Swine Flu

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Swine Flu

• Olga Emgushov, MD, MPH
• Director Epidemiology/Public Health Preparedness
• Brevard County Health Department
• April 30, 2009

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Current Swine Influenza Situation

• Updated frequently on CDC website
  http//www.cdc.gov/swineflu/
• 109 cases in US with 1 death
• 57 confirmed cases around the globe with 7 deaths
  (Mexico)
• Mexico(26), Canada (13), UK (5), Spain (4),
  Germany/New Zealand (3 each), Isreal (2), Austria
  (1)
• WHO phase 5 (evidence of significant human-human
  transmission) a strong signal that a pandemic is
  imminent and time to finalize plans
• US declared public health emergency which sets
  certain activities in motion such as the
  Strategic National Stockpile (antiviral drugs)
  vaccine development

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What is Swine Flu?

• Respiratory disease of pigs caused by a type A
  influenza virus that causes regular outbreaks in
  pigs
• People do not normally get swine flu
• However this current swine flu is contagious and
  spreading from person to person we just are not
  sure how easily it is spreading (can NOT get if
  from eating pork)

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CDC Swineorigin Influenza A (S-OIV) Case
Definition (4/29/09 2am)

• Confirmed
• Person with an acute febrile respiratory illness
  with lab confirmed S-OIV infection by CDC
• Probable
• Person with acute febrile respiratory illness who
  is positive for influenza A, but negative for
  current seasonal influenza

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Suspected S-OIV

• Person with acute febrile respiratory illness
  with onset
• Within 7 days of close contact with a confirmed
  case
• Within 7 days of travel to affected community
• Resides in affected community (1 confirmed case)

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Seasonal Influenza

• Spreads from person to person through respiratory
  droplets
• usually coughing, sneezing
• within 3 feet
• but can contaminate surfaces and then spread by
  touching ones eyes, nose or mouth

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Season Influenza in the US

• 20 of the population become sick
• 200,000 are hospitalized
• 36,000 die each year
• This past season there were 8 pediatric deaths
  (

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Communicability

• How does someone with the flu infect someone
  else?
• Infected people can infect others beginning 1 day
  before symptoms appear and up to 7 days after
  becoming sick

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How do I protect myself and my family?

• Most important wash your hands often! (studies
  4x day, hand sanitizers also)
• Avoid close contact with sick people
• Stay home when you are sick
• Cover mouth and nose when coughing/sneezing
• Avoid touching your eyes, nose, mouth
• Stay in good health (sleep, exercise, diet)

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What is BCHD doing?

• Active Surveillance Sentinel Physicians testing
  first 5 ILI/week plus suspected cases
• All physicians/labs in county directed to test
  suspected cases
• Working with community partners (EOC, school,
  law, fire, etc)
• Following pandemic influenza plan
• In Rapid Response and Containment Phase

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Rapid Response and Containment

• Find all the cases of the infectious disease and
  isolate them voluntarily at home
• Monitor the close contacts if they get sick
  they count as cases their contacts become new
  monitored contacts

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Definitions

• Isolation
• Separation of ill persons with contagious
  diseases
• For ill people
• Usually in hospital, but can be at home or in a
  dedicated isolation facility
• Quarantine
• Separation or restriction of movement of select
  person(s)
• For people exposed but not ill
• Home, institutional, or other forms (work
  quarantine)
• Voluntary vs. compulsory

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Social Distancing and Infection Control

• Social distancing (contact interventions)
• School closure
• Work closure (telecommuting)
• Cancellation of public gatherings
• Infection control (transmission interventions)
• Face masks
• Cough etiquette
• Hand hygiene

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3 probable cases in FL

• Orange, Broward, Lee
• Awaiting CDC testing
• Have been tested by FL DOH state lab and are flu
  A positive and human H1 and H3 (current seasonal
  flu) negative
• Question? Is Orange County part of our community?
  I am still waiting state DOH guidance

