Protecting Personnel from Pandemic Influenza American Industrial Hygiene Conference and Exposition, Toronto, 2009

1. Protecting Personnel from Pandemic Influenza American Industrial Hygiene Conference and Exposition, Toronto, 2009 John H Murphy BSc MHSc MBA ROH CIH GradIOSH President, Resource Environmental Associates

2. Module 1 Introduction to the Course

3. 1. Introduction to the Course 1.1 Instructor and Class Introductions 1.2 Background to Course Development 1.3 Scope of the Government of Ontario Study 1.4 Types of Work Environments Examined 1.5 Subject Matter of this Course 1.6 Curriculum Overview 1.7 Learning Objectives 1.8 Course Materials 1.9 Housekeeping 1.10 Any Questions?

4. 1.1 Instructor and Class Introductions John H. Murphy President, Resource Environmental Associates Limited • Bachelor of Science, Physiological Psychology and Radiation Biology, University of Toronto, 1984 • Master of Health Science, Occupational & Environmental Health, University of Toronto, 1985 • Post-graduate Studies, Occupational Epidemiology, University of Western Ontario, 1987-88 • Master of Business Administration, University of Toronto, 1993 • Certified Industrial Hygienist (ABIH) • Registered Occupational Hygienist (CRBOH) • Graduate Member, UK Institution of Occupational Safety and Health

5. 1.2 Background to Course Development • In January 2008, the Ontario Ministry of Government and Consumer Services contracted Resource Environmental Associates Limited to conduct a pandemic influenza risk assessment. • The principal goals of the study were: • to rate relative risks in Government of Ontario work settings, and • provide recommendations concerning non-pharmaceutical / environmental infection prevention and control measures, in case of a pandemic influenza outbreak.

6. 1.2 Background to Course Development • “Non-pharmaceutical” or “environmental” infection prevention and control measures = • control measures and procedures, focused on the work environment, building systems, and work processes, intended to protect personnel from potential workplace and work-related exposure to influenza virus, and thereby reduce infection risks. • These types of controls are intended to minimize the transmission of viral material shed from a person to the air, to a surface, or to the skin or clothing of one person to another – in contrast to medically-oriented preventive measures such as immunization or prophylactic drug treatments.

7. 1.2 Background to Course Development • Recommendations were to: • be proportionate to risks • reflect the state of scientific knowledge related to influenza infection prevention and control • Cover preparatory actions to take now, and actions to take if an outbreak occurs • The methods developed in this study, and the recommendations arising, are the basis for this course.

8. 1.3 Scope of the Government of Ontario Study • Sixteen workplace locations across Ontario were examined for the purpose of collecting information on work settings and work activities performed by Government of Ontario personnel. • The workplace locations were pre-determined by the client, with a view to covering a range of different working environments representative of government operations. • Information gathered at these work settings was used for risk assessment and control planning purposes.

9. 1.4 Types of Work Environments Studied

10. 1.5 Subject Matter Covered in this Course • Basic information about influenza pathology and health effects. • Review of the state of science regarding routes by which employees may be exposed to influenza virus in the course of their work, and the relative importance of these exposure routes from a prevention perspective. • The efficacy and practicality of various actions to minimize exposure. • Methods for workplace influenza virus exposure risk assessment. • Recommendations with respect to ways and means of preventing and controlling transmission of influenza in work settings.

11. 1.6 Curriculum Overview Module 1.0 Introduction to the Course Module 2.0 Influenza 101 Module 3.0 Modes of Exposure and Transmission Module 4.0 Occupational Risk Assessment Module 5.0 Influenza Prevention and Control Measures Module 6.0 Preparing for and Responding to an Influenza Pandemic

12. 1.7 Learning Objectives • There are specific learning objectives for each of the 5 course modules that follow this Introduction. • The learning objectives will be presented at the start of each module.

13. 1.8 Course Materials • Detailed course curriculum • Course slides • Instructor resume • List of reference materials (end of course slides)

14. 1.9 Housekeeping • Morning break, lunch, afternoon break • Fire safety • Cellphones / PDAs • Asking questions

15. 1.10 Any Questions?

