Influenza Pandemic H1N1 2009

Meeting with North West Regional College

Sept 1, 2009

Dr. Brenda Cholin

Outline of today’s discussions

• Background re influenza viruses

• Pandemic history

• Recent events– SARS

– H5N1 Avian flu

– H1N1 influenza virus (human swine flu)

• Pandemic influenza impact

• Limiting spread of influenza

• Preparations for the pandemic

Influenza Viruses

• cause respiratory disease

• 3 types of influenza viruses: Type A - infect humans & birds & other mammals

(birds are the intermediate host)

Type B - only infect humans (no intermediate host)

Type C – infects humans and pigs

• Seasonal (or common) flu is a respiratory illness of humans that can be transmitted person to person. Most people have some immunity, and a vaccine is available.

• Pandemic flu is virulent human flu that causes a global outbreak, or pandemic, of serious illness. Because there is little natural immunity, the disease can spread easily from person to person.

• Swine flu is a respiratory disease of pigs caused by type A influenza viruses. Outbreaks occur regularly in pigs. People do not normally get swine flu, but human infections can and do happen.

• Avian flu (AI) or Bird flu is caused by influenza A viruses that occur naturally among birds. Outbreaks occur regularly in wild and domestic birds. People do not normally get avian flu, but human infections can and do happen.

ReassortmentReassortmentvirusvirusInfluenza A viruses from birds or pigs may undergo

changes through genetic mutation or reassortment with human influenza with potential to create a

human pandemic influenza virus.

Potential Sources of Pandemic Influenza Virus

Non-human Non-human VVirus in bird irus in bird or pigor pig

DIRECTDIRECT

Pandemic Influenza

• First described by Hippocrates in 412 BC

• First documented pandemic occurred in 1580

• Between 1580 and 1900 there were 28 pandemics.

• In last century……

Each Pandemic is Different

H1N1 H2N2

H3N2

1918: “Spanish Flu”

1957: “Asian Flu”

1968: “Hong Kong Flu”

40-50 million deaths

1 million deaths

1 million deaths

Credit: US National Museum of Health and Medicine

Source: WHO

Since the last pandemic…..

• 1976/7 -   Swine Flu– Reappearance of 1950 strain

• SARS– Respiratory disease in humans caused by the SARS-

Coronavirus of animal origin.

– In a matter of weeks, SARS spread from Guangdong province of China to 26 countries around the world

– Between November 2002-July 2003 there were 8,096 known infected cases with 774 deaths (WHO Oct 2004)

AVIAN FLU H5N1

• 1997 – The first time an avian influenza virus was found to be

transmitted directly from birds to people, with infections linked to exposure to poultry markets.

– Eighteen people in Hong Kong were hospitalized, six died.

• 2003 to present – reemergence of H5N1 avian flu with spread among

birds in Asia, Europe and Africa.– 440 humans cases with 262 deaths (Aug 31 2009)– Number of human cases declining since 2006

2009 H1N1 Human pandemic influenza

• A new human influenza virus • Has swine, avian and human genetic elements

which had been seen before• Also has novel swine elements from Eurasia

• First detected in April in 2 children in the USA, then in Mexico

Situation re H1N1 influenza Aug 28, 2009 WHO

• H1N1 pandemic virus is now the dominant influenza strain in most parts of the world. The pandemic will persist in the coming months as the virus continues to move through susceptible populations.

• No signs that the virus has mutated to a more virulent or lethal form.

• Clinical picture: – mild illness in the vast majority of patients– although the virus can cause very severe and fatal illness, also

in young and healthy people, the number of such cases remains small

H1N1 pandemic influenza

• Compared to seasonal influenza, where around 90% of severe and fatal cases occur in people 65 years of age or older…..

• The age groups affected by the pandemic are generally younger. – most frequently infected, – most severe cases and deaths have occurred

in adults under the age of 50 years, with deaths in the elderly comparatively rare.

Vulnerable groups

Increased risk of severe and fatal illness:

• certain medical conditions including respiratory disease, asthma, cardiovascular disease, diabetes and immunosuppression.

