Pandemic and Avian Influenza Bird flu and Beyond. Jonathan Weinstein, MD FAAP

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1 Jonathan Weinstein, MD FAAP

2 Discussion points Pandemic Influenza The flu defined what is pandemic influenza? Influenza A in birds Infection in humans The current outbreak Potential for pandemic Infection Control & Respiratory Isolation

3 Pandemic and Avian Influenza defined

4 What is the flu? flu terms defined Seasonal (common) flu Respiratory illness, may be transmitted person to person Most people have some immunity Vaccine is available Average # fatalities in the United States per year = 30-40,000

5 What is the flu? flu terms defined Avian (bird) flu Caused by influenza viruses found naturally among wild birds H5N1 variant deadly to domestic fowl, can be transmitted from birds to humans No human immunity, no vaccine is available Bird flu = Pandemic flu?

6 What is the flu? flu terms defined Pandemic flu Virulenthuman flu Causes global outbreak (pandemic) of serious illness Little natural immunity Disease can spread easily from person to person Currently, there is no pandemic flu

7 More about Avian Influenza Wild birds worldwide carry viruses in intestines, usually do not get sick Contagious, can make some domesticated birds (chickens, ducks, turkeys) very sick and kill them Two forms, based on virulence Low pathogenic often undetected, usually causes only mild symptoms (e.g. ruffled feathers, egg production) Highly pathogenic more rapid spread, multiorgan infection, mortality to %, often w/in 48 hours

8 More about Avian Influenza Low pathogenic vs. highly pathogenic Difference apparent in birds Effect in humans unknown at this time

9 Influenza A viruses 16 H subtypes, 9 N subtypes Only H5, H7 subtypes known to cause highly pathogenic disease Not all viruses of the H5, H7 subtypes are highly pathogenic, not all will cause severe disease in poultry Which viruses can cause the highly pathogenic form? H5 and H7 viruses typically introduced to poultry in low pathogenic form When allowed to circulate in poultry populations, viruses can mutate into highly pathogenic form, usually within months This is why H5 or H7 virus in poultry is always cause for concern, even when initial signs of infection are mild

10 More about Avian Influenza United States: outbreak of highly pathogenic avian influenza A virus (H5N2) in poultry 16 outbreaks of low pathogenic avian influenza A viruses (H5 and H7 subtype), including

11 More about Avian Influenza H7N2 in New York! November 2003: Patient with serious underlying medical conditions admitted to a New York hospital with respiratory symptoms Initial laboratory tests identified an influenza A virus, thought to be H1N1 Patient recovered, went home after a few weeks Subsequent confirmatory tests confirmed infection with an H7N2 avian influenza A virus

12 So what! So what? H7 more likely to be highly pathogenic Human transmission

13 Avian influenza spread among birds Virus shed in saliva, nasal secretions, and feces Susceptible birds become infected after contact with contaminated excretions, secretions or surfaces Domesticated birds may become infected through direct contact with infected waterfowl, poultry contact with surfaces (such as dirt or cages) contact with materials (such as water or feed)

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15 Human infection

16 Human infection Bird flu viruses usually do not infect humans However, > 200 confirmed cases of human infection with bird flu viruses have occurred since 1997

17 Add current TABLE of cases

18 So how does human infection occur? Most cases: Direct or close contact with infected poultry (e.g., domesticated chicken, ducks, and turkeys) Direct contact with contaminated surfaces Extremely rare: Ill person to another person Transmission not observed continuing

19 Outbreaks: a timeline 1997: H5N1 (Hong Kong) infections with highly pathogenic strain occurred in both poultry and humans First time avian influenza A transmission directly from birds to humans documented 18 hospitalized, six eventually died Infection control authorities killed ~1.5 million chickens to remove source of virus

20 Outbreaks: a timeline : outbreaks in Cambodia, China, Indonesia, Japan, Laos, S. Korea, Thailand and Vietnam > 100 million birds in affected countries either died from disease or destroyed to try to control outbreaks March 2004: under control

21 The outbreak continues June 2004: new H5N1 cases Since then, virus has spread Mid-2005: Europe Early 2006: Africa, Near East Human cases reported in Azerbaijan, Cambodia, China, Egypt, Indonesia, Iraq, Thailand, Turkey and Vietnam

22 Confirmed H5N1 Avian Influenza cases (April 21, 2006)

23 Unique features of current H5N1 outbreak (since 2003) Largestand most severe on record Never before have so many countries been simultaneously affected, or resulted in the loss of so many birds H5N1 virus especially tenacious Endemic in many regions, despite death/destruction of ~ 150 million birds Especially virulent among victims

24 Symptoms in humans Wide range Typical fever, cough, sore throat, muscle aches Localized, systemic conjunctivitis, pneumonia, severe respiratory disease (e.g. ARDS) Other severe, life-threatening complications May depend on virus subtype and strain

