alameda county influenza update

Alameda County Alameda County Influenza UpdateInfluenza Update

Rosilyn Ryals, M.D.Rosilyn Ryals, M.D.Division of Communicable Disease Division of Communicable Disease

Control & PreventionControl & PreventionAlameda County Public Health DepartmentAlameda County Public Health Department

November 2005November 2005

OutlineOutline

Influenza Influenza The Pandemic ThreatThe Pandemic Threat

What is Influenza?What is Influenza? Contagious, acute, febrile, respiratory Contagious, acute, febrile, respiratory

illness caused by virusesillness caused by viruses Epidemics of influenza occur during winter Epidemics of influenza occur during winter

months in temperate regions, like the U.S.months in temperate regions, like the U.S. Every year in the United states:Every year in the United states:

» 5 to 20% of the population get flu5 to 20% of the population get flu» >200,000 people are hospitalized from flu >200,000 people are hospitalized from flu

complicationscomplications» Approximately 36,000 people die from flu Approximately 36,000 people die from flu

(primarily high risk persons)(primarily high risk persons)

High Risk PopulationHigh Risk Population Adults Adults >>65 years65 years Children 6-23 monthsChildren 6-23 months Persons aged 2-64 yrs. with chronic lung, heart or Persons aged 2-64 yrs. with chronic lung, heart or

metabolic disorders:metabolic disorders:-- heart disease (ever diagnosed) heart disease (ever diagnosed) -- asthma (taking medication)asthma (taking medication)-- diabetes (ever diagnosed)diabetes (ever diagnosed)

Persons with hemoglobinopathies or Persons with hemoglobinopathies or immunosuppressionimmunosuppression

Children and adolescents on long-term aspirin therapyChildren and adolescents on long-term aspirin therapy Women pregnant during influenza seasonWomen pregnant during influenza season

High Risk Population High Risk Population (continued)(continued) Adults and children who have any condition that can Adults and children who have any condition that can

compromise respiratory function.compromise respiratory function. Residents of nursing homes and other chronic-care Residents of nursing homes and other chronic-care

facilitiesfacilitiesPlus those in close contact with high risk personsPlus those in close contact with high risk persons:: Household members and out-of-home care givers of Household members and out-of-home care givers of

infants under the age of 6 mos. infants under the age of 6 mos. Healthcare workers who provide direct, hands-on Healthcare workers who provide direct, hands-on

care to patients care to patients -- ambulatory health care servicesambulatory health care services-- hospitalshospitals-- nursing and residential care facilitiesnursing and residential care facilities

High Risk Group Impact on High Risk Group Impact on Alameda CountyAlameda County

Alameda County has a population of about Alameda County has a population of about 1.5 million people1.5 million people

The high risk groups identified comprise The high risk groups identified comprise approximately 1/3 of the county populationapproximately 1/3 of the county population

HH w/ infants 12%

>=65 32%

nursing homes 1%

HCW6%

6-23 mos.7%pregnant women

6%

2-64 - chronic disease

36%

High Risk GroupsHigh Risk Groups

Symptoms of InfluenzaSymptoms of Influenza FeverFever HeadacheHeadache MalaiseMalaise CoughCough Sore ThroatSore Throat Runny or stuffy noseRunny or stuffy nose MyalgiaMyalgia GI symptoms (nausea, vomiting, and GI symptoms (nausea, vomiting, and

diarrhea) – primarily in childrendiarrhea) – primarily in children

Influenza-CourseInfluenza-Course Incubation: 1-4 days, averagely 2 daysIncubation: 1-4 days, averagely 2 days Adults can be infectious from the day Adults can be infectious from the day

before symptoms until about 5 days after before symptoms until about 5 days after onsetonset

Children may be infectious Children may be infectious >> 10 days 10 days Severely immunocompromised persons Severely immunocompromised persons

may shed virus for weeks or monthsmay shed virus for weeks or months Uncomplicated influenza illness typically Uncomplicated influenza illness typically

resolves in 3-7 daysresolves in 3-7 days

Influenza- ComplicationsInfluenza- Complications Pneumonia – usually secondary bacterialPneumonia – usually secondary bacterial DehydrationDehydration Exacerbation of chronic conditions Exacerbation of chronic conditions Sinus and ear infections (children)Sinus and ear infections (children) Febrile seizures in childrenFebrile seizures in children

Biology of InfluenzaBiology of Influenza Influenza viruses belong to the family Influenza viruses belong to the family

