infection and control of aerosol transmissable diseases
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Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Infection Control ofInfection Control ofAerosol Transmissible Aerosol Transmissible
DiseasesDiseases
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
The Chain Model of The Chain Model of Communicable DiseasesCommunicable Diseases
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
The Chain Model of The Chain Model of Communicable DiseasesCommunicable Diseases
Infectious agent Infectious agent
Reservoirs and/or sourcesReservoirs and/or sources– humanhuman– animalanimal– EnvironmentEnvironment
Portal(s) of exit:Portal(s) of exit:– Respiratory tractRespiratory tract– GI tractGI tract– Genital/urinary tractGenital/urinary tract– Breaks in skinBreaks in skin
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
The Chain Model of The Chain Model of Communicable DiseasesCommunicable Diseases
Modes of transmissionModes of transmission– Direct contactDirect contact– Indirect contactIndirect contact
Portals of entryPortals of entry
Susceptible hostsSusceptible hosts
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Modes of Transmission Modes of Transmission
Direct TransmissionDirect Transmission– Direct ContactDirect Contact– Droplet Droplet
Indirect TransmissionIndirect Transmission– Vector-borneVector-borne
Vertical transmission (mother to Vertical transmission (mother to infant)infant)
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Infectious AerosolsInfectious Aerosols
Department of Medical Microbiology,Edinburgh University
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Transmission of Infections by Transmission of Infections by Respiratory AerosolsRespiratory Aerosols
• DropletsDroplets: land directly on mucosal lining of nose, : land directly on mucosal lining of nose, mouth, eyes of nearby persons or can be inhaled.mouth, eyes of nearby persons or can be inhaled.
Highest exposures within 3-6 feet.Highest exposures within 3-6 feet.
• AirborneAirborne: aerosols become smaller by evaporation; : aerosols become smaller by evaporation; small aerosols (≤ 10 microns) remain suspended for small aerosols (≤ 10 microns) remain suspended for longer periods, if inhaled travel deep into the lungs. longer periods, if inhaled travel deep into the lungs.
• ContactContact: Aerosols/ secretions contaminate nearby : Aerosols/ secretions contaminate nearby surface. Touch surfaces surface. Touch surfaces can infect self or others.can infect self or others.
Relative contribution of three routes varies with agent.Relative contribution of three routes varies with agent.
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Modes of Transmission viaModes of Transmission viaInfectious Respiratory SecretionsInfectious Respiratory Secretions
Droplet: Droplet: meningococcal meningitis, rubella, meningococcal meningitis, rubella, pertussis, common cold, SARS, influenza*pertussis, common cold, SARS, influenza*
Airborne: Airborne: tuberculosis, measles, varicella, tuberculosis, measles, varicella, smallpox, SARS, avian influenzasmallpox, SARS, avian influenza
Indirect contact: (fomite) Indirect contact: (fomite) RSV, SARSRSV, SARS
*Influenza traditionally droplet, increasing evidence *Influenza traditionally droplet, increasing evidence for airborne componentfor airborne component
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Infection Control in aInfection Control in aHealth Care SettingHealth Care Setting
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Infection Control in a Health Care Infection Control in a Health Care SettingSetting
Basic principlesBasic principles
Standard precautionsStandard precautions
Transmission-based precautionsTransmission-based precautions
Seasonal influenza in health care settingsSeasonal influenza in health care settings
Vaccination of HCWsVaccination of HCWs
TB screening of HCWsTB screening of HCWs
Proper donning and doffingProper donning and doffing
Choose your PPEChoose your PPE
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Basic Principles Basic Principles All body fluids are potentially infectious (except All body fluids are potentially infectious (except
sweat) sweat) – blood and blood-tinged fluids including open-blood and blood-tinged fluids including open-
