03 Pandemic Influenza

8/7/2019 03 Pandemic Influenza

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Pandemic Influenza


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Influenza is usually a respiratoryinfection

TransmissionRegular person-to-person transmission

Primarily through contact with respiratorydroplets

Transmission from objects (fomites)possible


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Transmission of Influenza Limited studies, varying

interpretations

Contact, droplet, and droplet nuclei

(airborne) transmission all likelyoccur

Relative contribution of eachunclear

Droplet thought most important Coughing, sneezing, talking

Most studies either Animals or human experiments

under artificial conditions Outbreak investigations

Unclear of infection source


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Key Characteristics

Communicability

Viral shedding can begin 1 daybefore symptom onset

Peak shedding first 3 days ofillness

Correlates with temperature Subsides usually by 5-7th day

in adults

can be 10+ days in children

Infants, children and theimmunocompromised mayshed the virus longer


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Incubation period Time from exposure to onset of symptoms

1 to 4 days (average = 2 days)

Seasonality

In temperate zones, sharp peaks in wintermonths

In tropical zones, circulates year-round with

seasonal increases.


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Clinical Illness, Seasonal

Influenza Abrupt onset

Fever and constitutional symptoms: bodyaches, headaches, fatigue

Cough, rhinitis, sore throat

GI symptoms and myositis more common inyoung children

Sepsis-like syndrome in infants

Complications: viral and bacterial pneumonia,febrile seizures, cardiomyopathy,encephalopathy/encephalitis, worsening

underlying chronic conditions


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Vaccination

Influenza vaccine is the best prevention forseasonal influenza.

Inactivated viruses in the vaccine developed fromthree circulating strains (generally 2 Type A and 1

Type B strain)

Therefore, seasonal flu shot only works for 3 influenzasubtypes and will not work on pandemic strains.

Live, intranasal spray vaccine for healthy non-

pregnant persons 5-49 years Inactivated, injectable vaccine for persons 6

months and older


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Non-Pharmaceutical Interventions

Voluntary isolation of sick people

Voluntary quarantine of healthy contacts School closures

Social distancing


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Avian Influenza


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Avian Influenza

Type A influenza Endemic in birds

H5, H7 subtypes can cause seriousdisease or death in wild birds; oftencause death in poultry

Virus in saliva and feces of wildbirds and poultry can be directlytransmitted to humans and otheranimals

Can contaminate clothing,equipment, water, feed


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H5N1 Avian Influenza Currently spreading through Asia, Africa,

Europe, Middle East Can be highly lethal to domestic poultry and

other animal species

Occasional human cases but no efficient humanto human transmission yet

Virus of greatest concern for pandemic potential,

but other viruses in animals also of concern

*As of March 8, 2007


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Characterized by ability to change Continually yearly epidemics

Drastically sporadic pandemics

Influenza Viruses


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Influenza Viruses Classified into types A, B, and C

Only Types A and B cause

significant disease Types B and C limited tohumans

Type A viruses More virulent Affect many species

C Goldsmith, CDC


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Influenza A Viruses Influenza A viruses categorized by subtype

Classified according to two surface proteins

Hemagglutinin (H) 16 known Site of attachment to host cells Antibody to HA is protective

Neuraminidase (N) 9 known Helps release virions from cells Antibody to NA can help modify disease severity

N

H


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A / Sydney / 05 / 97 (H3N2)

Nomenclature

Virus type Strain number Virus subtype

Place virus

isolated

Year isolated


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H5N1 in Other Animals

H5N1 can infect otheranimals:

Pigs (China, Vietnam) Dogs

Domestic cats; has

infected civet cats

Tigers, leopards(Thailand, China)

Tiger-to-tigertransmission (Thailand)


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Avian Influenza Low pathogenic AI (LPAI)

Most common influenza infection in birds Causes mild clinical and unapparent infections

May be any subtype (H1 to H15)

Highly pathogenic AI (HPAI) Some H5 or H7 subtypes

Causes severe illness in poultry and often death

LPAI H5 or H7 subtypes can mutateinto HPAI H5 or H7 subtypes


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Migratory

water birds

Domestic birds

Avian influenza

United Kingdom Department of Health

All known Influenza Asubtypes

Circulate in wild birds&

Infect domestic birds.

Wild birds =Reservoir for Influenza A strains

&source for viruses infecting other

species.


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H5N1 Epizootic 2003-2006

Since December 2003, >50 countries have

reported H5N1 amongdomestic poultry and wildbirds

Current outbreaks in a

many countries Expanded from Asia to the

Middle East, Europe, andAfrica

Largest epizootic of avianinfluenza ever described Over 200 million birds died

or destroyed


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H5N1 Clinical Features Case fatality ratio: 60% Median age: 20 years (range 3 mos-75

yrs)* Previously healthy children, young adults

Incubation: 2-8 days

Fever, cough, shortness of breath,diarrhea

Pneumonia, severe respiratory disease Leukopenia, multisystem organ failure

Beigel JH, et al. NEJM 2005;353:1374-85 *WHO WER;26:249-260


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Clinical illness with H5N1

compared with typical humaninfluenza illness

More severe illness in younger persons

Primary viral pneumonia appears to bemore common and with rapid onset

Incubation period may be longer Duration of infectious period likely longer,

particularly among adults


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Avian Influenza in HumansYear Subtype Location Cases Deaths

