flu_and_pandemic by fjhuangjun


									   Influenza Primer:
Seasonal and Pandemic

        October 2, 2009
       Dr. Judy MacDonald
  Deputy Medical Officer of Health

 Information and
 recommendations will
 change as further
 information about the
 epidemiology of pandemic
 H1N1 and its clinical
 course is available.

                     www.albertahealthservices.ca   2
• Terminology
• Influenza Basics, Pandemic Primer
• Update on H1N1 – epidemiology, characteristics
• Pandemic Planning
   – Alberta Health Services – Calgary zone
   – Public Health Measures
• Relevance to Post-secondary Institutions

                      www.albertahealthservices.ca   3
• pandemic - “pan” = all “demos” = the people
   – occurrence of large numbers of cases of a
     [communicable] disease at the same time around the
• epidemic - “epi” = upon “demos” = the people
   – occurrence of cases of a [communicable] disease in
     excess of normal expectations
• endemic - “en” = in “demos” = the people
   – occurrence of cases of [communicable] disease at a
     constant background level
                       www.albertahealthservices.ca       4
• seasonal influenza is caused by viruses that are already
  among people
• avian influenza is a contagious
   disease in birds caused by
  influenza A viruses
                                                Source: WHO avian influenza website
• swine influenza is a disease in pigs
  caused by influenza A viruses that can also infect humans
• pandemic influenza emerges as a result of major genetic
  changes in the influenza A virus
                        www.albertahealthservices.ca                            5
Influenza - the Virus
• 3 types - A, B and C
                host of origin (if not human)
         A/California/7/2009 (H1N1)

             geographic strain        year of        HA NA
      type    origin    number       isolation       subtype

• epidemics - A and B; pandemics - A only

                      www.albertahealthservices.ca             6
Influenza A – the Virus
8 internal genes
                                • spherical RNA virus
                                • influenza A subtypes classified
                                  by surface antigens:
                                      – haemagglutinin (H) - H1,
                                        H2, H3
                                      – neuraminidase (N) – N1,
                                • surface antigens unstable,
                                  change constantly
                   www.albertahealthservices.ca                7
Pandemic History
• earliest report of epidemic – 412 BC (Hippocrates)
• earliest recorded pandemic - 1580
     Asia     Africa     Europe     Americas
   – high death rates (CFR 11% in Rome)
• 17th century – localized epidemics
• 18th century – at least 3 pandemics (1729-30;
  1732-33; 1781-82)
• 19th century – 3 pandemics (1830-31; 1833-34; 1889-
                    www.albertahealthservices.ca    8
Pandemics of the 20th Century
                   SPANISH                ASIAN           HONG KONG
    Strain          A(H1N1)               A(H2N2)           A(H3N2)

     Year            1918-19               1957-58          1968-69

 Likely origin     Not known                China            China

  Estimated      20 - 40 million/         1 million/       1- 4 million/
   deaths        30-50 thousand           12,000 or         12,000 or
Global/Canada                               more              more
Age group most     20-50 years          Very young          Very old,
   affected                             and very old       those with
                                                          other medical
                           www.albertahealthservices.ca                    9
WHO Pandemic Phases

           www.albertahealthservices.ca   10
 As of Sept 20:
# confirmed cases >300,000
# deaths 3917
As of July 15:
10,156 cases
(individual cases
                                              Case count
   not reported
                                              July 15
  after this date)

As of Sept 19:
1,467 hospitalized
cases, 292 ICU cases

As of Sept 19:
78 deaths

                       www.albertahealthservices.ca        12
Influenza tests reported and percentage of tests
   positive, Canada, by report week, 2008-2009
                                                  Jun 7-13
                    Apr 26 – May 2

                   www.albertahealthservices.ca              13
Canadian Influenza Surveillance

 97.7% of typed positive influenza A specimens = Pandemic H1N1
                        www.albertahealthservices.ca             14
H1N1 Laboratory Findings
• All pandemic (H1N1) 2009 viruses tested to date are
  antigenically similar to the A/California/7/2009
  vaccine virus

