission from mother-to-child has so far not been documented. A study on 9 pregnant women who developed COVID-19 pneumonia in late pregnancy documented no evident abnormalities in children born to them.
Coronavirus causes respiratory, enteric, hepatic, and neurological diseases in many animal species, including camels, cattle, cats, and bats. Prior to current pandemic, 6 corona virus’ resulting in zoonotic disease have been identified, namely: CoV-229E, HCoV-HKU1, HCoV-OC43, HCoV-NL63, SARS-CoV and MERS-CoV. Coronavirus in human to human transmission has been implicated in 5%-10% of acute respiratory infections. In immunocompetent individuals it causes common cold and upper respiratory infections, involvement of lower respiratory tract is seen in the immunocompromised and elderly. Cross species jumps have resulted in 2 outbreaks of SARS-CoV in 2002, and MERS-CoV in 2012, the latter is still producing fresh cases. These two strains were highly virulent and caused infection of both respiratory and gastrointestinal systems, with case fatality rate (CFR) rates of 10 and 35% respectively., The current pandemic with SARS − CoV 2 has so far been responsible for less mortality compared to SARS & MERS, with most infections being mild and self- limiting in 80% patients, with critical disease in only 5% cases. The virus however has demonstrated very high transmissibility (high reproductive number Ro), which has resulted in unprecedented spread across countries and therefore far actual deaths.
Clinical presentation in current pandemic
The current strain CoV-2 (COVID-19) predominately attacks lower respiratory tract and has a propensity to spread rapidly. This is evident from statistics of spread from a single city Wuhan, to engulf entire China within 30 days and then cross geopolitical borders to incapacitate almost 200 countries over a short period of 3 months.
Study of hospitalized patients have identified fever as the predominant symptom in 83%–99%, fatigue in 70%, dry cough in 59%–82%, myalgia in 11%–35% and dyspnoea in 22%–31% cases.,,, Headache, sore throat, rhinorrhea, confusion, chest pain and diarrhea have been less commonly noted.
Critical illness requiring ICU facilities has been documented in 26%–32% of hospitalized cases during the Wuhan epidemic phase., Pneumonia, acute respiratory distress syndrome, dysarrhythmia, multi-organ failure and anemia are the common indications for ICU admission. Time within which patients can require ICU facilities is short, usually within 5-8 days of admission.,
The (CFR) ranging from 2.3% to 7% appears to be lower than observed with SARS or MERS, till date., The mortality rates in those with critical illness requiring ICU care is much higher at 17%–62%.,, The cause of death is by multi-organ damage primarily, acute respiratory distress syndrome, renal failure, liver failure or cardiac damage. At the time of writing, COVID 19 has accounted for more deaths than either of the previous outbreaks at 27,441 as the sheer number of cases involved have been more.
Patterns of vulnerability
The disease affects people differently. Older age and patients with systemic comorbidities are more afflicted.,, The largest report of 72,314 cases by Chinese Center for Disease Control and Prevention documents a case fatality rate of 8% in older patients aged 70-79 years and almost 15% in those above 80 years, with no deaths reported in children. 20 This discrepancy in CFR amongst ages is being touted as one reason for higher CFR in Italy, which houses an older population. The disease also progresses more rapidly in older people and is milder in children. One explanation for this resilience in children is the immaturity of ACE 2 receptors required for viral entry in children, and this aspect needs further research in the quest for a treatment.
Patients with comorbidities of cardiovascular disease, diabetes, hypertension, malignancy are more likely to have more severe disease and require critical care.,, Data from hospitalized patients reports comorbidities in 24%–51%. The patients in ICU from the disease are two times more likely to have such comorbidities. Smoking has been implicated to increase the risk of patients having severe disease by 1.4 times and risk of ICU admission by 2.4 times.
Geographic patterns are emerging, with Singapore reporting less severe cases with lower requirement of ICU facilities of 11%–15%., The belts with malaria endemicity are being touted as having relative immunity to this virus, but at this stage of the pandemic, this still remains a conjecture. Psychoneuroimmunology aspects may hold the key to understand these vulnerability patterns.
The COVID-19 virus initiates an inflammatory cytokine storm and disrupts immune and coagulation functions. Lymphocytes are targeted and lymphocytopenia is a common occurrence at 64%–80% cases.,, Few authors have however described lymphocytosis and leucocytosis to be the prominent finding Leukopenia, lymphocytosists, anemia, mild thrombocytopenia have also been reported. Coagulation profile, liver and kidney function tests are deranged with elevated liver transaminases and elevated LDH.