1996 H7N7 United Kingdom 1 0

1997 H5N1 Hong Kong 18 61998 H9N2 China 6 0

1999 H9N2 Hong Kong 2 0

2002 H7N2 United States 1 02003 H7N2 United States 1 0

2003 H9N2 Hong Kong 1 0

2003 H5N1 Hong Kong 2 12003 H7N7 The Netherlands 89 1

2004 H7N3 Canada 2 0

2003-07 H5N1 Worldwide 281* 169* As of March 21, 2007


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H5N1 Possible Travel Routes

Legal poultry business

Illegal bird trade

Untreated fertilizer

Migrating birds

Humans (contaminated

objects)


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HumanHumanvirusvirus

ReassortantReassortant

virusvirus

NonNon--humanhuman

virusvirus

Re-assortment and

Direct Transmission

DIRECTDIRECT


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What is Pandemic Influenza?What is Pandemic Influenza? Pandemic: epidemic spreadingPandemic: epidemic spreading

around the world affecting hundredsaround the world affecting hundreds

of thousands of people, acrossof thousands of people, acrossmany countriesmany countries

Flu pandemics: global influenzaFlu pandemics: global influenza

epidemics of newly emerged strainepidemics of newly emerged strain

of influenza thatof influenza that

passes easily from person to personpasses easily from person to person

causes severe diseasecauses severe disease

Essentially no preEssentially no pre--existing immunity;existing immunity;

every body at riskevery body at risk


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Influenza Pandemic VirusesRequirements:

A new influenza A subtype can infect humansAND

Causes serious illness

AND

Spreads easily from human-to-human

The first two prerequisites have been met,

but not the last

Each new human infection is an opportunity for thevirus to change


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Pandemic InfluenzaPandemic Influenza

Timing unpredictableTiming unpredictable

High illness rates across age groupsHigh illness rates across age groups

Increased mortalityIncreased mortality

Higher proportion deaths in youngerHigher proportion deaths in youngerpersonspersons


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Estimated Mortality fromInfluenza Pandemics

1918-19 (H1N1)>500,000 deaths US20 -100 million worldwide

1957-58 (H2N2)70,000 deaths US

1968-69 (H3N2)34,000 deaths US

C b t P d i


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Concerns about Pandemic

Influenza Rapid global spread (morbidity and mortality)Rapid global spread (morbidity and mortality)

Shortages and delaysShortages and delays vaccines and antiviralvaccines and antiviralmedicationsmedications

Increases burden on hospitals and outpatientIncreases burden on hospitals and outpatientcare systemscare systems

Disrupts national and community infrastructuresDisrupts national and community infrastructures


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Inter-species Transmission

and Pandemics Many reports of transmission animal

influenza viruses to humans that do notresult in pandemic E.g. Swine Flu 1976

230 infected, 13 hospitalized, 1 death No sustained transmission beyond Ft. Dix, NJ

But, because pandemics may be so

devastating, vigilance and planning critical


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WHO Stages of a Pandemic Inter-pandemic period

Pandemic alert period

Pandemic period

Post pandemic period


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WHO Phases of a PandemicInter-pandemic Period

Phase 1: No new Influenza virus subtypes in

humans

Phase 2: No new virus subtypes in humans;animal subtype poses a risk of humandisease


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Pandemic Alert Period

Phase 3: Human infection with novel virus;no instances of human-to-human spread

Phase 4: Small, localized clusters of human-to-human spread

Phase 5: Larger clusters, still localized; virusadapting to humans

WHO Phases of a Pandemic


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Pandemic Period

Phase 6: Increased and sustainedtransmission in the general population.

Post Pandemic Period

Recovery phase

WHO Phases of a Pandemic


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Possible Scenarios in the Philippines

No avian influenza in birds, thus no bird-to-human transmission

Avian influenza in birds, bird-to-humantransmission

Avian influenza in birds, bird-to-humantransmission, human-to-humantransmission

No avian influenza in birds, human

cases from other countries due to novelvirus


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Non-pharmaceutical interventions (NPIs)

Measures other than vaccines and antivirals that

may reduce the risk of transmission of a influenzato individuals and communities

NPIs can be implemented at borders, or at the

level of the community and the individual


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Wh NPI b i


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During the first few months after a pandemic

begins: Vaccine made from a pandemic strain will probablynot to be available

Antivirals may be insufficient in quantity, ineffective

and/or difficult to distribute in a timely way In many countries of the world, it may be some

time before either vaccine or antivirals areavailable in sufficient quantity

Why are NPIs being

considered?