• Pandemic viruses sequenced to date are all closely
  related to A/California/7/2009 virus with very minor
  genetic variation (no reassortment with other
  influenza viruses)

• Serology studies: older adults less vulnerable

                       www.albertahealthservices.ca      15
FluWatch: www.phac-aspc.gc.ca/fluwatch/09-10/w37_09/index-eng.php
                         www.albertahealthservices.ca               16
 H1N1 Epidemiology
• H1N1 cases:
   – younger than seasonal cases, especially for those with
     severe or fatal illness
   – Usually mild but some develop severe respiratory failure
     (unlike seasonal)
• Vulnerable groups:
   – Pregnant
   – Chronic medical conditions (lung, heart disease; diabetes)
   – Immune compromised
   – Morbid obesity              ?indigenous peoples
                        www.albertahealthservices.ca        17
Canadian Epidemiology

                         Hospitalized cases

FluWatch: www.phac-aspc.gc.ca/fluwatch/09-10/w37_09/index-eng.php

                              www.albertahealthservices.ca          18
Why Worry about this Flu?
• It’s a new strain of influenza
  virus to which most people
  have little or no immunity,
  which may lead to more
  infections than seen with
  seasonal influenza

• Though it’s caused mostly mild
  disease to date, this could

                            www.albertahealthservices.ca   19
The Virus is Spread….

   - Person-to-person via infected droplets expelled by coughing
     and/or sneezing that are inhaled (up to a two-metre distance).
   And Indirectly:
   - From contaminated hands and/or surfaces, with subsequent
     touching of your eyes, nose and/or mouth.

Transmission may be possible over longer distances during aerosol
   generating medical procedures.

                          www.albertahealthservices.ca                20
Signs and Symptoms (Influenza-like Illness)

• Acute onset of new cough or change in existing cough, plus 1 or
  more of the following:
       • Fever (≥ 38 C)
       • Sore throat
       • Joint pain
       • Muscle aches
       • Severe exhaustion
• Some cases - diarrhea, nausea and/or vomiting
• Few cases progress to severe respiratory illness

                          www.albertahealthservices.ca              21
Incubation Period:               Infectious Period (virus shedding):

• Up to 4 days                   • In an untreated previously healthy
                                      – 1 day prior to, and up to 7 days
(seasonal influenza 1-3 days)           after onset of symptoms
                                 • In immune compromised or severely
                                   ill persons:
                                      – prolonged periods

                          www.albertahealthservices.ca                  22
Prevention – Look after Yourself
•   Hand hygiene – diligently and frequently
•   Respiratory etiquette – cover your cough!!
•   Stay away from those who are ill
•   Stay home when you are ill until you are feeling well
    enough to participate fully in daily activities
     – Self Care Strategywww.health.alberta.ca/health-info/influenza-
• Get vaccinated!
• Personal preparedness - www.albertahealthservices.ca/files/ns-

                             www.albertahealthservices.ca               23
What about Masks?
Masks – public use
• no evidence of effectiveness in preventing influenza
  when used in public settings
• may be useful in settings where person is ill with cough
  and fever
• may give false sense of security to wearer - eyes still
  exposed; hands can become contaminated

                       www.albertahealthservices.ca          24
What to do?

 Watch for symptoms of influenza-like illness (ILI):
 • Sudden onset of new cough +/- fever, with one or
   more of: sore throat, muscle aches, joint pain,
   extreme fatigue or weakness
 • Vomiting or diarrhea may also be present, especially
   in young children

                       www.albertahealthservices.ca       25
What to do if you have ILI? (2)

 • If healthy:
    – most illness is mild
    – stay home and recover until symptom-free,
       feeling well and able to participate fully
    – if chest pain, shortness of breath or fever
       lasts more than 3 days, go to doctor
 • If underlying medical condition or pregnant:
    – see your doctor right away for early treatment

                      www.albertahealthservices.ca     26
Mild disease in a previously healthy person does not require

