Post on 05-Jan-2016
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Situation UpdateInfluenza A (H1N1), 26 May 09
Situation UpdateInfluenza A (H1N1), 26 May 09
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Age distribution of confirmed new influenza A (H1N1) cases in Mexico and United States, 2009 (cases reported to 12 May)
Age distribution of confirmed new influenza A (H1N1) cases in Mexico and United States, 2009 (cases reported to 12 May)
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Cumulative No. of cases and countries reporting Influenza A (H1N1)
0
5
10
15
20
25
30
35
40
45
50
Date of report
No
of c
ount
ries
rep
ortin
g
0
2000
4000
6000
8000
10000
12000
14000
Num
ber
of c
onfir
med
cas
es
Public health emergency of international concern
Pandemic Phase 4
Pandemic Phase 5
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Reasons for concern about Influenza A (H1N1)
Reasons for concern about Influenza A (H1N1)
New strain- combination of swine-avian-human influenza viruses
Evidences for sustained human-to-human infection – cases with no evidence of exposure other than infected humans
(most cases reported so far)– clusters of cases in family members (USA, Mexico)
Young people; median age of cases: 22 years
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Influenza A (H1N1): VirologyInfluenza A (H1N1): Virology
Reassortment - four different genes:– North America swine– Asia/Europe swine– Human influenza– Avian (Non H5)
Unique combination that has never been seen before
Level of immunity in general community – Unknown, probably limited or none
Effectiveness of seasonal influenza vaccine– Unknown
Antiviral resistance– Resistant to amandatines– Sensitive to oseltamivir (tamiflu) and zanamivir (relenza)
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Pandemic Phases Pandemic Phases
1 - 3
SustainedH-2-H
transmission
Time
Predominantly animalinfections; Limited infections of people
Geographic spread
5 - 6
4
PostPeak
PostPandemic
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Phase 5Phase 5
Phase 5 is characterized by the same identified virus that has caused sustained community level outbreaks into at least two countries in one WHO region.
the declaration of Phase 5 is a strong signal that a pandemic is imminent
the time to finalize the organization, communication, and implementation of the planned mitigation measures is short;
Each country should implement actions as called for in their national influenza pandemic preparedness plans.
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Phase 5 to Phase 6Phase 5 to Phase 6
Phase 6 is characterized by community level outbreaks in at least one other country in a different WHO region by the same virus
Designation of this phase will indicate that a global pandemic is under way.
Means expansion to newer area not an indication of it’s severity
Member countries should review surge capacity and emphasize measures to reduce the spread of disease
Surge capacity: in the area of surveillance, rapid detection, lab diagnosis, hospital and health centres, community awareness and empowerment etc.
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Lesson learned so far…Lesson learned so far…
Past experiences show influenza viruses spread fast and far (such as seen in 1918, 1957, 1968)
Pandemic influenza may be observed in several waves, i.e. milder form to severe form
Need to review Pandemic Preparedness Plan which were developed with AI (H5N1) in mind; H5N1 still around
Miscommunication and misinterpretation of the events are a real challenge, i.e. travel ban, culling of pigs, import ban and remove pork from menu
Knowledge gaps exist on current pandemic from novel influenza A (H1N1)- as it is evolving
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Influenza SeasonalityInfluenza SeasonalityInfluenza SeasonalityInfluenza Seasonality
0
4
8
12
16
20
24
28
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Winter Summer Rainy Season
Pune (west)
0
4
8
12
16
20
24
28
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Winter Summer Rainy Season
Kolkota (east)
-1
3
7
11
15
19
23
27
31
35
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Summer Winter Rainy Season
Chennai (south)
0
4
8
12
16
20
24
28
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Winter Summer Rainy Season
Delhi (north)
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WHO/SEARO Response WHO/SEARO Response
Situation monitoring and assessment
Technical guidance
Capacity building: surveillance and laboratory diagnosis
Vaccine and antivirals
Communication– media briefing, interviews, web updates etc
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Visit us at: http://www.searo.who.int/h1n1