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E l f ibl


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Examples of possible

consequences of school dismissal Families

Children Missed school/disruption of education

School-meal dependent children lose meals, nutrition

Happy not to have to go to schools

More time with friends

Parents Missed work/lost income

Childcare

Intangible costs (e.g., stress)

E l f ibl


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Examples of possible

consequences of school dismissal Communities

Lost productivity due to work absenteeism Industries that support school functioning

lose business (e.g., school meal industry)

Additional transmission caused by childrenre-congregating


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Other Prevention Strategies Community

International ports of entry Individuals


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CDC Quarantine Stations


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Possible screening measures* Traveler questionnaire and/or interview

Visual inspection

Fever screening (temperature check) Specimen collection and testing (secondary)

*Effectiveness unknown; dependent on clinical syndrome

and other factors (e.g. time of flight)

CDC Quarantine Stations

Ports of entry NPIs


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Infection Control Measures All interventions should be used in

combination with infection control measuresincluding:

Hand hygiene

Cough etiquette

Environmental cleaning

Personal protective equipment such as facemasks

Maintaining essential servicesMaintaining essential services


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Persons providing

Emergency and disaster response

Maintenance of peace and order

Transportation, including air traffic controllers Utilities water, electricity

In an explosive spread, efforts and resourceswill be shifted to maintenanceof essential services

Arrange ahead places of duties and schedule toArrange ahead places of duties and schedule to

cover the required duties during the pandemiccover the required duties during the pandemic

Back upBack up

Maintaining essential servicesMaintaining essential services

C i ith i d d d f h lthC i ith i d d d f h lth


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manpower augmentation antipyretics, analgesics, liniments andantibiotics for home care

triaging of cases in out-patient clinics

Shortage of beds, equipment and supplies Only serious and urgent cases will be

admitted Back-up / buddy system Supplies of relevant drugs (e.g.

antibiotics) and equipment (e.g. Ventilator)

Secondary and tertiary care

Coping with increased demand for healthCoping with increased demand for health

services and goodsservices and goodsPrimary care


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What is the DOH doing?What is the DOH doing?


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Establishment of unified private sector network, primarily the civilsociety organization and the business sector

Capability building of key people from the central and regionaloffices of DA, DOH and DENR and of Agricultural and HealthOfficers in 20 critical sites covering 103 municipalities

Consultative Forum for DOH Regional Coordinators on SARS, AI &Other Emerging Infectious Diseases Provided the trained trainors with updates from DOH and DA

Obtained feedback from the participants on their field experiences Gathered baseline information from the core trainors on the impact of

TOT & the previous regional training series for processing throughSWOT analysis

Presentation of the revised course outline

Finalization of the regional action plan

What has been accomplishedWhat has been accomplished


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Training of DOH-retained and selected local

hospitals Regional Training Series

Fighting a Pandemic: Training of LGUs onPreparedness for SARS, Avian Influenza and OtherEmerging Infectious Diseases

Aimed to build the capacity of PHOs / MHOs / CHOs in AI /SARS / EID preparedness and response

Development and dissemination of informationon avian influenza



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Ban importation of poultry and its products fromBan importation of poultry and its products from

AIAI--affected countriesaffected countries Assist Local Government Units (Assist Local Government Units (LGUsLGUs) in) in

drafting their Preparedness and Response Plansdrafting their Preparedness and Response Plans

Conduct AIPP lectures and AI updates toConduct AIPP lectures and AI updates torequesting parties & concerned groupsrequesting parties & concerned groups

Assessment of prior surveillance work andAssessment of prior surveillance work and

institutionalization of surveillance activitiesinstitutionalization of surveillance activities



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Orientation of Barangay Health

Emergency Response Teams on AvianInfluenza

Aimed at orienting the BHERTS on Avian

Influenza

Provision of PPEs to CHDs & DOHretained hospitals designated as AIreferral hospital



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Moving ForwardMoving Forward Conduct of simulation exercises as teaching, planning

and assessment tools

Expansion of the information campaign to the localcommunities through a collaborative effort of the publicand the private sector

Continuing efforts for strengthening of surveillance of

birds and humans Capacity building of DOH-retained and local hospitals forresponse to serious infectious disease disasters

Strengthened participation of other government agenciesand the private sector for avian and pandemic influenzapreparedness


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Continuing efforts to prepare the public healthand hospital systems for avian and pandemicinfluenza that could further lay the foundation tostrengthen preparedness to any severeemerging infectious disease

Training of more Municipal Agricultural andHealth Officers for Avian and PandemicInfluenza from 1200 municipalities

Training of Barangay Health EmergencyResponse and Rapid Action Teams Pilot testing of the Early Warning System

Moving ForwardMoving Forward


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Moving ForwardMoving Forward Conduct of real time simulation exercises to testConduct of real time simulation exercises to test

the AIPPthe AIPP

Expanding areas for disease surveillanceExpanding areas for disease surveillance Intensification of IEC campaign in the twentyIntensification of IEC campaign in the twenty

(20) critical areas for AI, international borders(20) critical areas for AI, international borders

and coastlinesand coastlines


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Moving ForwardMoving Forward Review of the AIPP for further improvement of

disease control and eradication protocols

Training of more military men and volunteers forimmediate response in the event of an outbreak

Establishment of AI laboratories in Luzon,

Visayas and Mindanao to complement activitiesof the National Influenza Center (RITM)


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Critical in averting a potentialpandemic:

Early Recognition

and Containment

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03 Pandemic Influenza

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