Swine FluSwine FluOlga Emgushov, MD, MPHOlga Emgushov, MD, MPH

Director Epidemiology/Public Health Director Epidemiology/Public Health PreparednessPreparedness

Brevard County Health DepartmentBrevard County Health DepartmentApril 30, 2009April 30, 2009

Current Swine Influenza SituationCurrent Swine Influenza Situation

Updated frequently on CDC website Updated frequently on CDC website http://www.cdc.gov/swineflu/http://www.cdc.gov/swineflu/

109 cases in US with 1 death109 cases in US with 1 death 57 confirmed cases around the globe with 7 57 confirmed cases around the globe with 7

deaths (Mexico) deaths (Mexico) •• Mexico(26), Canada (13), UK (5), Spain (4), Mexico(26), Canada (13), UK (5), Spain (4), •• Mexico(26), Canada (13), UK (5), Spain (4), Mexico(26), Canada (13), UK (5), Spain (4),

Germany/New Zealand (3 each), Isreal (2), Austria (1)Germany/New Zealand (3 each), Isreal (2), Austria (1) WHO phase 5 (evidence of significant humanWHO phase 5 (evidence of significant human--

human transmission) a strong signal that a human transmission) a strong signal that a pandemic is imminent and time to finalize planspandemic is imminent and time to finalize plans

US declared public health emergency which sets US declared public health emergency which sets certain activities in motion such as the Strategic certain activities in motion such as the Strategic National Stockpile (antiviral drugs) National Stockpile (antiviral drugs) –– vaccine vaccine developmentdevelopment

What is Swine Flu?What is Swine Flu?

Respiratory disease of pigs caused Respiratory disease of pigs caused by a type A influenza virus that by a type A influenza virus that causes regular outbreaks in pigscauses regular outbreaks in pigs

People do not normally get swine fluPeople do not normally get swine flu People do not normally get swine fluPeople do not normally get swine flu However this current swine flu is However this current swine flu is

contagious and spreading from contagious and spreading from person to person person to person –– we just are not we just are not sure how easily it is spreading (can sure how easily it is spreading (can NOT get if from eating pork)NOT get if from eating pork)

CDC SwineCDC Swine––origin Influenza Aorigin Influenza A(S(S--OIV) Case DefinitionOIV) Case Definition

(4/29/09 (4/29/09 –– 2am)2am) Confirmed:Confirmed:

•• Person with an acute febrile respiratory Person with an acute febrile respiratory illness with lab confirmed Sillness with lab confirmed S--OIV OIV infection by CDCinfection by CDCinfection by CDCinfection by CDC

Probable:Probable:•• Person with acute febrile respiratory Person with acute febrile respiratory

illness who is positive for influenza A, illness who is positive for influenza A, but negative for current seasonal but negative for current seasonal influenzainfluenza

Suspected SSuspected S--OIVOIV

Person with acute febrile respiratory Person with acute febrile respiratory illness with onsetillness with onset•• Within 7 days of close contact with a Within 7 days of close contact with a

confirmed caseconfirmed caseconfirmed caseconfirmed case•• Within 7 days of travel to affected Within 7 days of travel to affected

communitycommunity•• Resides in affected community (>1 Resides in affected community (>1

confirmed case)confirmed case)

Seasonal InfluenzaSeasonal Influenza

Spreads from person to person Spreads from person to person through respiratory dropletsthrough respiratory droplets•• usually coughing, sneezingusually coughing, sneezing•• within 3 feetwithin 3 feet•• within 3 feetwithin 3 feet

but can contaminate surfaces and but can contaminate surfaces and then spread by touching one’s eyes, then spread by touching one’s eyes, nose or mouthnose or mouth

Season Influenza in the USSeason Influenza in the US

20% of the population become sick20% of the population become sick 200,000 are hospitalized200,000 are hospitalized 36,000 die each year36,000 die each year

This past season there were 8 This past season there were 8 This past season there were 8 This past season there were 8 pediatric deaths (<18yo)pediatric deaths (<18yo)

CommunicabilityCommunicability

How does someone with the flu How does someone with the flu infect someone else?infect someone else?

Infected people can infect others Infected people can infect others beginning 1 day before symptoms beginning 1 day before symptoms appear and up to 7 days after appear and up to 7 days after becoming sickbecoming sick

How do I protect myself and myHow do I protect myself and myfamily?family?