woundswounds– stool, urine, vomit, respiratory secretions, stool, urine, vomit, respiratory secretions,
saliva, semen, vaginal secretions, breast milk, saliva, semen, vaginal secretions, breast milk, other body fluids such as pericardial and other body fluids such as pericardial and synovial fluidssynovial fluids
Minimize exposure to potentially infectious body Minimize exposure to potentially infectious body fluidsfluids
Infection control measures designed to “break the Infection control measures designed to “break the chain” of transmissionchain” of transmission
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Standard Precautions in Health Standard Precautions in Health Care SettingsCare Settings
1.1. Appropriate hand hygieneAppropriate hand hygiene2.2. Barrier protective equipment:Barrier protective equipment:
– if splash, splatter, or sprays can be if splash, splatter, or sprays can be reasonably anticipatedreasonably anticipated
– choose appropriate PPE as needed: choose appropriate PPE as needed: gloves, gown, mask, eye protection gloves, gown, mask, eye protection (face shield, goggles)(face shield, goggles)
3.3. Proper use and handling of Proper use and handling of patient care equipmentpatient care equipment
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Standard Precautions in Health Standard Precautions in Health Care SettingsCare Settings
4.4. Proper environmental cleaning and Proper environmental cleaning and disinfectiondisinfection
5.5. Proper Handling of LinenProper Handling of Linen6.6. Adherence to Bloodborne Pathogens Adherence to Bloodborne Pathogens
StandardsStandards7.7. Proper patient placement Proper patient placement 8.8. Respiratory Hygiene/Cough EtiquetteRespiratory Hygiene/Cough Etiquette9.9. Safe injection practicesSafe injection practices
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Expanded Isolation Precautions:Expanded Isolation Precautions:Transmission-based Standards Transmission-based Standards
When standard precautions are When standard precautions are not enoughnot enough
Additional measures based on Additional measures based on mode of transmissionmode of transmission Contact Precautions Contact Precautions Droplet PrecautionsDroplet Precautions Airborne PrecautionsAirborne Precautions
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Transmission-Based Precautions: Transmission-Based Precautions: Contact PrecautionsContact Precautions
For known or suspected infections For known or suspected infections that represent an increased risk of that represent an increased risk of spread by direct or indirect spread by direct or indirect contact with the patient or the contact with the patient or the patient’s environmentpatient’s environment
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Transmission-Based Precautions: Transmission-Based Precautions: Contact Precautions Contact Precautions
Personal Protective Equipment Personal Protective Equipment Gown & Gloves for all patient interactionsGown & Gloves for all patient interactions Don PPE on entry, discard before exiting Don PPE on entry, discard before exiting
room.room. (in addition to Standard (in addition to Standard Precautions)Precautions)
Examples: MRSA, Examples: MRSA, C difficileC difficile, Norovirus, other , Norovirus, other GI pathogens, RSV, antibiotic-resistant GI pathogens, RSV, antibiotic-resistant
pathogenspathogens
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Transmission-Based Precautions: Transmission-Based Precautions: Droplet PrecautionsDroplet Precautions
Single room preferred, no special ventilationSingle room preferred, no special ventilation Patient: Mask if transport necessary. Instruct Patient: Mask if transport necessary. Instruct
on respiratory hygiene/cough etiquetteon respiratory hygiene/cough etiquette HCWs wear surgical or procedure mask within HCWs wear surgical or procedure mask within
6 feet of patient. Eye protection if splash, spray 6 feet of patient. Eye protection if splash, spray
anticipated anticipated
(in addition to Standard Precautions)
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Transmission-Based Precautions: Transmission-Based Precautions: Airborne Precautions Airborne Precautions
Airborne Infection Isolation Room (AIIR) if availableAirborne Infection Isolation Room (AIIR) if available
Patient: Mask if transport necessary (as tolerated). Patient: Mask if transport necessary (as tolerated).