Testing is only recommended for persons with ILI who:
   • Are at higher risk for influenza related complications
     (pregnant, chronic medical conditions, immune
   • Have symptoms severe enough to require admission to

                        www.albertahealthservices.ca          27
• Early treatment with an antiviral (best within 48 hours of
  onset) is only recommended for those at risk of
       • Pregnant women
       • Persons with chronic cardiopulmonary conditions or other co-
         morbid illness
       • Persons with severe disease
       • ≥ 65 years or older (in outbreak settings)

Prophylaxis is not recommended because of possibility of
  antiviral resistance
                           www.albertahealthservices.ca                 28
Pandemic Planning - Health System

overall goals of influenza pandemic preparedness and
  response are:
• first, to reduce morbidity and mortality

• second, to minimize societal disruption among
  Albertans by providing access to appropriate prevention
  measures, care and treatment

Source: Alberta Pandemic Influenza Plan for the Health System, December 2007

                                 www.albertahealthservices.ca                  29
AHS - Pandemic Steering Committee

 Who is involved?
 • AHS Executive
 • Public Health Leads
 • Various Sections and Working Groups:
    – ethics, legal, finance, liaison, operations (acute
      care, community), public health operations,
      logistics, communications, planning (HR, OHS)

                        www.albertahealthservices.ca       30
Capacity Management

• In a pandemic, focus shifts to population survival
• Focus resources on patients with best chance of
  recovery and survival
• Define Essential Health Services
• With diminishing healthcare (non-monetary)
  resources, focus of services should be outcomes

                      www.albertahealthservices.ca     31
Capacity Management

• Addition of Non-Traditional Sites:
   – Influenza Assessment Clinics
   – Alternate Care Centres/Sites
• Re-deployment of workforce
• Mass Vaccination Clinics
   – Challenge: Vaccination of our total population(~1.2

                       www.albertahealthservices.ca        32
• External Web Site (Information, Resources)

• Pandemic Presentations (all levels of the organization,
  municipalities, private and non-profit agencies)

• Tabletop Exercises

• Personal Preparedness Training and Ethics

                        www.albertahealthservices.ca        33
• 55 million doses stockpiled nationally for early
  treatment (90% oseltamivir, 10% zanamivir)

• Developing mechanisms for delivery within 48 hours
  of symptom onset

• May not work against pandemic strain; some
  resistance already reported to oseltamivir

                       www.albertahealthservices.ca    34
Primary public health intervention during pandemic to
  decrease morbidity and mortality
• need to provide safe and effective vaccine program to
  all Canadians as quickly as possible
• need to allocate, distribute and administer vaccine
  as rapidly as possible to appropriate groups of people
• must monitor safety and effectiveness of vaccination

 Reference: CPIP, 2006

                         www.albertahealthservices.ca      35
H1N1 Vaccine
• No cross protection from
  seasonal influenza vaccine
• Vaccines developed for use in
• Enough vaccine for whole
• One dose of vaccine needed
  for most people
• Expected to be available in
  November 2009

                     www.albertahealthservices.ca   36
Outstanding questions
• Will disease severity change?
• Will pandemic H1N1 virus
  replace seasonal influenza
  strains as predominant
  circulating influenza virus?
   – Likely but seasonal
      influenza strains also
      expected to circulate at
      lower levels (~10-20%)
• Will new risk factors be
                     www.albertahealthservices.ca   37
What’s the relevance to you?
 H1N1 outbreak hits US university – Calgary Herald,
   Monday, Sept 7, 2009

 • 2000 students reporting symptoms of ILI in first 20
   days of fall semester

 • Blog set up to provide information to students about
   how to prevent illness and further spread

                       www.albertahealthservices.ca       38
Are you prepared?
• PHAC - 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

                       www.albertahealthservices.ca           39

• Alberta Health & Wellness
• Alberta Health Services www.albertahealthservices.ca
• Public Health Agency of Canada

                     www.albertahealthservices.ca          40

              www.albertahealthservices.ca   41

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