Transcript Pandemic (H1N1) 2009 - Control Influenza Main

Pandemic (H1N1) 2009: The
Public Health Response
Dr. Sylvie Briand
Global Influenza Programme
WHO, Geneva
Faces of the Pandemic:
Old and New
Pandemic (H1N1) 2009 Overview
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As if 15 August 2010, 215
countries and territories have
reported cases
18,631 laboratory-confirmed
deaths in 125 countries
Official numbers significantly
underestimate actual
numbers
Widespread community
transmission in all areas
From April 2009 to August
2010
Pandemic Response Tools
PH measures (i.e. school closures, mask , mass gathering)
Non-pharmaceutical
Interventions
Cell-based
IIV
Inactivated Influenza Vaccine (IIV)
(1944)
Improved IIV
(1960 purified)
IIV
(2007)
(1980 sub-unit)
LAIV
(live-attenuated, 1960, Russia)
GISN
(1952)
1918
IIV
(1968 fragmented)
1957 1968
Asian flu
pandemic
Spanish flu
pandemic
Hong Kong flu
pandemic
Adjuvanted
IIV
Vaccines
LAIV
(2003, USA)
(1997)
1997
2003
H5N1
Hong Kong
18 Cases (C)
6 Deaths (D)
H5N1
Asia
504 C
299 D
2009
A (H1N1) 2009
pandemic
Rimatadane
Amatadane
for influenza (1966)
(1993)
Neuraminidase inhibitor
Antivirals
Oseltamivir and Zanamivir (1999)
Aminoglycosides Erythromycin
(1943)
Sulfonamides Penicillin
(1939)
(1945)
Antibiotics
(1952)
Cephalosporins
(1964)
Introduction of other classes of antibiotics
Pandemic Response Tools
Virus and benefit sharing
discussion (2007) PIP OEWG
Revision of International Health Regulations
(IHR) (1969)
• Plague
• Yellow fever
• Cholera
1918
Spanish flu
pandemic
1957 1968
Asian flu
pandemic
Hong Kong flu
pandemic
1997
H5N1
Hong Kong
18 C
6D
Pandemic
Preparedness
Guidelines
(1999):
3 phases
IHR revision
Includes all Public Health
Emergencies of
International Concern
(PHEIC) (2005)
2003
SARS
Global
>8000 C
774 D
2009
H5N1
Asia
504 C
299 D
PP guide
(2005):
6 phases
A(H1N1) 2009
pandemic
PP guide
(2009):
6 phases
Assessment
of Severity Characteristics
Source: Weekly Epidemiological Record, 13 November 2009.
Infection and Disease
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Broad clinical spectrum of
disease
– High proportion of pauci or
asymptomatic
– 10-50% of GI symptoms
– Severe viral pneumonia in
healthy adults
– 10-20% of hospitalizations
required ICU
Groups at increased risk of
severe disease once infected
(hospitalization, ICU, death)
– Chronic medical conditions
– Pregnant women
– Very young and the elderly
– Obese
– Aboriginal/ethnic minorities
– 40% were previously healthy
Highest rates of clinical
infection:
Teens and young adults
Highest rates of hospitalization:
Children < 5 (median
age 20s-30s)
Highest rates of death:
Adults 50-64 (median
35-51; younger age
group compared to
seasonal influenza)
How is this pandemic different?
– First large scale response under the revised
International Health Regulations (2005) framework
– Global sharing of information and viruses through
expert networks
• E.g. Virus sharing: As of 5 May 2010, 155 countries shared 26,066
specimens with WHO Collaborating Centres
– Significant, previous pandemic preparedness efforts,
incl. the area of risk communication
• E.g. 140 countries with pandemic preparedness plans before the
pandemic
– Access to
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antibiotics
antiviral
vaccines (developed and available in 6 months)
high-quality health care (i.e. ICU)
– Early detection and response at international level
• E.g. Virus sequence made publicly available on 25 April 2009
• RT-PCR kits available on 2 May 2009
Spread of Pandemics
• 1957: Spread throughout China in 6 weeks
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and throughout the world in 6 months
2009-2010: Started in North America; spread
to all continents in less than 9 weeks and
throughout the world in 10 months
– Announcement of pandemic phase 6 on 11
June 2009
• 74 countries reporting cases of (H1N1) 2009 virus
– West Africa reported A (H1N1) pandemic
outbreaks only in early 2010
Continued Global Spread of H1N1
April 2009 - February 2010
April 2009
September 2009 (5 months)
May 2009 (1 month)
December 2009 (8 months)
July 2009 (3 months)
February 2010 (10 months)
Proposed 2009 Phases Structure
and Pandemic Disease "Risk"
Geographic spread
5-6
Predominantly animal
infections;
Limited transmissibility
among people
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Sustained
human-to-human
transmission
Rapid
1-3
containment
Time
Post
Peak
Post
Pandemic
Early Responses to
the Pandemic
• No travel restrictions.