Early surrogate evidence of disease severity has been studied in detail. Biochemical markers which could be studied are: lymphocytopenia, elevated C − reactive protein (CRP), D-Dimer with longer prothrombin time, activated partial thromboplastin time, elevated procalcitonin, severe thrombocytopenia.,,,
Qualitative immune-chromatography (COVID-19 Rapid Test) detects Immunoglobulin (Ig) G and IgM antibodies to SARS-CoV-2 in human whole blood or plasma. This IgM-IgG combined assay has better utility and sensitivity compared to single IgM or IgG test.
Nasopharyngeal and oropharyngeal swab sample need to be taken for diagnosis. Collection is done under strict airborne infection control precautions, preferably in negative pressure rooms (40mm of Hg). The health care worker taking the samples is to do so under full personal protective gear. For best isolation samples are taken at symptom onset till fifth day. Bronchoscopy for sampling purposes is to be avoided due to risk of aerosol generation and further transmission.
Molecular tests are performed to differentiate from influenza A and B. In situation of negative test in presence of strong clinical suspicion, samples from multiple sites like nose, sputum and endotracheal aspirate are taken and re-tested. Reverse transcriptase polymerase chain reaction (RT-PCR) for SARS-CoV-2 RNA test provides report within hours. For safety reasons, COVID-19 should not be submitted for viral culture.
- Chest Radiography findings are non-specific with findings of bilateral pneumonia in 75%–100% of hospitalized cases.,, Ground glass opacities, multiple mottling are common patterns reported in 56% cases. Normal chest imaging does not rule out development of severe illness and has been reported to occur in 17% of non-severe and 3% critical cases respectively.,
- Computed Tomography Chest. Four stages of the disease manifestations have been described depending on time the line after symptoms., Early stage (0–4 days): ground glass opacities with sub-pleural distribution in lower lobes on X ray Progressive stage (5–8 days): involvement of both lungs and multi-lobe distribution with ground glass opacities, crazy-paving and consolidation of airspaces. Peak stage (9–13 days): Denser consolidation and residual parenchymal bands. Absorption stage (>14 days): Persistent ground glass opacities Interlobular septal thickening (smooth and irregular), air bronchogram and irregular pleural thickening of subpleural regions and lower lobes, have also been reported.
- Lung Ultrasound is non- specific and depicts irregular pleural lines, sub-pleural areas of consolidation, areas of white lung and thick B lines.
- Pulmonary function tests (PFT): due to high risk of cross infection in pulmonary function lab arising from direct and aerosolized particle contact, these are to be avoided.
| Discharge of Infected Cases|| |
The patients are discharged on resolution of symptoms, radiological improvement and documented virological clearance in 2 samples at least 24 hours apart. Samples should be disposed, after donning personal protective gear, in the yellow bin as per biomedical waste guidelines.
The disease causes morbidity by two phases, the virus mediated followed by exaggerated immune response. Treatment protocols differ for the two with antiviral therapy required for the first phase and immune dampening for the latter. Definitive therapy currently is based on anecdotal evidence extrapolated from previous outbreaks of SARS-CoV1. Supportive therapeutic regimens are more relevant as of now.
Anecdotal evidence suggests “off label use” of certain drugs. Many drugs were tried for SARS CoV1, their use is being extrapolated to COVID 19.,, A brief outline of them is given below.
Oseltamivir a neuraminidase enzyme inhibitor has been used in influenza in dose of 75 mg BID for 5 days.
Remdesivir, an investigational RNA dependent RNA polymerase inhibitor drug, needs to be given by IV route, as 200 mg loading dose followed by 100 mg daily for 9 days. Hepatotoxicity has been reported with its use.
Lopinavir/ Ritonavir −viral protease inhibitor, has been found to reduce MERS viral replication in vitro by 50%. It is given orally 400/100 mg 5ml suspension BD or 400/ 100 mg BD for 14 days. The drug has been associated with QT prolongation and hepatotoxicity.
Ribavirin- a nucleotide analog, it prevents viral replication by inhibiting RNA dependent RNA polymerization. The drug is given as a loading dose of 2.4 gms followed by 1.2 gm BD for 10 days. It carries a high risk of causing haemolytic anaemia.
