Transcript Slide 1

Influenza A H1N1: A Pandemic in
Real Time – What’s Next?
Danny Chen, MD FRCPC MSc
Infectious Disease Specialist
Grand Rounds, York Central Hospital
September 9, 2009
SEX
Genetic origins of the pandemic (H1N1) 2009
virus: Quadruple viral reassortment
N. American H1N1
(swine/avian/human)
PB2
PB1
PA
HA
NP
NA
MP
NS
Eurasian
swine H1N1
PB2
PB1
PA
HA
NP
NA
MP
NS
Classical swine, N. American lineage
Avian, N. American lineage
Human seasonal H3N2
Eurasian swine lineage
PB2
PB1
PA
HA
NP
NA
MP
NS
Pandemic (H1N1)
2009, combining
swine, avian and
human viral
components
WHO phases of pandemic alert
Symptoms
• Definition of Influenza-like Illness (ILI):
– Acute onset fever and cough
AND
– one or more of:
• Sore throat, arthralgia, myalgia, or prostration,
– In children < 5 years of age, GI symptoms
may also be present.
– In patients < 5 years of age or >65 years fever
may not be prominent.
Guidance for Management of Patients with Influenza-like Illness
(ILI) in Emergency Departments, MOHLTC June 4, 2009
Transmission
Prevention
ENHANCED
DROPLET
PRECAUTIONS
– Hand hygiene always
– Gown, gloves, eye protection, N95 mask
= droplet + contact + N95
Treatment Recommendations
• Oseltamivir
recommended within 48
hours of the onset of
symptoms:
– ILI requiring hospitalization
OR
– ILI and at risk for
complicated disease
• Other patients with ILI do
not require treatment.
Laboratory confirmed cases of pandemic (H1N1) 2009 in
Ontario by week between April 13 and August 29, 2009
Hospitalizations among confirmed cases of pandemic
(H1N1) 2009 in Ontario, April 13 – September 3, 2009
Incidence of hospitalization and death due to
pH1N1 in Ontario, April 13 to September 3, 2009
Seasonal influenza
• Every year:
• 5 million Canadians (1 in 6) will be infected
– Up to 75,000 hospitalized
– 2000-4000 people will die
• 90% are >65 yrs
– half of those in LTCHs
• Bacterial pneumonia
• Cardiac failure
Mortality rate:
13/100,000
population
0.2% of cases
PANDEMIC H1N1 2009
CASES AT YCH
Number
Seen in ER and
discharged
24
Hospitalized
15
TOTAL
39
So What Next
“Potential for catastrophe…”
vs
“…a pandemic dud.”
Laboratory confirmed cases of pandemic (H1N1) 2009
in Australia, to 28 August 2009 by
jurisdiction
Rate of ILI reported from GP ILI surveillance systems
from 2007 to 23 August 2009 by week
Rates of absenteeism of greater than 3 days absent,
National employer, 1 January 2007 to
19 August 2009, by week
Hospitalised confirmed cases of pandemic (H1N1)
2009, by length of hospital stay and age
group, to 28 August 2009, Australia
Age specific rates of hospitalised confirmed cases of
pandemic (H1N1) 2009 compared with average annual
age specific rates of hospitalisations from seasonal
influenza, Australia
Hospitalized (n= 1145)
Comorbidity
64% (731)
chronic respiratory
diabetes
pregnancy
chronic cardiac
immunocompromised
morbid obesity
renal
51% (n=379)
14% (n=107)
11% (n=77)
11% (n=84)
11% (n=77)
8% (n=57)
5% (n=35)
Hospitalised confirmed cases of pandemic (H1N1) 2009
in pregnant women by weeks of
gestation, to 28 August 2009, Australia
Numbers of deaths among confirmed cases of
pandemic (H1N1) 2009, by age group and
sex, compared with total laboratory confirmed
pandemic (H1N1) 2009 notifications by age group
Median age = 54 (cf seasonal flu: 83yo)
Percentage of all deaths classified as influenza and
pneumonia, WA Registry of Births,
Deaths and Marriages, 1 January 2008 to 23 August 2009
Seasonal
Flu
Similar
Pandemic H1N1
2009
Similar
Transmission
Same
Same
Prevention
Same
Severity
Similar
Same
(enhanced droplet)
Similar
Older (>65)
Younger
Symptoms
Age affected
But no room for complacency
• Pandemics take some time to get going (1918 and
1968).
• Some pandemic viruses have ‘turned nasty’ (1918
and 1968).
• There will be severely ill people and deaths — in risk
groups (young children, pregnant women and
especially people with underlying illnesses).
• Health services capacity?
• Resistance to antivirals?
• Attack rate?
• An inappropriate and excessive response to the
pandemic could be worse than the pandemic itself…
“…the H1N1 influenza and influenza
generally is unpredictable...”
Dr. Anne Schuchat, CDC
Pandemic Model
York Region Impact
• 35% of the population, including YCH staff,
will be infected during the first wave of
pandemic influenza
• Need to MAXIMIZE CAPACITY to
manage increased patient volumes in the
face of depleted resources
Summary
• H1N1 now the dominant virus strain
• Large populations susceptible to infection
– Vaccine?
• Not the same as seasonal influenza
– Age distribution
• Influenza is unpredictable
• Be prepared
– Capacity, resources
Summary
• What next…
– Replay the Australian
experience?
•
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