Most important Most important –– wash your hands often! wash your hands often! (studies (studies –– 4x day, hand sanitizers also)4x day, hand sanitizers also)

Avoid close contact with sick peopleAvoid close contact with sick people Stay home when you are sickStay home when you are sick Stay home when you are sickStay home when you are sick Cover mouth and nose when Cover mouth and nose when

coughing/sneezingcoughing/sneezing Avoid touching your eyes, nose, mouthAvoid touching your eyes, nose, mouth Stay in good health (sleep, exercise, diet)Stay in good health (sleep, exercise, diet)

What is BCHD doing?What is BCHD doing?

Active Surveillance Active Surveillance –– Sentinel Physicians Sentinel Physicians testing first 5 ILI/week plus suspected testing first 5 ILI/week plus suspected casescases

All physicians/labs in county directed to All physicians/labs in county directed to test suspected casestest suspected casestest suspected casestest suspected cases

Working with community partners (EOC, Working with community partners (EOC, school, law, fire, etc)school, law, fire, etc)

Following pandemic influenza planFollowing pandemic influenza plan In Rapid Response and Containment In Rapid Response and Containment

PhasePhase

Rapid Response and ContainmentRapid Response and Containment

Find all the cases of the infectious Find all the cases of the infectious disease and isolate them voluntarily disease and isolate them voluntarily at homeat home

Monitor the close contacts Monitor the close contacts –– if they if they Monitor the close contacts Monitor the close contacts –– if they if they get sick they count as cases get sick they count as cases –– their their contacts become new monitored contacts become new monitored contactscontacts

DefinitionsDefinitions

IsolationIsolation•• Separation of ill persons with contagious diseasesSeparation of ill persons with contagious diseases•• For ill peopleFor ill people•• Usually in hospital, but can be at home or in a dedicated Usually in hospital, but can be at home or in a dedicated

isolation facilityisolation facility

QuarantineQuarantine QuarantineQuarantine•• Separation or restriction of movement of select Separation or restriction of movement of select

person(s)person(s)•• For people exposed but not illFor people exposed but not ill•• Home, institutional, or other forms (“work quarantine”)Home, institutional, or other forms (“work quarantine”)•• Voluntary vs. compulsoryVoluntary vs. compulsory

Social Distancing andSocial Distancing andInfection ControlInfection Control

Social distancing (contact interventions)Social distancing (contact interventions)•• School closureSchool closure•• Work closure (telecommuting) Work closure (telecommuting) •• Cancellation of public gatheringsCancellation of public gatherings

Infection control (transmission Infection control (transmission interventions)interventions)•• Face masksFace masks•• Cough etiquetteCough etiquette•• Hand hygieneHand hygiene

3 probable cases in FL3 probable cases in FL

Orange, Broward, LeeOrange, Broward, Lee Awaiting CDC testingAwaiting CDC testing Have been tested by FL DOH state Have been tested by FL DOH state

lab and are flu A positive and human lab and are flu A positive and human lab and are flu A positive and human lab and are flu A positive and human H1 and H3 (current seasonal flu) H1 and H3 (current seasonal flu) negativenegative

Question? Is Orange County part of Question? Is Orange County part of our community? our community? –– I am still waiting I am still waiting state DOH guidancestate DOH guidance

Containment UnlikelyContainment Unlikely

Failed containment may still delay international spread by 1 monthSevere travel restrictions may delay U.S. cases by 1-4 weeks

Without intervention, expect international spread in 1 month and U.S. cases in 1 to 2 months.

CommunityCommunity--Based InterventionsBased Interventions

1. Delay disease transmission and 1. Delay disease transmission and outbreak peakoutbreak peak

2. Decompress peak burden on 2. Decompress peak burden on healthcare infrastructurehealthcare infrastructurehealthcare infrastructurehealthcare infrastructure

3. Diminish overall cases and health 3. Diminish overall cases and health impactsimpacts

EPI curveEPI curve

#1

Pandemic outbreak:

DailyCases

#2

#3

Days since First Case

Pandemic outbreak:No intervention

Pandemic outbreak:With intervention

1918 Weekly Excess Death Rate by City

0.008

0.01

0.012

0.014

0.016

0.018

Ex

ce

ss

De

ath

Ra

te Baltimore

Boston

Milwaukee

Minneapolis

Philadelphia

0

0.002

0.004

0.006

0.008

9/14

/191

8

9/21

/191

8

9/28

/191

8

10/5

/191

8

10/1

2/19

18

10/1

9/19

18

10/2

6/19

18

11/2

/191

8

11/9

/191

8

11/1

6/19

18

11/2

3/19

18

11/3

0/19

18

12/7

/191

8

12/1

4/19

18

12/2

1/19

18

12/2

8/19

18

Date

Ex

ce

ss

De

ath

Ra

te

Philadelphia

Pittsburgh

St. Louis

Susceptible to Targeted AttackSusceptible to Targeted Attack1918 Age1918 Age--Specific Attack RatesSpecific Attack Rates

Who Infects Who?Who Infects Who?