OrthomyxoviridaeOrthomyxoviridae There are 3 distinct types of influenza: A, B and CThere are 3 distinct types of influenza: A, B and C Influenza A and B are the two types that cause epidemic Influenza A and B are the two types that cause epidemic

human diseasehuman disease Influenza A is further categorized into subtypes on the Influenza A is further categorized into subtypes on the

basis of two surface antigens: hemagglutinin (basis of two surface antigens: hemagglutinin (HH) and ) and neuraminidase (neuraminidase (NN))

Type A Influenza has 16 different Type A Influenza has 16 different HHs and 9 different s and 9 different NNss Human disease with Influenza A has historically been Human disease with Influenza A has historically been

caused by three subtypes of caused by three subtypes of H H (H1, H2, and H3) and (H1, H2, and H3) and two subtypes of two subtypes of NN (N1 and N2) (N1 and N2)

Biology of Influenza Biology of Influenza (continued)(continued)

All known subtypes of influenza A can be found in All known subtypes of influenza A can be found in birdsbirds

Influenza B viruses are not categorized into Influenza B viruses are not categorized into subtypes.subtypes.

Standard nomenclature for influenza viruses Standard nomenclature for influenza viruses includes: (1) Influenza type, (2) Place of initial includes: (1) Influenza type, (2) Place of initial isolation, (3) Strain designation, and (4) Year of isolation, (3) Strain designation, and (4) Year of isolation, and (5) isolation, and (5) H and N sH and N subtypes for Influenza ubtypes for Influenza A. For example, influenza A isolated in a California A. For example, influenza A isolated in a California patient in 2004 would be written as: patient in 2004 would be written as:

A/California/7/2004 (H3N2)A/California/7/2004 (H3N2)


Influenza A viruses are the most Influenza A viruses are the most worrisome of all the well-established worrisome of all the well-established infectious diseases:infectious diseases:

» Mutate rapidly Mutate rapidly » In addition to humans, they infect pigs, horses, sea In addition to humans, they infect pigs, horses, sea

mammals, and birdsmammals, and birds» They have a large number of subtypes maintained in They have a large number of subtypes maintained in

aquatic birds, providing a perpetual source of aquatic birds, providing a perpetual source of viruses and a huge pool of genetic diversityviruses and a huge pool of genetic diversity


Influenza A viruses are described as Influenza A viruses are described as “sloppy, capricious, and promiscuous” “sloppy, capricious, and promiscuous” because:because:– They lack a proof-reading mechanism to They lack a proof-reading mechanism to detect and detect and

correctcorrect small errors that occur when the viruses copy small errors that occur when the viruses copy themselves.themselves.

– This allows for constant stepwise changes in their This allows for constant stepwise changes in their genetic makeup termed genetic makeup termed antigenic driftantigenic drift

– Though small, these slight variations keep populations Though small, these slight variations keep populations susceptible to infection (susceptible to infection (This explains need for a new This explains need for a new vaccine for each winter season)vaccine for each winter season)


– The genetic content of influenza viruses is segmented The genetic content of influenza viruses is segmented into 8 genesinto 8 genes

– This facilitates the swapping of gene segments during This facilitates the swapping of gene segments during co-infection with hman and avian influenza viruses, co-infection with hman and avian influenza viruses, thereby creating a new virus subtype that will be thereby creating a new virus subtype that will be entirely or largely unfamiliar to the human immune entirely or largely unfamiliar to the human immune system. system.

– If this “If this “novel strainnovel strain” contains a mix of genes causing: ” contains a mix of genes causing: severe diseasesevere disease and allowing and allowing easy human-to-human easy human-to-human transmissiontransmission, a , a pandemic is ignitedpandemic is ignited. This is termed: . This is termed: antigenic shiftantigenic shift..


Usually a single strain of influenza virus Usually a single strain of influenza virus prevails during an epidemicprevails during an epidemic

Occasionally, two different strains within a Occasionally, two different strains within a single subtype (e.g. A/Victoria/3/75 single subtype (e.g. A/Victoria/3/75 (H3N2)or A/Texas/1/77 (H3N2) or two (H3N2)or A/Texas/1/77 (H3N2) or two different influenza A subtypes (H1N1 and different influenza A subtypes (H1N1 and H3N2) may circulate simultaneously.H3N2) may circulate simultaneously.

InfluenzaTransmissionInfluenzaTransmission

Primarily transmitted person-to-person by Primarily transmitted person-to-person by large virus-laden droplets (as generated by large virus-laden droplets (as generated by cough or sneezing within 3 feet of cough or sneezing within 3 feet of susceptible person)susceptible person)

Direct or indirect contact with virus-laden Direct or indirect contact with virus-laden respiratory secretions followed by touching respiratory secretions followed by touching the eyes, nose or mouth of a susceptible the eyes, nose or mouth of a susceptible personperson

Laboratory DiagnosisLaboratory Diagnosis

It is difficult to diagnose based on clinical It is difficult to diagnose based on clinical symptoms alone. Similar symptoms can be symptoms alone. Similar symptoms can be caused by other illnesses, e.g.caused by other illnesses, e.g.

