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Primer on Airborne Isolation: Tuberculosis 101 Jane M. Gould, M.D. Public Health Physician Consultant Bureau of Epidemiology HAIP/AS Program APIC East Central Pennsylvania Chapter Meeting May 13, 2019. Disclosures.
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Primer on Airborne Isolation: Tuberculosis 101 Jane M. Gould, M.D. Public Health Physician Consultant Bureau of Epidemiology HAIP/AS Program APIC East Central Pennsylvania Chapter Meeting May 13, 2019
Disclosures • My husband works for Incyte, but I will not be speaking about any Incyte products • No other disclosures
Abbreviations AFB- Acid Fast Bacilli AI- Airborne Isolation AIIR- Airborne Infection Isolation Room DOT- Direct Observed Therapy HCP- Healthcare provider HEPA- High-Efficiency Particulate Air filter IGRA- Interferon Gamma Release Assay LTBI- Latent Tuberculosis Infection OSHA- Occupational Safety & Health Administration NIOSH- National Institute for Occupational Safety & Health PAPR- Powered Air-Purifying Respirator TB- Tuberculosis TST- Tuberculin Skin Test UVGI- Ultraviolet Germicidal Irradiation
Objectives • Definition of airborne isolation • Pathogens that require airborne isolation • Tuberculosis (TB) 101 • TB Infection Control program • TB Public Health Response
Airborne Precautions • Prevents disease transmitted by aerosols containing droplet nuclei or contaminated dust particles • Droplet nuclei less than 5 µm in size, may remain suspended in air allowing them to migrate for long periods of time • Airborne transmission: • Obligate • Preferential or • Opportunistic
Aerosol Transmission Types • Obligate: transmitted exclusively via fine particle aerosol- ex. TB • Preferential: not exclusively airborne-ex. rubeola (measles) and varicella • Opportunistic: usually transmitted by other routes, but under special circumstances may be transmitted by airborne- ex. smallpox, SARS-associated coronavirus, influenza, norovirus
Airborne Isolation (AI) • Room- AIIR, negative pressure, single patient room, air exhausted to outside (single pass ventilation) or through HEPA filters, door must remain closed • At least 6 air exchanges per hour • Preferably 12 air exchanges per hour • Respirator masks- N-95 fit tested mask or portable respirator for those entering room, standard surgical mask on patient if essential transport out of room is required
OSHA Respirator Requirements Four Performance Criteria • Filters 1-µm particles with efficiency of at least 95% • Fits different facial sizes and characteristics • Can be fit tested to obtain a leakage rate of less than 10% • Can be checked for fit each time a HCP puts on a mask Annual fit testing required by OSHA
Respirator Mask Certification • Respirator masks are certified by NIOSH as meeting the N-95 standard (filters 95% of airborne particles) List of NIOSH approved particulate filtering facepiece respirator masks (N95, surgical N95) www.cdc.gov/niosh/npptl
Empiric Use of AI • Consider with HIV infected persons with cough, fever and unexplained pulmonary infiltrates in any location until tuberculosis can be ruled out • Vesicular rash • MP rash with cough, coryza and fever • Cough, fever, upper lobe pulmonary infiltrates • Cough, fever, any pulmonary infiltrates and recent travel to countries with outbreaks of SARs or avian influenza
Pathogens Requiring AI • Measles • Monkeypox • TB, pulmonary, laryngeal or tracheal • SARS • Smallpox • Zoster, disseminated or in an immunocompromised patient until dissemination ruled out • Pandemic influenza, avian influenza
AI Precautions • If patient has suspected or confirmed measles, varicella or disseminated zoster, nonimmune HCPs should not enter the room • If nonimmune HCP must enter room then they should wear a respirator mask • For immune HCPs no clear guidelines Some facilities require all HCPs entering any AIIR to wear a respirator for sake of consistency
Suspected or Confirmed TB • Patients with suspected or confirmed TB should cover their mouth and nose with a tissue when coughing or sneezing, wear surgical mask for transport • Those with suspected TB should remain in isolation until TB can be ruled out • Confirmed TB on effective anti-TB treatment can be moved out of AI when: • improving clinically and • when 3 consecutive sputum smears collected at least 8 hours apart have no detectable AFB