25 Implications to humans two main risks Direct infection infected bird to humans Mutation if given enough opportunities, virus may change into a form that is highly infectious for humans, spreads easily

26 Effect of pandemics 1. Rapid, widespread global infection Considered unstoppable in part because infected people can shed virus before symptoms appear 2. Severity of disease, number of deaths highly variable, cannot be known prior to the event Past pandemics: attack rates reached 25-35% Assuming mild disease 2 million to 7.4 million deaths worldwide (projections for more virulent virus much higher) 1918 pandemic killed at least 40 million people, with 2.5% mortality rate in USA

27 Effect of pandemics 3. High susceptibility 4. Health care surge Primary Care, Emergency Departments, Public Health 5. Worker absenteeism law enforcement, transportation, communications

28 Treatment Most Avian flu strains appear resistant to amantadine, rimantadine Oseltamivir, zanamavir probably effective But additional studies needed to demonstrate ongoing effectiveness And further resistance possible, likely

29 Methods of prevention (?) Vaccination? Seasonal vaccines do not protect against avian flu Public PPE? Masks not currently recommended for routine use Avoiding eating poultry? No evidence properly cooked poultry or eggs can be a source of infection 2004: government ban on poultry from countries affected by avian influenza, ban still in place

30 Can we get vaccine produced in time? Currently no commercially available vaccine Development is underway (began April 2005) But Takes time to produce Takes time to test Takes time to distribute Virus susceptibility may change

31 Where we stand the facts Human infection atypical, but >200 cases reported Most resulting from direct/close contact with infected poultry or contaminated surfaces Few cases of human-to-human spread Has not continued beyond one person

32 Remember: 3 conditions for pandemic to start 1. New influenza virus subtype must emerge for which there is little or no human immunity 2. Must infect humans and cause illness 3. Must spread easily and sustainably (continue without interruption) among humans First two conditions met! Third condition has not occurred And that s where we stand

33 Where we may wind up the potential Viruses mutate H5N1 virus could develop ability to infect humans, spread easily from person to person Little or no immune current human protection Influenza pandemic

34 Infection Control Infection Control and Respiratory Isolation

35 Infection Control On everyone s minds Pandemic influenza In a real scenario Unknown agent Unknown transmission Unknown isolation & infection control procedures Even during potential influenza pandemic Novel strain? New infectivity parameters? What to do?

36 Infection Control Standard ( universal ) precautions Gown Gloves Mask What we can discuss: Influenza precautions What we don t know: Pandemic precautions Future situations may vary, new rules may apply

37 Infection Control Points of Discussion Modes of influenza transmission Droplet Contact Airborne Basic Infection Control Principles Isolation Precautions Safe work practices PPE

38 Infection Control Modes of Influenza transmission Influenza highly prevalent & recurrent Nevertheless, most information on person-toperson transmission is Indirect Largely obtained through observations during outbreaks in healthcare facilities & other settings (e.g., cruise ships, airplanes, schools, colleges) Direct scientific information is limited

39 Infection Control Modes of Influenza Transmission However, epidemiology is clear C/W spread through close contact Exposure to large droplets Direct contact Near-range exposure to aerosols Little evidence of airborne transmission over long distances or prolonged periods of time Caveat: for novel/pandemic strain Protocols must be determined at time of pandemic, based upon best available evidence at that time

40 Droplet transmission Infection Control The 5 requirements virus getting in & out Contact of conjunctivae or mucous membranes of nose/mouth Of a susceptible person With large-particle droplets Containing microorganisms Generated from person who has a clinical disease or who is a carrier of the microorganism

41 Droplet transmission Infection Control Droplets generated primarily during Coughing Sneezing Talking Routine, common, typical And during the performance of certain procedures such as suctioning and bronchoscopy

42 Droplet transmission Infection Control Large-particle transmission requires Close contact between source & recipient because Droplets do not remain suspended in the air, generally travel only short distances (about three feet) through the air Special air handling and ventilation not required to prevent droplet transmission

43 Infection Control Contact transmission method #1 Direct-contact transmission also can occur (e.g., by hand contact), one serves as source of microorganisms, other as susceptible host Involves 1. Skin-to-skin contact 2. Physical transfer of microorganisms 3. To susceptible host 4. From infected or colonized person Healthcare examples: turning patients, bathing patients, performing other patient-care activities that require physical contact

44 Infection Control Contact transmission method #2 Indirect-contact transmission = contact of a susceptible host with a contaminated intermediate object, usually inanimate, in patient's environment

45 Infection Control Airborne transmission Dissemination & inhalation of droplet nuclei or particles which contain infectious agent Contribution of airborne transmission to influenza outbreaks is uncertain Insufficient studies as to whether transmission can occur across distances (e.g., ventilation systems) or prolonged residence in air

46 Infection Control Infection Control: Preventing the Spread To prevent all possible modes of transmission, facilities should be prepared to implement Engineering/administrative controls Heightened PPE protocols Universal precautions gloves, gown, mask Hand-washing, respiratory hygiene & cough etiquette Which is the most important?