Mycoplasma peumoniaeMycoplasma peumoniae AdenovirusAdenovirus Respiratory Syncytial VirusRespiratory Syncytial Virus RhinovirusRhinovirus Parainfluenza VirusesParainfluenza Viruses Legionella Legionella

Laboratory DiagnosisLaboratory Diagnosis

TESTTEST Time for ResultsTime for Results Viral culture*Viral culture* 3-10 days 3-10 days Serology >2 weeksSerology >2 weeks Rapid antigen testing: <30 minutesRapid antigen testing: <30 minutes PCR 1-2 daysPCR 1-2 days Immunofluorescence assays 2-4 hoursImmunofluorescence assays 2-4 hours*Only culture isolates can provide specific information: *Only culture isolates can provide specific information:

circulating strains and subtypescirculating strains and subtypes

Prevention of InfluenzaPrevention of InfluenzaInter-pandemic PeriodInter-pandemic Period

VACCINATIONVACCINATION

Inactivated Influenza VaccineInactivated Influenza Vaccine

Influenza vaccine can be given to people 6 Influenza vaccine can be given to people 6 months of age and older. It is months of age and older. It is recommended for people who are at risk of recommended for people who are at risk of serious influenza or its complications, and serious influenza or its complications, and for people who can spread influenza to for people who can spread influenza to those at high risk (including all household those at high risk (including all household members)members)

Live Attenuated Influenza Live Attenuated Influenza VaccineVaccine

Live, attenuated influenza vaccine Live, attenuated influenza vaccine (L.A.I.V.) was licensed in 2003. L.A.I.V. (L.A.I.V.) was licensed in 2003. L.A.I.V. contains live but attenuated (weakened) contains live but attenuated (weakened) influenza virus. It is sprayed into the influenza virus. It is sprayed into the nostrils rather than injected into the muscle. nostrils rather than injected into the muscle. It is recommended for healthy children and It is recommended for healthy children and adults from 5 through 49 years of age, who adults from 5 through 49 years of age, who are not pregnant.are not pregnant.

Recipients may shed virus.Recipients may shed virus.

Influenza VaccinationInfluenza Vaccination Influenza viruses are constantly changing. Influenza viruses are constantly changing.

Therefore, influenza vaccines are updated every Therefore, influenza vaccines are updated every year, and annual vaccination is recommended.year, and annual vaccination is recommended.

For most people influenza vaccine prevents For most people influenza vaccine prevents serious illness caused by the influenza virus. It serious illness caused by the influenza virus. It will not prevent “influenza-like” illnesses caused will not prevent “influenza-like” illnesses caused by other viruses.by other viruses.

It takes about 2 weeks for protection to develop It takes about 2 weeks for protection to develop after vaccination, and protection can last up to a after vaccination, and protection can last up to a year.year.

2005-2006 Influenza Vaccine

• Inactivated Influenza Vaccine

A/New Caledonia/20/99 (H1N1)

A/New York/55/2004 (H3N2)

B/Jiangsu/10/2003

• Live attenuated Influenza Vaccine (LAIV)

A/New Caledonia/20/99 (H1N1)

A/California/7/2004 (H3N2)

B/Jiangstu/10/2003

Pneumococcal VaccinationPneumococcal Vaccination

There are two licensed vaccines: There are two licensed vaccines: (1) Pneumococcal Conjugate Vaccine, and (1) Pneumococcal Conjugate Vaccine, and

(2) Pneumococcal Polysaccharide Vaccine.(2) Pneumococcal Polysaccharide Vaccine. Recommendations for Pneumococcal Recommendations for Pneumococcal

Vaccine include Vaccine include population at high risk population at high risk for influenza and its complicationsfor influenza and its complications..

Prevention of InfluenzaPrevention of Influenza

AntiviralsAntivirals

Antiviral therapy and prophylaxis

Adamantine Derivatives:

(1) Amantadine

(2) Rimantadine

Neuraminidase Inhibitors:

(1) Zanamivir

(2) Oseltamivir (Tamiflu)

Antivirals for TreatmentAntivirals for Treatment

Any person with life-threatening influenza-Any person with life-threatening influenza-related illnessrelated illness

Any person at high-risk for serious Any person at high-risk for serious complications of influenza and who is complications of influenza and who is within the first 2 days of illness onsetwithin the first 2 days of illness onset

Antivirals for ProphylaxisAntivirals for Prophylaxis All persons who live or work in institutions All persons who live or work in institutions

caring for people at high risk of caring for people at high risk of complications from influenza should be complications from influenza should be given antiviral medication in the event of an given antiviral medication in the event of an institutional outbreakinstitutional outbreak

Persons at high risk of serious influenza Persons at high risk of serious influenza complications should be given antivirals if complications should be given antivirals if they are likely to be exposed to others they are likely to be exposed to others infected with influenza.infected with influenza.