Camostat and Nafamostat −are serine protease inhibitors which prevent fusion process thereby prevent virus from entering cell. Side effects being pancreatitis and coagulation defects
Azithromycin − is used to prevent secondary infection. Dose is 500 mg loading dose, followed by 250 OD for 4 days.
Chloroquine- an immunomodulator, the drug has been proven to be highly effective to reduce viral replication. It acts by increasing endosomal pH and interfering with glycosylation of cellular receptors of SARS-CoV-2 virus. The dose regimen is variable. Expert consensus on chloroquine phosphate states use of 500 mg BD for 10 days, in patients without contraindication. The drug can cause blood dyscrasia, prolonged QT interval and bradycardia.
ACE inhibitors − prevent binding of viral S protein with ACE receptors of host cell, thereby preventing cell entry, an example being Emodin.
Tocilizumab, a monoclonal antibody to IL6 receptor. It reduces cytokine storm. The dose recommended is IV 4–8 mg/kg, over one hour
Interferon alpha & Beta and immunoglobulin, could inhibit production of pro-inflammatory cytokines. Their use could be considered in patient with lympho/leukocytopenia.
Convalescent serum therapy is an option to reduce mortality., The plasma is obtained from a donor who has recovered from the illness by developing humoral immunity against the virus. It is useful when given early on in the disease.
As per current Government of India, Ministry of Health & family welfare (MOHFW) recommendation Lopinavir/ Ritonavir, may be used only with proper informed expressed consent for severe cases with hypoxia or hypotension or new onset organ dysfunction or increase in creatinine by 50% from baseline, glomerular filtration rate (GFR) reduction by >25% from baseline or urine output of <0.5 ml/kg for 6 hours or Reduction of GCS by 2 or more or any other organ dysfunction.
They may also be used in high risk groups. High risk groups are defines as −age> 60 yrs, presence of diabetes mellitus, renal failure, chronic lung disease, immuno − compromised persons. Dosage: Lopinavir/ Ritonavir (200 mg/ 50 mg), 2 tablets BID. For patients’ unable swallow tablets 5 ml suspension of Lopinavir 400mg/ Ritonavir 100 mg is given BID. The drug is continued for 14 days or 7 days after becoming asymptomatic.
Chemo-prophylaxis: This is suggested for high risk population and Indian Council of Medical Research (ICMR) national task force of COVID 19 has recommended Hydroxychloroquine in a loading dose of 400 mg followed by 400mg twenty four hours later and thereafter 400mg once a week for 6-7 weeks for chemo-prophylaxis.,, The drug hampers low pH dependent steps of viral replication and is recommended for asymptomatic health care workers involved in care of suspected or confirmed cases of COVID 19 or for asymptomatic contacts of laboratory confirmed case. The detailed results from randomized clinical trials are awaited at this current moment for hydroxychloroquine and chloroquine.
- Oxygen support to maintain oxygen saturation above 90% is given.
- Fluid management
- Ventilation support (ARDS NET protocol) − “lung protective ventilation” at low tidal volume, low pressure ventilation. Extra corporeal membrane oxygenation can be an option for refractory hypoxemia.
- Broad spectrum antibiotics as per hospital protocol for secondary bacterial infection
- Corticosteroids prolong viral shedding and are used to dampen the exaggerated immune response and reduce cytokine induced injury.
Vaccine trials are underway. A NIH clinical trial of investigational vaccine at Kaiser Permanente Washington Health Research Institute (KPWHRI), Seattle, USA has been initiated. The lipid nanoparticle encapsulated mRNA “mRNA-1273” vaccine developed jointly by National Institute of Allergy and Infectious Diseases (NIAID) and Moderna, Inc Cambridge, Massachusetts is being tested on 45 healthy adult volunteers, over a 6 week period. The trial has been expedited to Phase 1. 28
| Disease Spread Dynamics, Surveillance and Public Health Strategies|| |
Case definitions (as per WHO-China joint commission report)
Suspected case is a patient with sudden acute respiratory tract infection (SARI) with at least one of the following: cough, fever, shortness of breath AND with no other etiology that fully explains the clinical presentation AND with a history of travel or residence in a country/area reporting local or community transmission during the 14 days prior to symptom onset.
OR A patient with any acute respiratory illness AND having been in close contact with a confirmed or probable COVID-19 case in the last 14 days prior to onset of symptoms.