• pregnancy

• obesity

• minority groups and indigenous populations…. possible explanations include lower standards of living and poor overall health status, including a high prevalence of conditions such as asthma, diabetes and hypertension.

Impact of pandemic

• Large numbers of people in all countries remain susceptible to infection. Even if the current pattern of usually mild illness continues, the impact of the pandemic during the second wave could worsen as larger numbers of people become infected.

• Larger numbers of severely ill patients requiring intensive care – could overwhelm intensive care units – possibly disrupt the provision of care for other diseases.

• The same virus that causes manageable disruption in affluent countries could have a devastating impact in many parts of the developing world.

Impact of pandemic

• Large numbers of people in all countries remain susceptible to infection. Older people appear to be less likely to become infected – possible due to immunity from infection with a similar virus before 1950

• Even if the current pattern of usually mild illness continues, the impact of the pandemic during the second wave could worsen as larger numbers of people become infected.

• Larger numbers of severely ill patients requiring intensive care – could overwhelm intensive care units – possibly disrupt the provision of care for other diseases.

• The same virus that causes manageable disruption in affluent countries could have a devastating impact in many parts of the developing world.

Pandemic Preparations

• World Health Organization (WHO)– Monitors virus activity around the world– 6 phases – currently in phase 6

• Canada– International response such as travel advisories– Vaccine procurement– Antiviral stockpile– National guidelines for provinces and territories about

management

Saskatchewan’s Preparation

• SK Health lead agency with interaction with other government departments and health regions

• 5 Key areas in SK and RHA pandemic plans:– Surveillance – Immunization – Health services – Communications– Emergency preparedness – stockpiling, emergency ops

Estimating Impact in Canada

Planning Assumptions: moderately severe

• 20-30% of population will not become infected

• >70% of population will become infected – ~ 35% if become ill, illness will be relatively mild

– ~ 35% will become infected and clinically ill • defined as unable to work or do other activities for at least half a day

50% of the clinically ill will seek medical care1% of the clinically ill seeking care will be hospitalized0.4% of the clinically ill will die

Estimated Impact in Saskatchewan

• Total population 1 million• 35% attack rate (moderately severe)• 2 waves, each 6-8 weeks long

350,000 ill people 175,000 extra outpatient visits 4,500 extra hospitalizations 1,400 extra deaths

Limiting the spread of influenza

What is influenza?

• Influenza (the flu) is a respiratory illness

• Usually begins suddenly with fever and cough

• And one or more of the following: sore throat, muscle aches, joint pain, or weakness.

• Vomiting/diarrhea may be present and fever may not be prominent

• Generally lasts about 7-10 days although the cough and fatigue may persist longer.

Contagious period

• Transmission is most likely to occur during the first few days of obvious illness. (1 day before to up to 7 days after onset of symptoms)

• Persons who are ill with ILI symptoms should stay home from work or school, limit contact with others and not return to routine activities outside the home until they are symptom-free or for 7 days, whichever is shorter.

How does influenza spread?

• Flu viruses are spread mainly from person to person through coughing or sneezing of people with influenza.

• Sometimes people become infected by touching something with flu viruses on it and then touch their mouth or nose

Effective measures everyone can take…..

Hand Hygiene

• Wash your hands frequently or• Use alcohol based hand sanitizer

Respiratory Hygiene

• Cover your mouth/nose when you cough/sneeze

Social distancing

• Stay home when you are ill• Avoid close contact with people who

are ill

Washing your hands effectively with soap and water

• Wet hands first with water

• Apply soap to hands

• Rub hands together for at least 15 seconds

• Cover all surfaces of the hands and fingers

• Rinse hands with water and dry thoroughly

• Use paper towel to turn off water faucet

Sneeze and cough into your elbow or sleeve, or use a tissue.   

Cover your cough and sneeze

After wiping or blowing your nose with a tissue, throw away the tissue and wash your hands.