Impacts of Antiviral Drug TherapyImpacts of Antiviral Drug Therapy AdamantanesAdamantanes

– Reduce duration of illness (1 day)Reduce duration of illness (1 day)– No studies on severity or complicationsNo studies on severity or complications

Oseltamivir (neuraminidase inhibitors)Oseltamivir (neuraminidase inhibitors)– Reduce duration of illnessReduce duration of illness– Pooled analysis of randomized controlled trials*Pooled analysis of randomized controlled trials*

» Decreased hospitalization by 59% (p = .02)Decreased hospitalization by 59% (p = .02)» Decreased lower resp tract illness by 55% (p <.001)Decreased lower resp tract illness by 55% (p <.001)» Decreased antibiotic use by 27% (P <.001)Decreased antibiotic use by 27% (P <.001)

*Kaiser, Arch Intern Med 2003

Prevention of InfluenzaPrevention of Influenza

Infection ControlInfection Control

Infection ControlInfection Control Encourage annual Influenza vaccine for Health Care workersEncourage annual Influenza vaccine for Health Care workers Use of Standard PrecautionsUse of Standard Precautions::

(1) Handwashing(1) Handwashing(2) Gloves(2) Gloves

(3) Mask, Eye Protection, Face Shield: when patient care (3) Mask, Eye Protection, Face Shield: when patient care activities are likely to generate splashes or spraysactivities are likely to generate splashes or sprays

(4) Gown: protect skin and prevent soiling of clothing in patient (4) Gown: protect skin and prevent soiling of clothing in patient care activities that are likely to generate splashes or sprayscare activities that are likely to generate splashes or sprays

(5) Patient-Care Equipment(5) Patient-Care Equipment(6) Environmental Control(6) Environmental Control(7) Linen(7) Linen(8) Occupational Health and Bloodborne Pathogens(8) Occupational Health and Bloodborne Pathogens(9) Patient Placement: private room or cohorting(9) Patient Placement: private room or cohorting


Droplet PrecautionsDroplet Precautions::(1) Patient Placement: Private room; cohort; or maintain at (1) Patient Placement: Private room; cohort; or maintain at

least 3 least 3 feet spatial separationfeet spatial separation

(2) Mask: as per Standard precautions and when working (2) Mask: as per Standard precautions and when working within within

3 feet of an infected patient3 feet of an infected patient (3) Patient transport: limit to essential purposes only; (3) Patient transport: limit to essential purposes only;

minimize minimize dispersal of droplets by masking patient, if possible.dispersal of droplets by masking patient, if possible.


Contact PrecautionsContact Precautions::(1) Patient Placement(1) Patient Placement(2) Gloves and handwashing(2) Gloves and handwashing(3) Gown(3) Gown(4) Patient transport(4) Patient transport(5) Patient-Care Equipment(5) Patient-Care Equipment


Airborne PrecautionsAirborne Precautions (smaller particles than (smaller particles than respiratory droplets); may result from respiratory droplets); may result from procedures like endotracheal intubation, procedures like endotracheal intubation, suctioning, nebulizer treatment, or suctioning, nebulizer treatment, or bronchoscopy. These procedures can result bronchoscopy. These procedures can result in dissemination of airborne droplets over in dissemination of airborne droplets over long distances; requires use of special air-long distances; requires use of special air-handling and ventillation.handling and ventillation.


Airborne Precautions (continued):Airborne Precautions (continued):(1) Patient placement: negative air pressure with 6-12 air (1) Patient placement: negative air pressure with 6-12 air

exchanges per hour, and appropriate discharge of air exchanges per hour, and appropriate discharge of air outdoors; keep door closed; can also cohort if private room outdoors; keep door closed; can also cohort if private room not available.not available.

(2) Respiratory protection: wear an N95 respirator when entering (2) Respiratory protection: wear an N95 respirator when entering roomroom

(3) Limit movement and transport of patient to essential purposes(3) Limit movement and transport of patient to essential purposes If transport or movement is necessary, use mask for patient, if If transport or movement is necessary, use mask for patient, if

possible.possible.