Health care workers (HCWs):Health care workers (HCWs):
N95 respirator N95 respirator priorprior to entry into room, discarded to entry into room, discarded afterafter exit. exit. Higher level respirators for aerosol-gen procedure. Careful Higher level respirators for aerosol-gen procedure. Careful
attention to proper putting on & taking off (don/doff) attention to proper putting on & taking off (don/doff)
respirator, including seal check.respirator, including seal check. Hand hygiene Hand hygiene before & afterbefore & after don/doff.don/doff. Alert others if need to transferAlert others if need to transfer
(in addition to Standard Precautions)
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Seasonal Influenza in Healthcare Seasonal Influenza in Healthcare Settings: Isolation PrecautionsSettings: Isolation Precautions
For aerosol-generating procedures: For aerosol-generating procedures: N95 respirator N95 respirator + standard + standard precautions (gown, gloves, goggles precautions (gown, gloves, goggles for spray/splash)for spray/splash)
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Vaccination of HCWs Vaccination of HCWs
Protect patients, protect yourself and other HCWsProtect patients, protect yourself and other HCWs CDC recommends CDC recommends
– Measles, mumps, rubella (MMR): vaccinate unless Measles, mumps, rubella (MMR): vaccinate unless documentation of immunity or previous documentation of immunity or previous vaccinationvaccination
– Varicella (chicken pox): vaccinate unless Varicella (chicken pox): vaccinate unless documentation of immunity or previous documentation of immunity or previous vaccinationvaccination
– TdapTdap
– Yearly influenza vaccinationYearly influenza vaccination
– Hepatitis B: vaccinate unless documentation of Hepatitis B: vaccinate unless documentation of previous vaccinationprevious vaccination
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Tuberculosis ScreeningTuberculosis Screeningfor Health Care Workersfor Health Care Workers
TB screening at hire and then TB screening at hire and then annually for all licensed healthcare annually for all licensed healthcare facilities (e.g., acute care hospitals, facilities (e.g., acute care hospitals, skilled nursing facilities, primary skilled nursing facilities, primary care clinics)care clinics)
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Sequence for Donning PPESequence for Donning PPE
1.1. GownGown
2.2. Mask or RespiratorMask or Respirator
www.cdc.gov/ncidod/dhqp/ppe.html
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Sequence for Donning PPESequence for Donning PPE
3.3. Goggles/Face ShieldGoggles/Face Shield
4.4. GlovesGloves
www.cdc.gov/ncidod/dhqp/ppe.html
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Sequence for Removal of PPESequence for Removal of PPE
1.1. GlovesGloves
www.cdc.gov/ncidod/dhqp/ppe.html
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Sequence for Removal of PPESequence for Removal of PPE
2.2. Goggles/Face ShieldGoggles/Face Shield
www.cdc.gov/ncidod/dhqp/ppe.html
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Sequence for Removal of PPESequence for Removal of PPE
3.3. GownGown
www.cdc.gov/ncidod/dhqp/ppe.html
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Sequence for Removal of PPESequence for Removal of PPE
4.4. Mask or RespiratorMask or Respirator
www.cdc.gov/ncidod/dhqp/ppe.html
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
What Type of PPE Would You What Type of PPE Would You Wear?Wear?
Giving a bed bath?Giving a bed bath?– Generally noneGenerally none
Suctioning oral secretions?Suctioning oral secretions?– Gloves and mask/goggles or a face Gloves and mask/goggles or a face
shield – sometimes gownshield – sometimes gown
www.cdc.gov/ncidod/dhqp/ppe.html
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
What Type of PPE Would You What Type of PPE Would You Wear?Wear?
Transporting a patient in a wheel Transporting a patient in a wheel chair?chair?– Generally none requiredGenerally none required
Responding to an emergency where Responding to an emergency where blood is spurting?blood is spurting?– Gloves, fluid-resistant gown, Gloves, fluid-resistant gown,
mask/goggles mask/goggles
www.cdc.gov/ncidod/dhqp/ppe.html
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
What Type of PPE Would You What Type of PPE Would You Wear?Wear?
Taking vital signsTaking vital signs– Generally noneGenerally none
Drawing blood from a vein?Drawing blood from a vein?– Gloves Gloves
www.cdc.gov/ncidod/dhqp/ppe.html
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
What Type of PPE Would You What Type of PPE Would You Wear?Wear?