16. Module 2 Influenza 101

17. 2. Influenza 101 Learning Objectives 2.1 What is Influenza? 2.2 Characteristics of the Virus 2.3 Disease Mechanism 2.4 Infectious Dose 2.5 Comparison with the Common Cold 2.6 Is Influenza a Serious Health Risk? 2.7 What is an Influenza Pandemic? 2.8 Why the Concern over a Possible Influenza Pandemic? 2.9 Could a Influenza Pandemic be Severe? 2.10 What’s the Connection between Avian Influenza and a Human Influenza Pandemic? Questions

18. Learning Objectives 1. Understand the symptoms of influenza. • Understand the sequence of events leading to the disease. • Know how influenza differs from the common cold. • Understand the potential severity of a pandemic influenza, and the basis for these estimates of severity. • Understand the meaning of a “pandemic”. • Understand the role of avian influenza in driving current concern over a potential influenza pandemic.

19. 2.1 What is Influenza? • Influenza (also known as the flu) is a contagious respiratory illness caused by influenza viruses. • Common flu symptoms are: • Fever  (usually high) • Headache • Extreme tiredness • Dry cough • Sore throat • Runny or stuffy nose • Muscle aches • Stomach symptoms, such as nausea, vomiting, and diarrhea, also can occur but are more common in children than adults. • Infection can last from a few days to about 2 weeks.

20. 2.2 Characteristics of the Virus • Influenza viruses range in size from about 20 nanometers (2/100th of a micron, an example being rhinovirus) to 120 nanometers (12/100th of a micron, an example being influenza A virus):

21. 2.3 Disease Mechanism • The disease mechanism involves the following steps: • Delivery of a “critical dose” of the virus to the target tissues in the lungs • Entry of the virus into the cells of the target tissues • Reproduction of the virus inside the target tissue cells, using the biomolecules of the cell as building blocks • Death of the host cells due to depletion of biomolecules and cell rupture caused by the massive quantity of virus particles created inside the cell • Dead cells + cellular contents + white blood cells + blood plasma = fluid in lungs • Significant fluid in lungs results in impaired gas exchange and laboured breathing

22. 2.4 What Constitutes an “Infectious Dose” • A limited amount of data is available on what constitutes an infectious dose in humans. One study estimated the 50% human infectious dose (HID50) for influenza A administered by the aerosol route to be 0.6 to 3 50% tissue culture infectious dose (TCID50) units (Alford 1966). • The TCID50 is a quantitative unit for virus, representing an unknown number of virus particles observed to infect 50% of replicate cell cultures, each receiving the same volume of virus. • Another study estimated the HID50 for a different strain of influenza administered intranasally to be 127 to 320 TCID50 units (Murphy 1973). • Based on the assumption that a TCID50 unit corresponds to more than one virus particle, it has been estimated that 44,000 particles on average are emitted in coughs, although only 0.0001% of these potentially infectious particles remain airborne (Nicas and Sun 2006).

23. 2.5 Comparison with the Common Cold

24. 2.6 Is Influenza a Serious Health Risk? • Influenza can cause mild to severe illness, and can sometimes cause death. • 10% to 20% of the population in western nations contracts “seasonal influenza” in a typical year, and this may result in about 3 deaths in 10,000 cases. • Most infected people recover from seasonal influenza within without requiring medical treatment. • In the very young, the elderly, and those with other serious medical conditions, influenza infection can exacerbate underlying health problems, cause pneumonia, and result in death.

25. 2.7 What is an Influenza Pandemic? • A “pandemic” is an “epidemic” that affects a large geographic region, or even the entire world. • An “epidemic” is an outbreak of disease that: • causes much higher rates of illness than the typical “background rates”; and / or • has more severe health consequences than the usual form of the disease. • The term “influenza pandemic” refers to an outbreak of influenza: • for which there is low human immunity; • that causes more severe illness than is typically associated with influenza (due to limited human immunity); and • affects large geographic regions, or the entire world.