To ChildrenTo Children To TeenagersTo Teenagers To AdultsTo Adults To SeniorsTo Seniors Total FromTotal From

From ChildrenFrom Children 21.421.4 3.03.0 17.417.4 1.61.6 43.443.4

From TeenagersFrom Teenagers 2.42.4 10.410.4 8.58.5 0.70.7 21.921.9

From AdultsFrom Adults 4.64.6 3.13.1 22.422.4 1.81.8 31.831.8

From SeniorsFrom Seniors 0.20.2 0.10.1 0.80.8 1.71.7 2.82.8

Total ToTotal To 28.628.6 16.616.6 49.049.0 5.75.7

Children/Teenagers 29%Adults 59%Seniors 12%

Layered InterventionsLayered Interventions

↓ cases↑ HH & community transmission

Close schools2.1

1.9

1.9

1.5

Keep kids home↓ HH & community transmission↑ relative importance of HH

HH quarantine↓ cases↑ relative importance of

workplace & community

Social distancing ↓ cases

1.21.5

↑ relative importance of HH & workplace transmission

1.20.9

PopulationPopulation--based Containmentbased Containment

Symptomatic /

Influenza

Prophylaxis

TreatmentIsolation

Exposure

Latent / Infectious

Symptomatic / Infectious

Susceptible

Asymptomatic / Infectious

Quarantine / IsolationSocial DistancingLiberal LeaveSchool ClosureInfection Control

Infection ControlSocial DistancingSchool ClosureTargeted Social Distancing

Shunting

Shape of an EpidemicShape of an Epidemic

Susceptible to Targeted AttackSusceptible to Targeted Attack

Susceptible to Targeted AttackSusceptible to Targeted Attack

Value of Combining StrategiesValue of Combining Strategies ––Ferguson ModelFerguson Model

20

30

40

0

10

Clinical attack rate

Base case (Ro=2.0)

90% case treatment + school closure

90% case treatment + school closure + 90% household prophylaxis

90% case treatment + school closure + 90% household prophylaxis + 70% household quarantine

Source: Ferguson N, Nature (online) April 26, 2006

Combining strategiesCombining strategies –– Glass model:Glass model:Targeted Social DistancingTargeted Social Distancing

15

20

25

30

% o

f p

op

ula

tio

n

0

5

10

15

Clinical attack rate

Base case (Ro ~ 1.6)School closure aloneSchool closure + targeted social distancing (10% compliance)School closure + targeted social distancing (30% compliance)School closure + targeted social distancing (50% compliance)School closure + targeted social distancing (90% compliance)

% o

f p

op

ula

tio

n

Evidence to Support School ClosureEvidence to Support School Closure

Children are thought to be the main Children are thought to be the main introducers of influenza into households.introducers of influenza into households.

Children appear to be more susceptible to Children appear to be more susceptible to influenza and more infectious than adults in influenza and more infectious than adults in wellwell--designed prospective studies of risk designed prospective studies of risk factors of influenza transmission in households.factors of influenza transmission in households.factors of influenza transmission in households.factors of influenza transmission in households.

Nationwide school closure in Israel during an Nationwide school closure in Israel during an influenza epidemic resulted in significant influenza epidemic resulted in significant decreases in the diagnoses of respiratory decreases in the diagnoses of respiratory infections (42%), visits to physicians (28%) infections (42%), visits to physicians (28%) and emergency departments (28%), and and emergency departments (28%), and medication purchases (35%). medication purchases (35%).

What do the Modeling ResultsWhat do the Modeling ResultsMean?Mean?

Not proof of efficacy or effectiveness, Not proof of efficacy or effectiveness, BUT offer BUT offer reason for optimismreason for optimismregarding nonregarding non--pharmaceutical pharmaceutical interventionsinterventions

Suggest that maximal effectiveness will Suggest that maximal effectiveness will be achieved by appropriate layering and be achieved by appropriate layering and

Suggest that maximal effectiveness will Suggest that maximal effectiveness will be achieved by appropriate layering and be achieved by appropriate layering and timingtiming

Need to be evaluated based upon Need to be evaluated based upon assumptions and validated against assumptions and validated against experienceexperience