In Doctor’s Offices and Clinics, in additionIn Doctor’s Offices and Clinics, in addition to standard precautions and annual influenzato standard precautions and annual influenza immunization of health care workers:immunization of health care workers:(1)(1) Encourage patients with respiratory and other symptoms consistent Encourage patients with respiratory and other symptoms consistent

with influenza to call in advance of coming in.with influenza to call in advance of coming in.(2)(2) Encourage the use of masks by symptomatic patients or the use of Encourage the use of masks by symptomatic patients or the use of

tissues to cover coughs/sneezestissues to cover coughs/sneezes

Goals of Influenza Surveillance Goals of Influenza Surveillance in the U.S.in the U.S.

» Find out when and where influenza activity is Find out when and where influenza activity is occurringoccurring

» Determine what type of influenza viruses are Determine what type of influenza viruses are circulatingcirculating

» Detect changes in the influenza virusesDetect changes in the influenza viruses» Track influenza-related illnessTrack influenza-related illness» Measure the impact influenza is having on deaths in Measure the impact influenza is having on deaths in

the U.S.the U.S.

U.S. Influenza Surveillance U.S. Influenza Surveillance SystemSystem

(1)(1) 75 WHO and 50 NREVSS Collaborating Labs 75 WHO and 50 NREVSS Collaborating Labs throughout U.S. report: # specimens tested, # positive throughout U.S. report: # specimens tested, # positive for influenza A or Bfor influenza A or B

(2)(2) U.S. Influenza Sentinel Providers Network: 1000 U.S. Influenza Sentinel Providers Network: 1000 providers around the country report number of providers around the country report number of persons seen, and number with influenza-like illness persons seen, and number with influenza-like illness by age groupby age group

(3)(3) 122 Cities Mortality Reporting systems report # of 122 Cities Mortality Reporting systems report # of pneumonia or influenza deathspneumonia or influenza deaths

(4)(4) State and Territorial Epidemiologists report the level State and Territorial Epidemiologists report the level of influenza activity in the stateof influenza activity in the state

(5)(5) Influenza-associated pediatric mortality report lab-Influenza-associated pediatric mortality report lab-confirmed influenza deaths in children <18 years oldconfirmed influenza deaths in children <18 years old

U.S. Influenza Surveillance U.S. Influenza Surveillance SystemSystem(continued)(continued)

(6) Emerging Infections Program conducts surveillance for (6) Emerging Infections Program conducts surveillance for lab-confirmed influenza-related hospitalizations in persons lab-confirmed influenza-related hospitalizations in persons less than 18 years of age in 57 counties throughout U.S. less than 18 years of age in 57 counties throughout U.S. (covering 10 states)(covering 10 states)

(7) New Vaccine Surveillance Network provides population-(7) New Vaccine Surveillance Network provides population-based estimates of lab-confirmed influenza hospitalization based estimates of lab-confirmed influenza hospitalization rates for children <5 years who live in 3 U.S. rates for children <5 years who live in 3 U.S. counties(Ohio, Tennessee, and New York)counties(Ohio, Tennessee, and New York)

Pandemic Influenza: A Pandemic Influenza: A Harbinger of Things to ComeHarbinger of Things to Come

Pandemic InfluenzaPandemic Influenza

Worldwide outbreak of a novel strainWorldwide outbreak of a novel strain Associated with high morbidity, excess Associated with high morbidity, excess

mortality, and social and economic mortality, and social and economic disruptiondisruption

First recorded pandemic that fits influenza First recorded pandemic that fits influenza profile occurred in 1580profile occurred in 1580

Pandemic Influenza in the 20Pandemic Influenza in the 20thth CenturyCentury

1918-19 Spanish Flu (H1N1)1918-19 Spanish Flu (H1N1)» 20-50 million deaths worldwide20-50 million deaths worldwide» >500,000 U.S. deaths>500,000 U.S. deaths

1957-58 Asian Flu (H2N2)1957-58 Asian Flu (H2N2)» 70,000 U.S. deaths70,000 U.S. deaths

1968-69 Hong Kong Flu (H3N2)1968-69 Hong Kong Flu (H3N2)» 50,000 U.S. deaths50,000 U.S. deaths

Avian H5N1 in AsiaAvian H5N1 in Asia Continuing presence in Asia since 1996Continuing presence in Asia since 1996

– Documented direct avian to human transmission, Hong Kong,1997Documented direct avian to human transmission, Hong Kong,1997 Enzootic and epizootic of unprecedented size and Enzootic and epizootic of unprecedented size and

complexitycomplexity– 9 countries with ongoing outbreaks (most recently in Malaysia)9 countries with ongoing outbreaks (most recently in Malaysia)

Ongoing human cases with high case fatality, mostly in Ongoing human cases with high case fatality, mostly in healthy children and young adultshealthy children and young adults