26. 2.8 Why the Concern over a Possible Influenza Pandemic? • There is a recorded history of periodic influenza pandemics. • In the past 120 years, there have been four influenza pandemics: • The “Asiatic Flu", 1889–1890 • The "Spanish Flu", 1918–1919 • The "Asian Flu", 1957–58 • The "Hong Kong Flu", 1968–69 • The absence of an influenza pandemic for 40 years may mean that we are “overdue” for one. • The appearance of human cases of avian influenza has raised concerns that the virus causing avian influenza could eventually spark a human influenza pandemic.

27. The Significance According to Google

28. Indicators of a Growing Concern USA Canada

29. Influenza Pandemics, 1500 to Present • The first recorded pandemic that was likely to have been influenza started in 1510 in Africa, and spread across Europe. • The “Asiatic Flu", 1889–1890. First reported in May of 1889 in Russia. By October, it had reached the Caucasus. It rapidly spread west and hit North America in December 1889, South America in February 1890, India in February 1890, and Australia in March 1890. It had a very high attack and mortality rate. Believed to be caused by the H2N8 type of flu virus. • The "Spanish Flu", 1918–1919. First identified early March 1918 in US troops training in Kansas, by October 1918 it had spread to become a world-wide pandemic on all continents. Unusually deadly and virulent, it ended nearly as quickly as it began, vanishing completely within 18 months. In six months, 25 million were dead. Believed to be caused by the H1N1 virus.

30. Influenza Pandemics, 1500 to Present • The "Asian Flu", 1957–58. First identified in China in late February 1957. Spread to the United States by June 1957. Caused about 70,000 deaths in the United States. Caused by the H2N2 virus. • The "Hong Kong Flu", 1968–69. First detected in Hong Kong in early 1968 and spread to the United States later that year. Caused about 34,000 deaths in the United States. Caused by the H3N2 virus, which still circulates today.

31. More on Influenza Virus Types • There are three types of influenza viruses: A, B and C. Influenza A and B viruses cause seasonal influenza epidemics. Influenza type C infections cause a mild respiratory illness and are not thought to cause epidemics. • Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus: hemaglutinin (H) and neuraminidase (N).

32. Other Events that Have Contributed to the Concern Over a Pandemic 2005 Seven Oaks Legionnaires, Toronto, 21 deaths 1997 – First Human Cases, Avian Flu, Hong Kong, 18 deaths 2001 Anthrax Powder Mail Attacks, USA, 5 deaths 1976 – First Human Cases, Ebola Virus, Zaire, 150 deaths 1975 1980 1985 1990 1995 2000 2005 2010 1995 – “Twelve Monkeys”, Bruce Willis, Terry Gilliam 2003 – SARS, China, Hong Kong, Toronto, 251 deaths 1960s-1970s: “Victory Over Infectious Disease” 1981-83 – First Recognized AIDS Cases, USA 1999 – First Human Cases of West Nile Virus in North America 2004 – ?: Increased Government and Business Activity on Avian Influenza Preparedness

33. 2.9 Could an Influenza Pandemic be Severe? • There is no way of knowing how severe a future influenza pandemic could be. • For pandemic planning purposes, it is often assumed that the attack rate for the type of influenza causing a pandemic would be comparable to, or higher than the attack rate for seasonal influenza – that being 10% to 20%. • The Ontario Health Plan for an Influenza Pandemic projects a worst-case scenario with a 35% attack rate for Ontario, meaning that about 4.5 million people would get sick. The Plan assumes a mortality rate of about 0.1%, which is about 3x the mortality rate for seasonal influenza. This represents about 20,000 deaths.

34. 2.10 What’s the Connection Between Avian Influenza and a Human Influenza Pandemic? • The four influenza pandemics between 1889 and 1968 have been caused by types if “influenza A” viruses. • The avian influenza virus is a type of influenza A virus, called H5N1. • At present, it appears that avian influenza is not easily transmitted from birds to humans, and not transmitted at all between humans. • Between 2003 and March 2009, there were only about 390 confirmed cases of avian influenza, and all with in Asia and North Africa. • However, about 65% of these persons died.

36. WHO: Avian Flu (H5N1) Statistics

37. 2.10 What’s the Connection Between Avian Influenza and a Human Influenza Pandemic? (continuation) • Influenza viruses can readily mutate, which can affect ease of animal-to-human, or human-to-human transmission. • If the H5N1 avian influenza virus mutated in a way that caused easier transmission, it could result epidemics or a pandemic, and given the high mortality rate, there could be many deaths. • However, a human influenza pandemic could also be caused by other types of influenza A viruses.

