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COVID 19_Vignesh.pptx

  1. 1/34 COVID-19 Dr D Vignesh (MD-AIIMS New Delhi) Asst. Professor ESIC Medical College & Hospital KK Nagar, Chennai
  2. 2/34 Pre-test •
  3. 3/34 Learning objectives Outline • Epidemiology of COVID-19 • Agent  Host  Environment • Burden and Risk factors • Diagnosis and Management • Control Measures
  4. 4/34 Background and Current burden • •
  5. 5/34 Epidemiology of COVID-19
  6. 6/34 AGENT • 7 human CoVs (HCoVs) Gene sources:- • AlphaCoVs and BetaCoVs:-Probably bats and rodents • DeltaCoVs and GammaCoVs:-Avian species • For reasons yet to be explained, these viruses can cross species barriers and cause illness ranging from minor URI to Severe Diseases like MERS and SARS • 2% of the population are healthy carriers of a CoV • These viruses are responsible for about 5% to 10% of acute respiratory infections. Coronaviridae family (Order Nidovirales) Alphacoronavirus 229E NL63 Betacoronavirus OC43 HKU1 MERS-CoV SARS-CoV SARS-CoV2 Deltacoronavirus Gammacoronavirus
  7. 7/34 ▪ Coronaviruses:- ▪ Single-stranded RNA viruses (+ssRNA) that can be isolated in different animal species. ▪ Crown-like appearance (coronam is the Latin term for crown) due to the presence of spike glycoproteins on the envelope ▪ SARS-CoV-2:- ▪ It has round or elliptic and often pleomorphic form ▪ Diameter is approximately 60–140 nm, +ss RNA is 30 kb in lenght (One of the largest known RNA viruses) ▪ Spike Glycoprotein- S1, S2 Subunits (S2- fusion peptide) STRUCTURE -INTERNATIONAL PULMONOLOGIST’S CONSENSUS ON COVID-19, 2nd Edition (
  8. 8/34 STRUCTURE
  9. 9/34 Host factors Original illustration by Dr. William Werbel, Infectious Diseases Society of America
  10. 10/34 ENVIRONMENTAL FACTORS • Temperature: • A lower environmental temperature favours persistence of virus on surfaces. • Overcrowding: • Enhances attack rate. Attack rates are high in close population groups eg. Ships, institutions. • pH: • Both high and low pH facilitates Virus reduction • It is sensitive to ultraviolet rays, and is effectively inactivated by lipid solvents including ether (75 per cent), ethnol, chlorine-containing disinfectants, peroxyacetic acid and chloroform except for chlorhexidine. • -INTERNATIONAL PULMONOLOGIST’S CONSENSUS ON COVID-19, 2nd Edition (
  11. 11/34 SOURCE/RESERVOIR • The persons infected by the novel coronavirus are the main source of infection. • Suspect, probable or confirmed. • Mild, moderate or severe
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  14. 14/34 DEFINITION OF CONTACT • Providing direct care without proper personal protective equipment (PPE) for COVID-19 patients • Staying in the same close environment of a COVID-19 patient (including workplace, classroom, household, gatherings). • Travelling together in close proximity (1 m) with a symptomatic person who later tested positive.
  15. 15/34 HIGH RISK CONTACT ▪ Touched body fluids of the patient (Respiratory tract secretions, blood, vomit, saliva, urine, faeces) ▪ Had direct physical contact with the body of the patient including physical examination without PPE. ▪ Touched or cleaned the linens, clothes, or dishes of the patient. ▪ Lives in the same household as the patient. ▪ Anyone in close proximity (within 3 ft) of the confirmed case without precautions. ▪ Passenger sitting in close proximity (within 3 ft) with a symptomatic person who later tested positive for COVID-19 for more than 6 hours.
  16. 16/34 LOW RISK CONTACT ▪ Shared the same space (Same class for school/worked in same room/similar and not having a high risk exposure to confirmed or suspect case of COVID-19). ▪ Travelled in same environment (bus/train/flight/any modeof transit) but not having a high-risk exposure.
  17. 17/34 Modes of transmission • Droplet • Droplet Nuclei • Fomite
  18. 18/34 FAECO-ORAL ROUTE ▪ SARS CoV 2 virus is enveloped ; unlike other enteric viruses like adenovirus, novovirus, rotavirus and hepatitis A. ▪ Presence of envelope makes it unstable in the environment compared to non-enveloped human enteric viruses with known waterborne transmission.
  19. 19/34 PETS: ▪ Several dogs and cats (domestic cats and a tiger) in contact with infected humans have tested positive for COVID-19. ▪ In experimental conditions, both cats and ferrets were able to transmit infection to other animals of the same species, but there is no evidence that these animals can transmit the disease to human and play a role in spreading COVID-19.
  20. 20/34 #breakthechain
  21. 21/34 INCUBATION PERIOD • The median incubation period is 5.1 days (range 1–14 days). • The precise interval during which an individual with COVID-19 is infectious is uncertain. • As per the current evidence, the period of infectivity starts 2 days prior to onset of symptoms and declines rapidly within the first week of symptom onset. • The duration of RT-PCR positivity generally appears to be 1-2 weeks for asymptomatic persons, and up to 3 weeks or more for patients with mild to moderate disease. • In patients with severe COVID-19 disease, it can be longer.