OR A patient with severe acute respiratory infection (fever and at least one sign/symptom of respiratory disease (e.g., cough, fever, shortness breath) AND requiring hospitalization (SARI) AND with no other etiology that fully explains the clinical presentation.
Probable Case is a suspected case for whom laboratory testing for virus causing COVID-19 is inconclusive or for whom testing was positive on a pan-coronavirus assay.
Confirmed Case is a person with laboratory confirmation of virus causing COVID-19 infection, irrespective of clinical signs and symptoms.
Close Contact of a probable or confirmed case is defined as
a person living in the same household as a COVID-19 case
A person having had direct physical contact with a COVID-19 case (e.g. shaking hands)
A person having unprotected direct contact with infectious secretions of a COVID-19 case (e.g. being coughed on, touching used tissues with bare hands)
A person having had face-to-face contact with COVID-19 case within 2 meters and > 15 minutes
A person who was in a closed environment (e.g. classroom, meeting room, hospital waiting room, etc.) with a COVID-19 case for 15 minutes or more and at a distance of less than 2 meters
A healthcare worker (HCW) or other person providing direct care for a COVID-19 case, or laboratory workers handling specimens from a COVID-19 case without recommended personal protective equipment (PPE) or with a possible breach of PPE
A contact in an aircraft sitting within two seats (in any direction) of the COVID-19 case, travel companions or persons providing care, and crew members serving in the section of the aircraft where the index case was seated (if severity of symptoms or movement of the case indicate more extensive exposure, passengers seated in the entire section or all passengers on the aircraft may be considered close contacts)
Super spreaders are hosts who spread the infection to too many susceptible hosts. Various factors contributing being physiological, behavioural, immunological nature of hosts and virulence of pathogen
The disease evolves over 6 phases as per WHO guidelines.
- Phases 1 − is restricted to animal (wild /domesticated), with no animal-human transmission
- Phase 2 − the zoonotic virus crosses over to infect humans
- Phase Three − sporadic/ small clusters of disease occurs in humans without any human to human transmission
- Phase Four- human to human transmission occurs causing community outbreaks
- Phase Five − community-level outbreaks occur in > 2 countries in a single region
- Phase Six − community-level outbreaks transcend regional boundaries. This stage is “a pandemic”.COVID-19 outbreak was declared as a pandemic by WHO on March 11, 2020. Post Peak − numbers of infected humans decline below peak level cases in the country.
Post Pandemic: cases decline further to level of number of seasonal flu cases across countries with active surveillance.
ICMR guidelines are restricted to four phases
- Imported cases: Reported cases have travelled from infected countries
- Local Transmission: Person comes in close contact with a positive case. Contact is further defined as:
- A person providing direct care without proper personal protective equipment (PPE) for COVID 19 patient
- Staying in same close environment as COVID 19 patient (workplace, classroom, household gathering)
- Travelling together in close proximity (1 m) with a COVID 19 patient in any kind of conveyance within a 14 day period after the onset of symptoms in the case under consideration
- Community Transmission: When people without any travel history or close proximity to a positive person, develops the disease
- Epidemic: The disease spread is exponential
| Explanation for Enhanced Spread of Sars- Covid 19?|| |
An unanswered question is the unprecedented spread of this virus, which is otherwise so similar in characteristics to SARS −COV. The probable explanation for this is the following
- Pathogenicity of the virus: This is denoted by Basic reproductive number (R0) which reflects average number of secondary infections that a patient may produce in completely susceptible population without intervention. For COVID 19, R0 values range from 2-6.6, which means a single case can infect 2-6 cases, thereby enhancing local transmission.,, The high transmissibility of SARS-CoV-2 is more than SARS or MERS, which have R0 values of 2-4 and 1 respectively.
- SARS-CoVe −2 is a RNA virus which has higher mutation rates thereby giving it adaptive survival for eye.
- The spread coincided with Chinese Lunar New year, involving largest human migration in the world with over a 3 billion journeys.,
- Some COVID-19 positive patients also become super spreaders, thereby increasing local transmission. Factors for super spreading events are categorized into pathogen related, host related and environmental related The latter include crowding, social gathering, inter-hospital transfers and airflow dynamics in workplace /home
- Live virus can be recovered from asymptomatic or mildly symptomatic people, making the disease contagious even in the latency period.,
| Containment Strategies|| |
As already established, lack of treatment makes it imperative to swing in measures to control this highly infectious disease. These strategies are: screening at entry ports followed by isolation/ quarantine of suspected cases and placement of “cordon sanitaire” (sealing of boundaries of cities / countries) to prevent human movement and thereby confine disease. India has adopted all and the latter from 23rd March 2020.
