who pandemic phases interpandemic period phase 1 phase 2 pandemic alert period phase 3 phase 4 phase...

WHO PANDEMIC WHO PANDEMIC PHASESPHASES

INTERPANDEMIC PERIOD

Phase 1

Phase 2

PANDEMIC ALERT PERIOD

Phase 3

Phase 4

Phase 5

PANDEMIC PERIOD

Phase 6

POSTPANDEMIC PERIOD

INFLUENZA VIRUS

MILESTONES IN INFLUENZAMILESTONES IN INFLUENZA

1933 Demonstration of virus transmission to ferrets Smith et al. 1933

1937 Growth of influenza virus in hens’ eggs Francis & Magill 1937

1941 Agglutination of erythrocytes by influenza Hirst 1941

1943 Extensive clinical trials in USA showed vaccine was 70% effective Francis 1943

1945 Vaccination of US Army showed consistent protection Francis et al. 1946

1945 Licence of first influenza vaccine in USA

I cannot forecast to you the action of Russia. It is a riddle wrapped in a mystery inside an enigma.

Sir Winston ChurchillRadio Broadcast, October 1, 1939

I cannot forecast to you the pandemic impact of this influenza virus. Influenza virus is a riddle wrapped in a haemagglutinin – neuraminidase encrusted envelope inside an enigma

Barry D SchoubNICD, June 22, 2009

A.A. SPORADIC INFLUENZASPORADIC INFLUENZA

B.B. PANDEMIC INFLUENZAPANDEMIC INFLUENZA

C.C. SEASONAL INFLUENZASEASONAL INFLUENZA

HUMAN CASES OF AVIAN INFLUENZA

Year Subtype No. of Cases Location

1997 H5N1 18 (6 deaths) Hong Kong

1999 H9N2 2 (children ages 4 yr, 13 mo) Hong Kong

2002 H7N2 1 United States (Virginia)

2003 H5N1 2 (1 death) Hong Kong

2003 H7N7 89 (1 death) The Netherlands

2003 H7N2 1 New York

2003 H9N2 1 (child) Hong Kong

2003- (ongoing)

H5N1 262/440 (60%) Vietnam, Thailand, Cambodia, Indonesia, China, Turkey, Iraq, Azerbaijan, Egypt etc

2004 H7N3 2 Canada (British Columbia)

2004 H10N7 2 (infants) Egypt

NICD

INFLUENZA PANDEMICSINFLUENZA PANDEMICS

15101510 1889 – 18901889 – 1890 H2N2H2N2 1899 – 19001899 – 1900 H3N2H3N2 1918 – 19191918 – 1919 H1N1H1N1 “Spanish flu” “Spanish flu” 1957 – 19581957 – 1958 H2N2H2N2 “Asian flu” “Asian flu” 1968 – 19691968 – 1969 H3N2H3N2 “Hong Kong flu” “Hong Kong flu”

NICD

INFLUENZA PANDEMICS

15101510 1889 – 18901889 – 1890 H2N2H2N2 1899 – 19001899 – 1900 H3N2H3N2 1918 – 19191918 – 1919 H1N1H1N1 “Spanish flu” “Spanish flu” 1957 – 19581957 – 1958 H2N2H2N2 “Asian flu” “Asian flu” 1968 – 19691968 – 1969 H3N2H3N2 “Hong Kong flu” “Hong Kong flu”

NICD

1977 H1N1

RECOMMENDED VACCINE RECOMMENDED VACCINE FORMULATIONFORMULATION

The following strains have been recommended by the WHO for the 2009 Southern Hemisphere influenza season:-

A/Brisbane/59/2007 (H1N1) - like virus *

A/Brisbane/10/2007 (H3N2) - like virus **

B/Florida/4/2006 - like virus #

* A/South Dakota/6/2007 (an A/Brisbane/59/2007-like virus) is a current vaccine virus used in live attenuated vaccines** A/Brisbane/10/2007 and A/Uruguay/716/2007 (an A/Brisbane/10/2007-like virus) are current vaccine viruses# B/Florida/4/2006 and B/Brisbane/3/2007 (a B/Florida/4/2006-like virus) are current vaccine viruses