38. The Antigenic Shift

39. WHO: Swine Flu (H1N1) Statistics • As of May 25, 2009, the World Health Organization reports 12,515 confirmed human cases and a mortality rate of 0.7% (91 deaths). • Observations made by WHO: • Very contagious, attack rate seems to be higher than seasonal influenza, at 22-33% • Outside of Mexico, causes mild illness • Younger population effected • Illness tends to be more severe in those with underlying medical conditions

41. 2. Review - Influenza 101 2.1 What is Influenza? 2.2 Characteristics of the Virus 2.3 Disease Mechanism 2.4 Infectious Dose 2.5 Comparison with the Common Cold 2.6 Is Influenza a Serious Health Risk? 2.7 What is an Influenza Pandemic? 2.8 Why the Concern over a Possible Influenza Pandemic? 2.9 Could a Influenza Pandemic be Severe? 2.10 What’s the Connection between Avian Influenza and a Human Influenza Pandemic?

42. Questions?

43. Module 3 Modes of Exposure and Transmission

44. 3. Modes of Exposure and Transmission Learning Objectives 3.1 When is a Person Infectious? 3.2 Routes of Virus Exposure and Dosing 3.3 Relative Significance of Exposure Routes 3.4 Transmission by Inhalation 3.5 Contact Transmission Questions

45. Learning Objectives 1. Know when a person infected with influenza is contagious. • Understand the theoretical and likely routes of virus entry for disease initiation. • Understand the reasons why inhalation exposure is likely to be a far more significant mode of disease transmission than self-inoculation / contact transmission. • Understand the physical basis for a 2 meter “protective zone” against inhalation exposure to influenza. • Understand why aerosol exposure is likely to be less significant than droplet exposure, and exceptions to this general premise.

46. 3.1 When is a Person Infectious? • Most healthy adults may be able to infect others beginning 1 day before symptoms develop and up to 5 days after becoming sick. • Children may pass the virus for longer than seven days after becoming sick. Symptoms start one to four days after the virus enters the body. • You may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick. • Some persons can be infected with the flu virus but have no symptoms. During this time, those persons can still spread the virus to others.

47. 3.2 Routes of Virus Exposure and Dosing Virus Dose by Inhalation (P) Virus Dose by Inoculation to Mucosa (R) Virus Dose to Target Tissue (U) Risk of Infection Virus Dose by Ingestion (R’) U = ∫{ a[P] + b[R] + c[R'] }

48. 3.2 Routes of Virus Exposure and Dosing Inhalation of Air -Background Viral Concentration Virus Dose by Inhalation (P) Inhalation of Droplets in Discharge Path Virus Dose by Inoculation to Mucosa (R) Virus Dose to Target Tissue (U) Hand to Eye / Nose / Mouth Virus Dose by Ingestion (R’) U = ∫{ a[P] + b[R] + c[R'] }

49. 3.3 Relative Significance of Exposure Routes Virus Dose by Inhalation (P) Virus Dose to Target Tissue (U) Risk of Infection Virus Dose by Inoculation to Mucosa (R) Empirical evidence on influenza, scientific information on virus-host interactions, and exposure dynamics considerations, point to inhalation being the most significant mechanism for transmission of infection Virus Dose by Ingestion (R’) U = ∫{ a[P] + b[R] + c[R'] } Where a >>> b >>> c

50. 3.3 Relative Significance of Exposure Routes • For purposes of this course, we assume that an influenza strain causing a pandemic would likely be transmitted in the same way as seasonal influenza. • The preponderance of evidence suggests that seasonal influenza is spread from person-to-person primarily when a non-infected person inhales viral droplets and droplet nuclei expelled by an infected person through sneezing, coughing or breathing (Tellier 2007). • Therefore, to understand the rationale for, and how to implement measures to minimize risk of infection by inhalation, it is necessary to understand how viruses discharged from an infected person by coughing or sneezing can be inhaled by other persons.