Who are to be isolated?
- Cases tested laboratory positive for SARS CoV 2
- Cases with fever and SARI, with history of close contact with person diagnosed as COVID-19, or history of travel to a COVID affected region within last 14 days
- Health care workers with fever and respiratory illness who has been involved in treating COVID- 19 patients, or has close contact with persons involved in treating COVID- 19 patients during last 14 days.
Where and How to be isolated ?
- Designated hospital wards / floors in well ventilated, preferably separate rooms with toilets.
- Patient should wear face mask as long as tolerated
- Unnecessary investigations requiring shifting of patient to be avoided
- Monitoring is done by dedicated medical team.
- Isolation is continued till 2 consecutive respiratory samples taken 24 hours apart, test negative.
This is for asymptomatic cases with exposure to Covid-19 positive patients. Quarantine can be done at their residences under strict surveillance to prevent breaking the cordon.
These are being widely practiced and involve Social distancing to break the chain of transmission. These are currently being practiced in countries with lockdown such as India. A few of them are described below:
- Non-essential services to be curtailed. Employees asked to work from home wherever feasible. Public gatherings for festivals, entertainment or religious purposes banned
- All face to face meetings, exams, events cancelled. Focus on digital meetings
- Hand hygiene- Water or 60% alcohol content sanitizers to be used for hand hygiene. Greetings involving hand or physical touch need to be strictly avoided
- Disinfection/decontamination: Surface cleansing disinfection to kill the virus, which can survive on surfaces for several days. Potentially contaminated areas to be cleaned with sodium hypochlorite 1% solution. Floors need to be cleaned with wet mopping using detergent/ hot water / 1% sodium hypochlorite at least 2 times a day.
- In hospital or quarantine settings “spill care” is done with absorbent paper followed by 1% sodium hypochlorite for 20–30 minutes contact time. Waste is disposed in yellow coloured infectious bin, and area mopped with soap and hot water.
Risk and recommendations for health personnel including ophthalmologists
Health workers are at the forefront of this pandemic. Chinese disease control and prevention centre in its report of 72314 cases, documents 3019 suspect infections in health workers, of which 1716 were confirmed, translating into incidence of 3.8%. Critical disease occurred in 15% of infected health workers, which resulted in five deaths. High risk exposure occurs in departments with interventional medical or surgical procedures generating aerosols like respiratory medicine, infectious disease, anaesthesiology, all surgical departments and ICU. A retrospective cohort study has identified a 2.1 times higher risk in of developing the disease for workers in there departments. The same study identified longer duty hours and suboptimal hand hygiene to be the major determinants of disease acquisition. Suboptimal hand hygiene had a 2.4-3.0 relative risk of disease development.
Of all specialties ophthalmologists, otorhinolaryngologists and dentists are at maximal risk of secondary infection by aerosol or droplet transmission. The reasons for these are the following:
- The reliance of physical examination and proximity of doctor with patient during slit lamp use, makes the ophthalmologist vulnerable to both droplet and aerosol transmission. Since droplets can be transmitted to a 6 m distance during cough/ sneeze, the eye physician by nature of his proximity to patient’s mouth and nose is very vulnerable.
- Conjunctival secretions or tears as infective medium- Tears and conjunctival mucous membrane can transmit the virus. Many reports have surfaced with ophthalmologists infected during examination of patients.,, The first doctor fatality of ophthalmologist, Dr Li Wenliang is proof of the same. The tragic case highlights the need for great precaution during examination, as the patient examined by Dr Li presented with acute angle closure glaucoma during the asymptomatic period of his COVID 19 illness. Patients may present with conjunctivitis as an initial presentation, however, this is rare and was seen in only 0.8% cases during Wuhan epidemic. A study by Xia J et al has put forward the theory that conjunctival secretions are infective only if the patient with COVID present with conjunctivitis. This was borne out by their positive samples for virus in only 1 case of 30 sputum positive COVID −19 patients, the one positive case presenting with additional conjunctivitis.
Disease containment in hospital settings
Disease containment measures in hospitals/clinics require a 3 pronged approach. Administrative control, environmental control and use of PPE.