47 Infection Control Respiratory Hygiene and Cough Etiquette Goal: containment at the source, limit spread from infectious patients Elements include: 1. Educating healthcare workers, patients, visitors

48 Infection Control Respiratory Hygiene and Cough Etiquette Elements include: 2. Language-appropriate signage a) Immediately report symptoms b) Use source control measures (e.g., covering mouth/nose when coughing; applying a mask as tolerated) c) Perform hand hygiene measures d) Maintain spatial separation (ideally at least three feet)

49 Infection Control Hand Hygiene what is it? Washing with either plain or antimicrobial soap and water or use of alcohol-based product that does not require water In the absence of visible soiling, alcohol-based products are preferred over soap and water If hands visibly soiled or contaminated, wash hands with soap Healthcare personnel should perform hand hygiene after removing gloves; between patient contacts; and after removing PPE

50 Infection Control Other Basic Infection Control Measures Limit unnecessary contact Isolate infected persons Limit contact between nonessential personnel and other persons (e.g., visitors) and patients who are ill Promote spatial separation in common areas (i.e., sit or stand as far away as possible - at least three feet) to limit contact between symptomatic and nonsymptomatic persons

51 Infection Control Triage of Symptomatic Persons Facilities/organizations should implement healthcare worker & staff triage Screen all healthcare personnel for influenza-like symptoms before coming on duty Determine fitness-for-duty criteria for employees to return to work, based on clinical symptomology of the pandemic utilizing current recommendations

52 Infection Control Patient Transportation Limit patient movement and transport to medically necessary purposes If transportation is necessary, patients should wear a surgical/procedure mask, if tolerated If patient cannot tolerate mask, contain secretions as practically as possible Sheet or towel loosely over the nose/mouth or head

53 Infection Control Personal Protective Equipment (PPE) Infection control policies and procedures should include measures to protect the healthcare worker from possible exposure and illness Compliance of the healthcare provider to the measures is paramount to preventing transmission and infection and must be emphasized during provider education, monitoring, and follow up

54 Infection Control Gloves Single pair of gloves for contact with blood & body fluids, during any hand contact with respiratory secretions (e.g., providing oral care, handling soiled tissues) Do not wash gloves, remove & dispose after use Perform hand hygiene after removal of gloves Use other barriers when there is only limited contact with patient s respiratory secretions Emphasize patient s hand hygiene, hand awareness

55 Respiratory Protection Infection Control Minimum standard: N-95 facepiece respirator when caring for a suspected or confirmed pandemic influenza patient Anticipate shortages Order adequate supplies Medically clearing, fit-testing, and training potential respirator users in advance

56 Infection Control Gowns Most routine patient interactions do not necessitate use of gowns Consider gown if soiling of personal clothes/uniform with a patient s blood or body fluids, including respiratory secretions is anticipated, e.g. Procedures generating increased small-particle aerosols Activities involving holding the patient close (e.g. restraining a pediatric patient) Other patient care activities with a likelihood of contact or exposure (changing linens, ambulating a patient)

57 Gowns Pandemic and Avian Influenza Infection Control Use a disposable gown Wear once & discard Hand hygiene after removing the gown Infection control policies must include proper donning and doffing procedures Prioritize gown use during shortages

58 Infection Control Eye Protection/Goggles Droplet transmission to the conjunctivae may be possible If sprays or splatter of infectious material is likely, goggles or a face shield should be worn (e.g., when within three feet of a coughing/sneezing influenza patient)

59 Protocols for donning Personal Protective Equipment (PPE)

60 Protocols for removing Personal Protective Equipment (PPE)

61 Infection Control Surprise quiz! What type of PPE would YOU use? Taken from CDC Guidance for the Selection and Use of Personal Protective Equipment (PPE) in Healthcare Settings training Options are Gloves and/or Gowns and/or Mask and goggles or a face shield None

62 Guidance for the Selection and Use of Personal Protective Equipment (PPE) in Healthcare Settings Giving a bed bath? Generally none Suctioning oral secretions? Gloves and mask/goggles or face shield sometimes gown Transporting a patient in a wheel chair? Generally none required Responding to an emergency where blood is spurting? Gloves, fluid-resistant gown, mask/goggles or face shield Drawing blood from a vein? Gloves Cleaning an incontinent patient with diarrhea? Gloves w/wo gown Irrigating a wound? Gloves, gown, mask/ goggles or face shield Taking vital signs? Generally none Remember: options are 1. Gloves 2. Gowns 3. Mask and goggles or a face shield 4. None

63 Avian and Pandemic Influenza Infection Control Major resources Centers for Disease Control World Health Organization

64 Jonathan Weinstein, MD FAAP