TB • Mycobacterium tuberculosis complex (n=9 species) • M. tuberculosis • M. bovis • M. africanum • M. canetti • M. caprae- livestock, deer • M. microti- rodents such as voles, mice, shrews • M. pinnipedii- primarily seals • M. mungi- banded mongoose • M. suricattae- meerkats • Acid fast bacillus • Slow growing organism • Increasing rates of antibiotic resistance
TB Transmission • Airborne transmission- inhalation of droplet nuclei • Coughing • Talking • Singing • Congenital transmission from mother to fetus • Organ transplantation- lungs, kidneys, other solid organs • M. bovisis transmitted most often by unpasteurized dairy products, rarely airborne
Risk for TB • Close contacts of a contagious case • Case rates higher in urban, low income areas and in nonwhite racial and ethnic groups • >80% of U.S cases occur in Hispanic and non-white persons • >65% of U.S cases have occurred in non-U.S. born persons • 80% of childhood TB associated with some form of foreign contact of the child, parent or household member • Higher risk: diabetes, substance abuse, homeless, residents of correctional facilities and other congregate settings, immunocompromised • Recent infection within past 2 years
BCG Vaccine: Myths & Facts Used in countries with incidence Given within 1st month of life Vaccine efficacy: www.bcgatlas.org meningitis, miliary/disseminated disease……...85-90% pulmonary disease (18mo after imm)…………….30-40% Most studies from countries with increased incidence Few studies from countries with decreased incidence BCG does not provide lifelong immunity…effectiveness wanes > 50% of infants who received BCG at birth will have a non-reactive TST at 9-12 months of age, majority will be negative by 5 years of age CDC & AAP: DISREGARD BCG Hx for TST interpretation
TB Definitions • TB Exposed: • Child <5 yo or immunocompromised who has been exposed to a communicable TB case • Testing is negative and patient is asymptomatic • Latent TB Infection (LTBI): The Rule • Mycobacterium tuberculosis complex infection in a person • Positive TST or IGRA • No physical findings of disease • Chest radiograph findings: • Normal • Evidence of healed infection (calcification in lung, hilar node) • TB Disease: The Exception • Patient is symptomatic • Pulmonary and/or extrapulmonary disease • Contagious TB
Latent Tuberculosis Infection (LTBI) • Global Epidemiology: • Estimated 1.7 billion people worldwide are currently infected • Potential to develop disease- highest risk in first 2 years after acquisition of infection • U.S. Epidemiology: CDC estimates 90% of TB cases result from reactivation of LTBI Healthy adult: 5-10% Lifetime risk of progression to TB disease Older children & adolescents: 10-15% 1-2 years old: 25% < 12 months: 40% • ~13 million LTBI in U.S. • 550,00-1,100,000 persons will develop active TB over a lifetime if not treated for LTBI
Current National TB Epidemiology 2017: 9,093=2.8/100,000 2018: 9,029=2.8/100,000 www.cdc.gov
TB Case Rates* by Age Group, United States, 1993–2017 Age (yrs.) Cases per 100,000 population *Cases per 100,000 population www.cdc.gov
TB Cases and Rates Among U.S.-Born versus Non-U.S.–Born Persons, United States, 1993–2017 No. of cases Cases per 100,000 Population www.cdc.gov
Percentage of Non-U.S.–Born Persons with TB,by Time of Residence in U.S. Before Diagnosis, 2017 Percentage Top 3 countries of birth: Mexico, Philippines, India www.cdc.gov
TB Morbidity in Pennsylvania 2018-212 TB cases TB Control Program Pennsylvania Department of Health
TB Disease Morbidity in Pennsylvania Case Count Philadelphia 2017-75 2018-78 TB Control Program Pennsylvania Department of Health
Healthcare Associated TB • Inefficient Infection Control Procedures • Delayed suspicion and diagnosis • Clustering of patients who have unsuspected TB with susceptible immunocompromised patients • Delayed recognition of TB in HIV-infected patients because of atypical presentation or low clinical suspicion, leading to misdiagnosis • Failure to recognize and isolate patients with active pulmonary TB • Failure to recognize ongoing infectiousness of patients Blumberg H. Practical Healthcare Epidemiology 4th edition