Cleaning an incontinent patient with Cleaning an incontinent patient with diarrhea?diarrhea?– Gown, glovesGown, gloves
Taking vitals on a patient with Taking vitals on a patient with suspect TB?suspect TB?– N95 respiratorN95 respirator
www.cdc.gov/ncidod/dhqp/ppe.html
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Controlling the Spread of Controlling the Spread of Aerosol Transmissible Aerosol Transmissible
Diseases in Health Care Diseases in Health Care SettingsSettings
Breaking the ChainBreaking the Chain
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Aerosol Transmissible Diseases in Aerosol Transmissible Diseases in Health Care and Public Safety SettingsHealth Care and Public Safety Settings
DropletDroplet– Meningococcal Meningococcal
meningitismeningitis– PertussisPertussis– MumpsMumps– Rubella (German Rubella (German
measles)measles)– Strep pharyngitisStrep pharyngitis– InfluenzaInfluenza
AirborneAirborne– TuberculosisTuberculosis– Varicella Varicella
(chickenpox)(chickenpox)– MeaslesMeasles– SARSSARS– Avian influenzaAvian influenza– SmallpoxSmallpox– InfluenzaInfluenza
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Hierarchy of Infection Prevention and Hierarchy of Infection Prevention and Control MeasuresControl Measures
PPE
Engineering Controls
Protects only the wearer
Elimination of Potential Exposures
Administrative Controls
Protects most
people
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Hierarchy of Control TechnologiesHierarchy of Control Technologies
• Goal is to reduce exposures to a hazardGoal is to reduce exposures to a hazard
Order in which these elements are Order in which these elements are selected to control exposure is selected to control exposure is importantimportant
– Elimination of Potential ExposuresElimination of Potential Exposures– Engineering controlsEngineering controls– Administrative and work practice controlsAdministrative and work practice controls– Personal protective equipment/apparelPersonal protective equipment/apparel
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Elimination of Potential Elimination of Potential ExposuresExposures
• Example: patients with mild influenza Example: patients with mild influenza like illness stay homelike illness stay home
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Engineering ControlsEngineering Controls
Physically separates the employee Physically separates the employee from the hazardfrom the hazard
Does not require employee Does not require employee compliance to be effectivecompliance to be effective
Examples:Examples:– physical barriers at triagephysical barriers at triage– airborne infection isolation room for airborne infection isolation room for
patients with known or suspect airborne patients with known or suspect airborne infectious diseasesinfectious diseases
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Administrative Controls/ Administrative Controls/ Workplace PracticesWorkplace Practices
Policies, procedures, and programs that minimize Policies, procedures, and programs that minimize intensity or duration of exposureintensity or duration of exposure– Examples: Examples:
signs on door of an airborne isolation roomsigns on door of an airborne isolation roomtriage, mask symptomatic patienttriage, mask symptomatic patientprovide tissues/ masks/hand sanitizer to provide tissues/ masks/hand sanitizer to
publicpublic Standard procedures/ behaviors in caring for Standard procedures/ behaviors in caring for
patients e.g. hand hygiene, HCW vaccinationpatients e.g. hand hygiene, HCW vaccination Only as good as enforcementOnly as good as enforcement
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Personal Protective EquipmentPersonal Protective Equipment
Lowest level of hierarchy - requires Lowest level of hierarchy - requires employee compliance for efficacyemployee compliance for efficacy
Means higher elements of hierarchy Means higher elements of hierarchy fail to adequately protect employeefail to adequately protect employee
May involve use of gowns, gloves, May involve use of gowns, gloves, eye/splash protection or respiratorseye/splash protection or respirators
Last line of defenseLast line of defense
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Face Masks vs. N95 RespiratorsFace Masks vs. N95 Respirators Loose fitting, not designed to Loose fitting, not designed to
filter out small aerosols filter out small aerosols Place on coughing patient Place on coughing patient
(source control)(source control) HCW should wear mask toHCW should wear mask to
– protect patient during protect patient during certain procedures (e.g., certain procedures (e.g., surgery, LP) surgery, LP)
– protect HCWprotect HCW droplet precautionsdroplet precautions Mask + goggles for Mask + goggles for
anticipated anticipated spray/splash spray/splash
Tight fitting respirator, Tight fitting respirator, designed to filter the airdesigned to filter the air
Protects the wearerProtects the wearer
HCW should wear when HCW should wear when concerned about concerned about transmission by airborne transmission by airborne routeroute
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Aerosol-Generating ProceduresAerosol-Generating Procedures
Sputum induction, bronchoscopy, Sputum induction, bronchoscopy, elective intubation and extubation, elective intubation and extubation, autopsiesautopsies
CPR emergent intubation, open CPR emergent intubation, open suctioning of airwayssuctioning of airways
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Aerosol Transmissible DiseasesAerosol Transmissible DiseasesBreaking the ChainBreaking the Chain
Source controlSource control– stay home, isolate or separate mask stay home, isolate or separate mask
patientpatient Respiratory hygiene, cough etiquetteRespiratory hygiene, cough etiquette Hand hygieneHand hygiene HCW protectionHCW protection
• VaccinateVaccinate• Droplet – MaskDroplet – Mask• Airborne- N95 respiratorAirborne- N95 respirator
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Questions?Questions?
Dr. Ashish V. JawarkarDr. Ashish V. Jawarkar
Questions?Questions?
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