Ongoing evolution of the virus’ antigenic, genetic and Ongoing evolution of the virus’ antigenic, genetic and functional propertiesfunctional properties

No sustained human to human transmission to dateNo sustained human to human transmission to date

Why are We Concerned?Why are We Concerned? Increasing countries/areas with avian influenzaIncreasing countries/areas with avian influenza

– Uncertainties on progress of controlUncertainties on progress of control

Ongoing human infection with avian H5N1Ongoing human infection with avian H5N1– Limited implementation of protective measuresLimited implementation of protective measures

Co-Circulating human influenza virusesCo-Circulating human influenza viruses– Risk of genetic reassortment leading to pandemic strainRisk of genetic reassortment leading to pandemic strain

Majority of human population would have no immunityMajority of human population would have no immunity H5N1 resembles the 1918-19 pandemic influenza in H5N1 resembles the 1918-19 pandemic influenza in

that healthy young persons are affected and a deadly that healthy young persons are affected and a deadly feature is a primary viral pneumonia.feature is a primary viral pneumonia.

Human InfectionsHuman Infections H5N1 - severe H5N1 - severe

– 1997 Hong Kong: 18 cases; 6 deaths 1997 Hong Kong: 18 cases; 6 deaths – 2003 Hong Kong: 2 cases; 1 death 2003 Hong Kong: 2 cases; 1 death – 2004 Vietnam and Thailand: 40 cases; 29 deaths2004 Vietnam and Thailand: 40 cases; 29 deaths– 2005 Hunan (China): 3 cases, 2 deaths2005 Hunan (China): 3 cases, 2 deaths

H9N2 - mildH9N2 - mild– 1999 Hong Kong: 2 cases (mild)1999 Hong Kong: 2 cases (mild)– 2003 Hong Kong: 1 case (mild) 2003 Hong Kong: 1 case (mild)

CIDRAP, 8/2005

17 Human Cases12 Deaths

94 Human Cases42 Deaths

4 Human Cases 4 Deaths

4 Human case 3 Deaths

Influenza H5N1: expanded host Influenza H5N1: expanded host range?range?

Domestic poultryDomestic poultry Wild birdsWild birds

– infectedinfected– reservoirreservoir

HumansHumans Swine (China)Swine (China) Cats? (Netherlands)Cats? (Netherlands)

The natural hosts of the influenza A virus

1968 2004

People 790 million 1.3 billion

Pigs 5.2 million 508 million

Poultry 12.3 million 13 billion

People, Pigs and Poultry in China

Understanding Pandemic InfluenzaUnderstanding Pandemic Influenza• Recent studies in mice using genetically Recent studies in mice using genetically

engineered influenza strains similar to the engineered influenza strains similar to the 1918 H1N1 pandemic strain suggest that 1918 H1N1 pandemic strain suggest that macrophage activities with high levels of macrophage activities with high levels of cytokine production maybe a factor in the cytokine production maybe a factor in the lung and other organ damage (cytokine lung and other organ damage (cytokine storm).storm). Kobasa et al; Nature 2004;431:703Kobasa et al; Nature 2004;431:703

• The clinical picture and epidemiology, as The clinical picture and epidemiology, as well as current studies of H5N1 cases in well as current studies of H5N1 cases in SE Asia suggest a similar “cytokine SE Asia suggest a similar “cytokine storm” phenomena.storm” phenomena. Peiris et al; Lancet 2004;363:617Peiris et al; Lancet 2004;363:617

Requirements for a PandemicRequirements for a Pandemic Isolation from humans of a novel influenza A Isolation from humans of a novel influenza A

virus virus Little or no immunity in the populationLittle or no immunity in the population Demonstrated ability of the virus to replicate Demonstrated ability of the virus to replicate

and cause diseaseand cause disease Efficient person-to-person transmissionEfficient person-to-person transmission

H5N1H5N1All prerequisites met for start of pandemic All prerequisites met for start of pandemic

except efficient human-to-human transmissionexcept efficient human-to-human transmission

More pathogenic than most avian strainsMore pathogenic than most avian strains– Progressively more pathogenic in poultryProgressively more pathogenic in poultry– Larger number of animal species affectedLarger number of animal species affected

Ducks are asymptomatic but excrete virus, so Ducks are asymptomatic but excrete virus, so sustainable reservoirsustainable reservoir

Pigs shown to be infected in ChinaPigs shown to be infected in China Human cases concentrated in previously Human cases concentrated in previously

healthy children and young adultshealthy children and young adults

National Level Command and National Level Command and Control for Pandemic InfluenzaControl for Pandemic InfluenzaLead Departments:Lead Departments:

Medical Response: Medical Response: DHHSDHHS

Veterinary Response: Veterinary Response: Dept. AgricultureDept. Agriculture

International Activities: International Activities: State DepartmentState Department

Overall domestic incident management and Overall domestic incident management and federal coordination is through the federal coordination is through the Department of Homeland SecurityDepartment of Homeland Security..