Healthcare Associated TB • Laboratory delays in identification and susceptibility testing of M. tuberculosis isolates • Delayed initiation of effective anti-TB medications • Inadequate airborne isolation • Lack of AIIRs • Recirculation of air from airborne isolation rooms to other parts of the hospital Blumberg H. Practical Healthcare Epidemiology 4th edition
TB Infection Control Program • Administrative Measures • Environmental Controls • Respiratory Protective Equipment www.cdc.gov
TB Infection Control Program Administrative Measures: Most important • Assignment of responsibility • Expertise or access to expertise in areas • Infection control and healthcare epidemiology • Public health • Occupational health • Engineering • Clinical microbiology • Develop TB IC policies based on annual facility TB risk assessment • Testing and evaluating workers who are at risk for exposure to TB- TST or IGRA • Educate about TB and respiratory etiquette • Ensure proper cleaning of endoscopes www.cdc.gov
TB Infection Control Program Environmental Controls: • Primary- controlling the source • Local exhaust ventilation(hoods, tents or booths) • Diluting and removing contaminated air by using general ventilation • Secondary- controlling air flow • Areas adjacent to AII rooms • Use of HEPA filtration • UVGI www.cdc.gov
TB Infection Control Program Respiratory Protective Equipment: • Third level of hierarchy • Further reduces risk • Training healthcare providers on respiratory protection • Proper use of respirator masks • Annual fit testing • Perform hand hygiene, donning with seal check • Doffing with head tilt forward, discard mask outside of room, perform hand hygiene • Cough etiquette procedures www.cdc.gov
Facility TB Risk Assessment Assess: • Incidence of TB in the community- State or local TB Control program can assist • The number of patients with TB presenting for care at the healthcare facility • Check facility IC database, microbiology laboratory database, medical records database • Timeliness of the recognition, isolation and evaluation of patients with suspect or confirmed TB • Evidence of transmission in facility www.cdc.gov
Facility TB Risk Assessment • Low, medium and ongoing transmission facilities • Evidence of ongoing transmission- immediate investigation with corrective actions, consultation with public health department • Evidence of potential ongoing transmission- clusters or increased rates of HCP test • conversions, HCP with suspect TB disease, • other patients with suspect TB disease
Good Communication is Key • Pennsylvania State law to report suspect or confirmed TB disease within 5 days to local TB Control program in your jurisdiction • Notify prior to hospital discharge • Public Health Department Response: • Case registration • Clinic appointment scheduled • Plan for administration of medication to ensure compliance- utilizing field staff (disease surveillance investigator) • D.O.T= direct observed therapy for TBD • D.O.P.T= direct observed preventative therapy for LTBI • Perform contact investigations • Track all TBD patients in jurisdiction, look for trends in data over time
Typical Public Health Response • Conduct patient, face to face assessments • within 2 business days of assignment for pulmonary cases, suspects, pediatric cases and anyone on home DOT • within 3 business days for extra-pulmonary cases • Establishes the relationship with patient • Interview gathers information not typically captured in the initial report (employment, school and places visited) • Contact assessment is conducted (information on household members, family and friends is obtained to identify persons at risk) • Patient is educated on post-discharge care including D.O.T, patient signs compliance agreement (vary by jurisdiction) • If healthcare exposures have occurred TB Control will help with planning and implementing facility response TB Control Program, Philadelphia Department of Public Health
Summary • Ensuring adequate airborne isolation is vital to preventing transmission of airborne pathogens • Undiagnosed tuberculosis disease is a major risk to your facility • Ensuring excellence in your TB Infection Control program will decrease risk • Maintaining good communication with local and State health departments will decrease risk
Thank You! Contact the DOH HAIP/AS Program at RA-DHHAI@pa.gov717-425-5422