Keep your fingers away from your eyes, nose and mouth

Vaccine

• Vaccine preparation takes about 6 months• Work is well underway on developing a vaccine

for H1N1 influenza • Some countries have started clinical trials.• Canada’s vaccine is expected to be ready in

November.• Will only be used if studies indicate it is safe and

effective and the severity of the pandemic indicates a vaccine is needed

• Will be given separately from seasonal influenza vaccine

Antiviral Medications

• Healthy patients with uncomplicated illness need not be treated with antivirals. – most patients infected with the pandemic virus experience

typical influenza symptoms and fully recover within a week, without any form of medical treatment.

• Will be used to treat people who initially present with severe illness or whose condition begins to deteriorate, and for patients with underlying medical conditions that increase the risk of more severe disease

• National antiviral stockpile: 55 million doses• Saskatchewan Stockpile:

– 1.7m doses– Enough to treat 170,000 people

Masks

• no evidence to suggest that wearing masks will prevent the spread of infection in the general population.

• Improper use of masks may in fact increase the risk of infection. 

• Stay home when ill but if you must go out when ill, cover your cough and wear a mask if you have one.

• Recommended primarily for use in health care situations. Consider if caring for family member.

Should pregnant women take special precautions to protect themselves?

• It's important that people continue their daily lives during the pandemic.

• PHAC doesn't recommend that pregnant women avoid going to work, or community social events if they are healthy.

• In other crowded situations that cannot be avoided, extra precautions should be taken such as frequent handwashing, to avoid picking up the virus. Pregnant women might consider carrying hand sanitizer for the same purpose.

Guidelines for Schools

SK Ministry of Health• Pandemic H1N1 Flu Prevention and Management • Guidance - August 24, 2009 For Post-Secondary Institutions and Schools

with Student Residences • http://www.health.gov.sk.ca/h1n1-flu-guidance-post-sec-24-aug-2009

Public Health Agency of Canada• Public Health Guidance for Post Secondary and Boarding Schools

regarding the Prevention and Management of Influenza-like-illness (ILI), Including the Pandemic (H1N1) 2009 influenza Virus Aug 19 2009

• http://www.phac-aspc.gc.ca/alert-alerte/h1n1/hp-ps/psili-eng.php

• Fight Flu• http://www.fightflu.ca/index-eng.html

School closures

• Proactive: not recommended. At this point in the pandemic in Canada it is not felt that widespread proactive school closures would be of sufficient benefit to warrant the many costs this measure would entail.  

• Individual reactive post secondary or boarding school closures remains at the discretion of appropriate local authorities in accordance with provincial/territorial legislation.  Such decisions should be based on considerations such as the impact of school absenteeism and/or staff shortages on safe school operations. 

• Consider the many protective factors present in post secondary and boarding school settings. Such settings are excellent places to:

– educate, inform and communicate with students, their families, staff and faculty in an efficient and timely manor,

– support the economic and social elements of the community by continuing to operate,

– provide a structured environment able to support efficient and effective administration of vaccines.

Outbreaks

• Post secondary and boarding schools should develop programs for monitoring of student/staff and faculty illness and develop a strategy to recognize an outbreak – Examples : absenteeism of students/staff is greater than what

would normally be expected on any day or when unusual or more severe illness is observed.

• Prompt action will help to ensure appropriate measures can be implemented to mitigate the impact and spread of the illness to both students and staff.– consult with public health

• Jean Leitner CD control nurse446 6400 ext 6403

Cleaning

• High touch surfaces in post secondary and boarding schools recommended to be cleaned at least twice daily.  

• No special disinfectants or waste handling practices are required for influenza:– regular household or commercially available cleaning products

are sufficient for this purpose – waste handling would be according to usual standards.

• All sinks in washrooms, kitchens and classrooms should be well stocked with hand washing supplies at all times (i.e., soap and paper towels).  

• Consider the use of alcohol-based hand rubs (with 60-90% alcohol) in classrooms without hand washing sinks.

What can you do ?

• Learn what influenza is and how it is spread• Practice infection prevention at all times to

reduce risk of all infections • Prepare your family, your business, your

organization for emergencies• Stay healthy – stop smoking, eat well, exercise

and get enough sleep• Remain calm - remember most people recover

from influenza (even in a pandemic )

Questions ??