- Administrative control: Patient load reduction by generating patient awareness to self-medicate for trivial illness, triaging, suspending elective procedures. Fever screening at entry, staff training for hand hygiene, donning and doffing of PPE. Implementing disaster management by creating multi-specialty teams, reserve teams, travel restrictions and stocking of essential items including protective gear. Staff preparedness by self-monitoring for suspicious symptoms (fever, myalgia, sore throat, cough, vomiting, diarrhoea or pneumonia). Travel histories to be collected for all staff and patients. Cluster analysis and isolation to be performed in suspect cases. Staff roster should ensure restricted duty shifts to be less than 6–8 hours.
- Environmental control: Social distancing aspects to be worked out, 1–2m distance maintained. Reduce droplet spread by reducing aerosol generating procedures to bare minimum, ensuring ventilation/air change by high efficiency particulate air (HEPA) filters, minimize talking with patients. Floor and instrument moping with 0.5%–1% sodium hypochlorite twice a day. Provision of disposable or cleanable shields for slit lamps. Universal precautions to be practiced for front line workers. Sanitizing cell phones, medical equipment frequently in between patients.
- Personal Protective Equipment (PPE): Protective gear use (3 ply mask, goggles, non −sterile gloves, shoe covers) to be made mandatory for regular patient interaction. For higher risk patients at designated areas full personal protective equipment including isolation gown, gloves, cap, eye protection, surgical mask (or N95 respirator when necessary) to be used. Hand hygiene and hand held instrument sanitization after each patient. Details of protection levels are given in [Table 2].
|Table 2 Courtesy: Hospital Infection Control Division, Prevention and control of SARC-CoV-2 infection in hospital. Maulana Azad Medical College, New Delhi|
Click here to view
[TAG:2]Covid-19-related Personal Protection Management [/TAG:2]
Additional measures to be adopted by ophthalmologist for treating patient:
- Screening of patients at entry: Thermal screening and targeted questions as to contact with COVID case, travel to another country / state, acute respiratory illness symptoms like cough or dyspnea. If positive, escort patient to designated flu centre.
- The designated worker is given Level 2 protection with N 95 mask and non-sterile water-resistant gown and gloves
- Triage patients at entry. Elective investigations like refraction and elective surgeries to be deferred till situation is controlled
- The designated worker is given Level 2 protection with N 95 mask and non-sterile water-resistant gown and gloves
- Avoid aerosol generating procedures like Non-contact tonometry
- Direct ophthalmoscopy to be discontinued
- For essential contact procedures like tonometry, I and D, the doctor must wear full personal protective equipment which includes cap, N 95 mask, gown, double gloves and face shield
- Slit lamps can have protective shield installed, can be fabricated by stiff plastic or utilized X ray film
- Surgical emergency cases to be performed with surgeon and assistant donning full PPE
Way forward for India
- Capacity building by increasing number of laboratory tests to detect asymptomatic cases
- Protection of health care workers and first responders (sub centres to super-specialty hospitals) at the front line of this pandemic. This includes steady supply chain of medical resources (masks, gloves, gowns, ventilators), and protection of healthcare workers (physical and psychological). Retired work force to be reinstated to combat the sudden shortage.
- Reserve tertiary care centres for the onslaught of cases by directing common ailments patients to primary health care set ups
- High burden of co-morbid conditions like TB, HIV/AIDS, and Diabetes would magnify the disease spread. Capacity building of existing facilities of Revised national Tuberculosis Control Program and National Aids Control Program would target these at risk population.
- Inequitable distribution of health-care facilities, needs to be overcome by strengthening public private enterprise.
- Using projection/forecasting by mathematical models specific for Indian scenario and accordingly allocate resources including manpower.
- Sanction fund and promote research on genome sequencing and vaccine development.
- For daily wagers, universal basic income to be assured to ensure social distancing and quarantine is maintained.
| Conclusion|| |
In there trying times health care system is facing an unprecedented crisis and needs to gird up to the challenges. A re-look into patient examination strategies, proviso for Telemedicine, and analytic approach for rational therapy is needed by the health care professionals. For this, awareness of virus behavior, it’s vulnerabilities is required to plan strategies for containment of disease.
This pandemic presages an introspection on human behaviour pertaining to aggressive infringement into animal habitat. A miniscule, invisible predator ignoring the geopolitical borders has shredded the ‘world wide web of life” within few weeks, thereby reiterating the lesson of international connectivity and collective responsibility. It is ironic that the start of 2020, has imparted this stupendous lesson of global vision to all.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]