• Attempt to contain the spread with societal
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measures (e.g. school closures or antiviral
prophylaxis in close communities).
More information is needed to assess the
impact and cost effectiveness of the various
strategies.
Molecular Evolutionary Analysis of the Influenza A (H1N1) pdm, May–September, 2009: Temporal and
Spatial Spreading Profile of the Viruses in Japan. (Shiino T et al. PLoS ONE 1 June 2010, Vol. 5:6)
School closure: 16 May – 5 June (Kobe prefecture)
Source: Infectious Agents
Surveillance Report, 2009
Time
course of
the H1N1
pandemic
for select
countries*
Peak(s) (N.B. Not all countries have detected a "peak" in activity )
Cases detectedCases detected
Sporadic Cases
Sporadic Cases Detected
Detected
Peak(s)**
Data sources vary
by country and
include: countryprovided epi curves
of case onset; ILI
consultation rates;
Virus isolates by
date; percentage of
positive specimens
collected; media
source (first case
report for some
countries).
*Table developed by: Maria Van Kerkove PhD, MRC Centre for Outbreak Analysis and Modeling, Imperial College London
** N.B. Not all countries have detected peak inactivity.
Global Spread of Pandemic (H1N1)
2009, Co-circulation of Viruses
Challenges
Surveillance and Severity
Assessment
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Severity assessed and monitored with a basket of indicators
– 3 dimensions:
• Severity of the disease (clinical epidemiological and virological)
• Vulnerability of the population
• Capacity to respond
During the pandemic, the heterogeneity of systems and
indicators has been a major challenge for global monitoring
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Different age groups
No standardized definition of underlying factors
No standardized definition of Influenza deaths
Different laboratory capacity
More than 100 countries have very limited or no influenza
surveillance capacity
Phases in Preparedness Guidelines
2009 version
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Since 1999, pandemic phases have been used as a tool for
planning pandemic responses at global and country levels.
Pandemic phases were never used during a pandemic.
Main challenge: Publication of new guidelines in early 2009
presented a communications challenge, namely helping the
media and Member States (MS) understand the meaning of the
phases.
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Communications
The first phase went well: Early announcement,
transparent communication
Then things started to unravel: Conspiracy theories
started to spread in media and through networks on the
internet
The consequences were :
– Misunderstanding of the public health response from the
general public and low uptake of vaccine in some countries
– A number of parliamentary enquiries and external reviews of
technical agencies' responses to the pandemic
New sources of information dissemination have to be taken
into account in future pandemic preparedness plans: internet,
blogs, virtual social networks
Naming of the Pandemic
Global Health Challenges
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International mass gatherings (Hajj, FIFA World
Cup, Vancouver Olympics)
Global solidarity
– Access to antivirals
• Deployment to 72 countries
– Access to pandemic vaccines
• Deployment started in
November 2009
• As of 30 August 2010,
reached 72 countries
• 73 million doses
Concluding Observations
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Certain events were correctly anticipated
– Eventual emergence of a pandemic
– Spread was more rapid than in the past
Certain events theoretically acknowledged, but still
a surprise
– Started in North America
– Origin of pandemic virus came from swine H1 viruses
Certain events were simply surprising
– Effectiveness of one vaccine dose
Preparedness was crucial but remains incomplete
Impact of control measures on the spread and
severity of the disease are being assessed
Acknowledgments
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Hundreds of people have contributed to the global
response to the pandemic (H1N1) 2009
– Global Influenza Programme and WHO regional
offices
– Technical partners, including national CDC, ECDC,
national influenza centres of GISN, WHO CC and
academia
– Professionals at country level participating in
technical networks (Ministries of Health, Public health
agencies)
Thank you
谢谢
Merci
Gracias