Criteria for success of initial controlCriteria for success of initial control Rapid identification of initial clusterRapid identification of initial cluster Rapid case detection, isolation, and treatmentRapid case detection, isolation, and treatment Rapid prophylaxis of targeted populationRapid prophylaxis of targeted population

– Sufficient drug availableSufficient drug available– No antiviral resistanceNo antiviral resistance

School and work closuresSchool and work closures Population cooperation with strategiesPopulation cooperation with strategiesAfter 4-5 weeks, it will be impossible to containAfter 4-5 weeks, it will be impossible to contain

Containing an Initial Outbreak of Containing an Initial Outbreak of Novel Influenza – Can this be done?Novel Influenza – Can this be done? Hong Kong accomplished this in 1997Hong Kong accomplished this in 1997 2004 H5N1 situation much more challenging2004 H5N1 situation much more challenging Large areas affected in a large number of countriesLarge areas affected in a large number of countries Slow and incomplete reporting of H5N1 findings Slow and incomplete reporting of H5N1 findings Poor public health infrastructure Poor public health infrastructure Complex political and economic situationsComplex political and economic situations International action required: support for antiviralsInternational action required: support for antivirals

WHO phase of Pandemic AlertWHO phase of Pandemic AlertPhase 1: Phase 1: Inter-pandemic phaseInter-pandemic phase: : Low risk of human casesLow risk of human casesPhase 2: Phase 2: New virus in animals, no human casesNew virus in animals, no human cases: Higher risk of human : Higher risk of human casescasesPhase 3: Phase 3: Pandemic Alert, New Virus causes human casesPandemic Alert, New Virus causes human cases: No or very : No or very limited human-to-human transmissionlimited human-to-human transmissionPhase 4: Phase 4: Pandemic Alert,Pandemic Alert, New virus causes human casesNew virus causes human cases: Evidence of : Evidence of increased human-to-human transmissionincreased human-to-human transmissionPhase 5: Phase 5: Pandemic Alert,Pandemic Alert, New virus causes human casesNew virus causes human cases: Evidence of : Evidence of

significant human-to-human transmissionsignificant human-to-human transmissionPhase 6: Phase 6: PANDEMICPANDEMIC: Efficient and sustained human-to-human : Efficient and sustained human-to-human transmissiontransmission

According to WHO, the world is presently in phase 3.According to WHO, the world is presently in phase 3.

WHO Outbreak Control MeasuresWHO Outbreak Control MeasuresPre pandemicPre pandemic PandemicPandemicPhase 4Phase 4 Phase 5Phase 5 Phase 6Phase 6

Confinement of casesConfinement of cases YesYes YesYes YesYes

Face masks Face masks

Symptomatic personsSymptomatic persons YesYes YesYes YesYes

Exposed personsExposed persons ConsiderConsider ConsiderConsider ConsiderConsider

Persons seeking carePersons seeking care YesYes YesYes YesYes

Tracing and follow up--contactsTracing and follow up--contacts YesYes YesYes NoNo

Voluntary quarantine--healthy contactsVoluntary quarantine--healthy contacts NoNo YesYes NoNo

Antiviral Prophylaxis--Contacts Antiviral Prophylaxis--Contacts YesYes YesYes NoNo

Voluntary home confinement of Voluntary home confinement of symptomatic personssymptomatic persons

YesYes YesYes YesYes

Closure of schoolsClosure of schools NoNo ConsiderConsider ConsiderConsider

Population-wide measures (e.g. close Population-wide measures (e.g. close workplaces)workplaces)

NoNo ConsiderConsider ConsiderConsider

U.S., State, and Local Control U.S., State, and Local Control MeasuresMeasures

Currently under developmentCurrently under development

Problems Anticipated in Surge Problems Anticipated in Surge CapacityCapacity

BedsBeds– Emergency regulations, increase in beds in existing Emergency regulations, increase in beds in existing

facilities, alternative facilities, tents, home carefacilities, alternative facilities, tents, home care PersonnelPersonnel

– Medical Reserve Corps; citizens volunteers; scope of Medical Reserve Corps; citizens volunteers; scope of practice changespractice changes

Equipment/Infection Control SuppliesEquipment/Infection Control Supplies Vaccine Vaccine MedicationsMedications