  22. 22/34 PATHO-PHYSIOLOGY • Predominantly have a respiratory tract infection • a small proportion can progress to a more severe stage : dysregulated immune response with hyper-inflammation with subsequent development of ARDS. • Hypoxemia, secondary to ARDS may also activate the coagulation cascade thereby creating a vicious circle. • Autopsy findings: • endothelial damage of pulmonary vasculature (Endothelialitis) • microvascular thrombosis • extensive alveolar and interstitial inflammation (known as diffuse alveolar damage, DAD) • pulmonary intravascular coagulopathy • ventilation perfusion mismatch • right to left shunt and refractory ARDS.
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  24. 24/34 TYPES OF DIAGNOSTIC TESTS FOR COVID-19 1. Tests to detect the virus 2. Tests to detect antibodies to the virus 3. Antigen detection tests Preferably these samples should be obtained as early as symptom onset, since it yields higher virus concentrations.
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  28. 28/34 Test to detect virus: PCR TEST ▪ Advantages of PCR tests ▪ Highly specific(100% specificity) ▪ Tests becomes positive in the early phase of the disease Disadvantages of PCR tests • Complicated, expensive, and is thus mainly suited to centralized reference laboratories. • Sensitivity may be as low as 50-70%. • Reasons: Number of viral particles may not be large in some infected patients. • PCR can become negative in the later phases of disease as the patients immunity builds up.
  29. 29/34 TESTS TO DETECT ANTIBODIES TO THE VIRUS These are mainly of two types. • ELISA (Enzyme linked immunosorbent assay). • Rapid tests can be done at the point of care without highly trained personal. Two types of antibodies are tested : • IgM antibody which rises first after infection and it is an indicator for an active infection. • IgG type of antibody rises later and is an indicative of past infection.
  30. 30/34 ANTIBODY BASED TESTS Advantages • Used for the rapid screening • Qualitatively detects IgG and IgM Ab • Cheaper & faster results Disadvantages • Negative in the early phase of the disease. IgM titers starts to rise only 3-7 days after the onset of symptoms • The specificity of the test can also be a concern when it is used primarily as a standard diagnostic test.
  31. 31/34 ANTIGEN BASED TESTS Minimum acceptance criteria of sensitivity and specificity of Rapid Ag Test Kits: • Validated as a Point of Care Test (POCT) without transport to a laboratory setupSensitivity: 50% and above; Specificity: 95% and above • Validated in a laboratory setup with samples collected in Viral Transport Medium (VTM)- Sensitivity: 70% and above; Specificity: 99% and above
  32. 32/34 Clinical guidance • Keeps changing • Refer to latest clinical guidance document • Scan this for latest home isolation guidelines
  33. 33/34 Control and disease prevention
  34. 34/34 “Everything we do before a pandemic will seem alarmist. Everything we do after will seem inadequate” ~ Michael Leavitt
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  36. 36/34 Disease prevention and control – clinical settings Most important in clinical settings:- 1. Hand-washing 2. Immunization (If available) 3. Use of PPE 4. Strict compliance to Infection Prevention and Control (IPC) protocols 5. Bio-medical waste management protocol compliance
  37. 37/34 COVID-19 ISOLATION WARDS ▪ Separate colour coded bins/bags/containers in wards and maintain proper segregation of waste as per BMWM Rules and CPCB guidelines –all four categories (yellow, red, white, blue) ▪ Double layered bags (2 bags) used for collection of BMW so as to ensure adequate strength and no-leaks
  38. 38/34 Six steps for hand-washing
  39. 39/34 5 Moments of handwashing
  40. 40/34 Personal Protection Equipments
  41. 41/34 BMW DISPOSAL – YELLOW BAGS ▪ Collect used masks (triple layer mask & N95 mask), head cover/cap, shoe- cover, disposable linen gown, non-plastic or semi-plastic coverall
  42. 42/34 COVID 19 vaccination • Coverage as of today (31-mar-2023) :- • About 104 Crore people have received 1st dose • About 92 Crore people have received 2nd dose Vaccines available:- • Covaxin, Covishield, Corbevax
  43. 43/34 Some MCQs on COVID • Corbevax • Biologicals E. Limited, India produces it • Adolesceents 12-14 years • Receptor binding domain recombinant subunit type of vaccine • 2 doses 0.5 ml i.d 4 weeks apart • Cold Chain 2 – 8 degree • When did vaccinations started in India – 16th Jan 2020 • Duration by which COVID 19 vaccine has to be deferred after recovery from illness – 3 months Which vaccine can be given to lactating mother – COVISHIELD and covaxin both • 2 Deoxy D-Glucose – Emergency Use Authorization – Anti metabolite – suppresses viral multiplication • VIRAFIN – pegylated INF-Alpha 2b for moderate COVID – Increase Antibody production
  44. 44/34 Some MCQs on COVID • BBV-154 – Nasal Vaccine, Viral vector vaccine by bharath biotech • Novovax – spike protein binder (protein sub unit), 2 doses, 3 weeks apart • mRNA – Gennova, moderna , Pfizer • Viral vector based: Astra Zeneca (Covishield), Sputnik V, Gamaleya • Whole virus – Sinovac, Covaxin
  45. 45/34 Some MCQs on COVID • Sputnik V – Powdered form!!! But still has to be stored in 2-8, >=18 years of age, 0.5 ml 3 weeks apart • Sputnik Light – one dose vaccine, 70% Vaccine efficiency • Portals: COWIN, evin, rtPCR, • Minimum gap between covid 19 vaccine: 14 days
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