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Containment Unlikely
Without intervention, expect international
spread in 1 month and U.S. cases in 1 to 2 months.
Failed containment may still delay international
spread by 1 month Severe travel restrictions may
delay U.S. cases by 1-4 weeks
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Community-Based Interventions

• 1. Delay disease transmission and outbreak peak
• 2. Decompress peak burden on healthcare
  infrastructure
• 3. Diminish overall cases and health impacts

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EPI curve
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Susceptible to Targeted Attack 1918 Age-Specific
Attack Rates
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Who Infects Who?
Children/Teenagers 29 Adults
59 Seniors 12
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Layered Interventions
1.9
2.1
? cases ? HH community transmission
Close schools
1.5
1.9
? HH community transmission ? relative
importance of HH workplace transmission
Keep kids home
1.2
1.5
? cases ? relative importance of workplace
community
HH quarantine
1.2
0.9
Social distancing
? cases
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Population-based Containment
Treatment Isolation
Influenza
Prophylaxis
Symptomatic / Infectious
Shunting
Exposure
Susceptible
Latent / Infectious
Quarantine / Isolation Social Distancing Liberal
Leave School Closure Infection Control
Asymptomatic / Infectious
Infection Control Social Distancing School
Closure Targeted Social Distancing
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Shape of an Epidemic
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Susceptible to Targeted Attack
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Susceptible to Targeted Attack
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Value of Combining Strategies Ferguson Model
Source Ferguson N, Nature (online) April 26, 2006
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Combining strategies Glass modelTargeted
Social Distancing
of population
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Evidence to Support School Closure

• Children are thought to be the main introducers
  of influenza into households.
• Children appear to be more susceptible to
  influenza and more infectious than adults in
  well-designed prospective studies of risk factors
  of influenza transmission in households.
• Nationwide school closure in Israel during an
  influenza epidemic resulted in significant
  decreases in the diagnoses of respiratory
  infections (42), visits to physicians (28) and
  emergency departments (28), and medication
  purchases (35).

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What do the Modeling Results Mean?

• Not proof of efficacy or effectiveness, BUT offer
  reason for optimism regarding non-pharmaceutical
  interventions
• Suggest that maximal effectiveness will be
  achieved by appropriate layering and timing
• Need to be evaluated based upon assumptions and
  validated against experience

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WHO Pandemic Influenza Phase
3
4
5
6
Rare clusters Small number of cases per
cluster Very limited human-to-human transmission
Localized
Frequent clusters More cases per
cluster Common human-to-human transmission Local
ized
Continuous transmission Regular human-to-human tr
ansmission Involves general population of large
regions (worldwide)
Human infections with new subtype No
clusters No human-to-human transmission
Virus with low pandemic potential
Virus with high pandemic potential
No sustained human transmission
Sustained human transmission
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WHO Pandemic Influenza Phase
Proposed U.S. Public Health Response in
Relationship to WHO Phases
3
4
5
6
Early
Late
Imported cases possible
Social distancing Individual
Community
Household
Quarantine No
Yes
Isolation Individual
Community
Virus with low pandemic potential
Virus with high pandemic potential
No sustained human transmission
Sustained human transmission
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Nonpharmaceutical Interventions

• Depend on virus transmission characteristics and
  illness severity
• Measures at borders (international or within
  countries)- limited early focus, phase 5-6a
• Travel health alert notices (T-HAN)
• Entry screening of international travelers
• Exit screening from affected countries is
  recommended, especially if most countries not yet
  affected

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Targeted Layered Containment Summary
Nonpharmaceutical Interventions

• Ill persons should be isolated (home vs
  hospital)
• Voluntary home quarantine for household contacts
• Social distancing measures
• School closures may have profound impact
• Workplace COOP (liberal leave NOT closure)
• Cancellation of public events?
• Individual infection control measures
• Hand washing and cough etiquette for all
• Mask use for ill persons, PPE stratified by risk
• Disinfection of environmental surfaces as needed