Vaccine Crisis• Current “standard” vaccine reflects 1950’s

technology– grown in chicken eggs– takes 6 months or more to produce– use of “reverse genetics” to develop prototype

vaccine virus

• Need an immediate and comprehensive international program to develop a cell culture system for vaccine production with surge capacity

Influenza Vaccine Crisis• Current annual international capacity for

influenza vaccine production using egg culture is approximately 300 million trivalent doses (900 million monovalent)

• Almost all of the world’s influenza vaccine is produced in nine countries (12% of the world’s population)

• Production capacity will NOT increase significantly in the next several years

• New and more timely methods for production are desperately needed and under investigation

Prototype VaccinePrototype Vaccine

Hungary has developed and tested a H5N1 Hungary has developed and tested a H5N1 vaccine on 150 personsvaccine on 150 persons

Claims it is effective “beyond doubt”Claims it is effective “beyond doubt” Set to be approved by European Medicines Set to be approved by European Medicines

Agency Agency Sold at $5-6 per doseSold at $5-6 per dose Ready to begin productionReady to begin production LIMITATION: In that vaccine must be developed LIMITATION: In that vaccine must be developed

based upon pandemic strain based upon pandemic strain

Advisory Committee Recommendation for Advisory Committee Recommendation for VaccineVaccine

Federal government should purchase all Federal government should purchase all influenza vaccine during a pandemicinfluenza vaccine during a pandemic

H5N1 Vaccine for U.S. StockpileH5N1 Vaccine for U.S. Stockpile Sanofi Pasteur $100 million for H5N1 Sanofi Pasteur $100 million for H5N1

vaccinevaccine Chiron 10,000 doses for testing Chiron 10,000 doses for testing HHS plans to buy vaccine for 20 millionHHS plans to buy vaccine for 20 million MedImmune developing multiple subtypesMedImmune developing multiple subtypes

Antiviral Stockpile (oseltamivir)Antiviral Stockpile (oseltamivir)Recommedations of Advisory GroupRecommedations of Advisory Group 40 million courses minimum40 million courses minimum

– 133 million courses to treat all infected and prophylaxis 133 million courses to treat all infected and prophylaxis HCWs and patients at highest risk of infectionHCWs and patients at highest risk of infection

Status of Antivirals for U.S. StockpileStatus of Antivirals for U.S. Stockpile Currently 2 million courses of TamifluCurrently 2 million courses of Tamiflu Orders for 6 million courses Orders for 6 million courses Plans for 20 million coursesPlans for 20 million courses GlaxoSmithKline $2.8 million for 84,300 treatment courses GlaxoSmithKline $2.8 million for 84,300 treatment courses

of zanamivir (Relenza)of zanamivir (Relenza) Request for funds to cover up to 50% of populationRequest for funds to cover up to 50% of population

Antivirals – Not A PanaceaAntivirals – Not A Panacea Global production capacity limited; high costGlobal production capacity limited; high cost Ability to use antivirals to limit spread depends on Ability to use antivirals to limit spread depends on

rapid case detection and contact tracing rapid case detection and contact tracing Need to start treatment earlyNeed to start treatment early Effectiveness on serious illnesses and mortality Effectiveness on serious illnesses and mortality

unknownunknown Prophylaxis may require ongoing use for 6 weeks or Prophylaxis may require ongoing use for 6 weeks or

longerlonger Antiviral resistance and side effects may limit useAntiviral resistance and side effects may limit use Tamiflu produced outside of U.S.Tamiflu produced outside of U.S.

Ten Things to Know About Ten Things to Know About Pandemic InfluenzaPandemic Influenza

1.1. Pandemic Influenza is different from Avian InfluenzaPandemic Influenza is different from Avian Influenza2.2. Influenza pandemics are recurring eventsInfluenza pandemics are recurring events3.3. The world may be on the brink of another pandemicThe world may be on the brink of another pandemic4.4. All countries will be affectedAll countries will be affected5.5. Widespread illness will occurWidespread illness will occur6.6. Medical supplies will be inadequateMedical supplies will be inadequate7.7. Large numbers of deaths will occurLarge numbers of deaths will occur8.8. Economic and social disruption will be greatEconomic and social disruption will be great9.9. Every country must be preparedEvery country must be prepared10.10. WHO will alert the world when the pandemic threat WHO will alert the world when the pandemic threat

increasesincreases

For the first time mankind is For the first time mankind is watching a potential pandemic watching a potential pandemic

unfolding.unfolding.

World Health Organization World Health Organization

alameda county influenza update

Documents

subtypes of influenza

virusesepidemics of

influenza type

distinct types of influenza

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subtypes of h h1

peoplethe high risk

handson care