ONSET & DURATION OF INFLUENZA ONSET & DURATION OF INFLUENZA SEASON: 1985 - 2007SEASON: 1985 - 2007

Median onset:Median onset: Week 23Week 23 Range 15-28Range 15-28

Median peak:Median peak: Week 27Week 27 Range 20-32Range 20-32

Median Median duration:duration: 10 weeks10 weeks Range 7-17Range 7-17

Epidemiological week

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

19851986

198719881989

19901991

19921993

1994

19951996

19971998

1999

20002001

200220032004

2005

2006

Mean onset

2007

Apr May Jun Jul Aug Sep

INFLUENZA VIRUS

(9 subtypes)

(16 subtypes)

NICD

HAEMAGGLUTININSHAEMAGGLUTININS H1H1 N1N1 NEURAMINIDASESNEURAMINIDASES

H2H2 N2N2

H3H3 N3N3

H4H4 N4N4

H5H5 N5N5

H6H6 N6N6

H7H7 N7N7

H8H8 N8N8

H9H9 N9N9

H10H10

H11H11

H12H12

H13H13

H14H14

H15H15

H16H16

PANDEMICS

1918 H1N1 SPANISH PANDEMIC

1957 H2N2 ASIAN PANDEMIC

1968 H3N2 HONG KONG PANDEMIC

H5N1 AVIAN INFLUENZA NICD

INFLUENZA PANDEMICS

15101510 1889 – 18901889 – 1890 H2N2H2N2 1899 – 19001899 – 1900 H3N2H3N2 1918 – 19191918 – 1919 H1N1H1N1 “Spanish flu” “Spanish flu” 1957 – 19581957 – 1958 H2N2H2N2 “Asian flu” “Asian flu” 1968 – 19691968 – 1969 H3N2H3N2 “Hong Kong flu” “Hong Kong flu” 2009 - ? H1N1 v “Swine flu”/pandemic 20092009 - ? H1N1 v “Swine flu”/pandemic 2009

NICD

H1N1

1918/19 Pandemic1918

Ag Stasis

(sporadic human cases)

Triple reassortant

Influenza A (H1N1) v

2009 Pandemic

Eurasian

Ag drift

Seasonal flu

Ag drift

Seasonal flu

1957

1977

1998

2009

Positive samples by influenza types and subtypes : Viral Watch South Africa 2009

0

50

100

150

200

250

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51

Week

Nu

mb

er

0

20

40

60

80

Pe

rcen

tag

e

A awaiting typing A H1N1 (seasonal) A H3N2

B Novel H1N1 Detection rate**

Diagnosed and reported H1N1 influenza statistics

Infected individuals

Symptomatically infected

Report to doctor

Doctor takes specimen

Diagnosed and reported H1N1 influenza statistics

Adequate specimen reaches laboratory

Laboratory test reliable

Reported to surveillance authority

PANDEMIC H1N1 DEATHSPANDEMIC H1N1 DEATHS (31(31STST August 2009) August 2009)

TOTAL = 27TOTAL = 27

A) A) PREGNANCYPREGNANCY:: 12 (44%)12 (44%)StageStage:: 11stst trimester trimester 11

33rdrd trimester trimester 1010PuerperiumPuerperium 11

Co-morbidityCo-morbidityNoneNone 5 (42%)5 (42%)Under investigationUnder investigation 11HIVHIV 44TB (only)TB (only) 11Obese + substance abuseObese + substance abuse 11

Age distributionAge distributionRangeRange 16-3716-37

B)B) NON-PREGNANTNON-PREGNANT

Total:Total: 1515

Age range:Age range: 0-53yr0-53yr

a)a) NilNil 33 (20%)(20%)

b)b) Co-morbiditiesCo-morbidities

1.1. HIVHIV 22 (1 TB)(1 TB)

2.2. ObesityObesity 77 (1 asthma, 2 cardiac, 1 (1 asthma, 2 cardiac, 1 diabetes)diabetes)

3.3. DiabetesDiabetes 44 (1 obesity, 1 hypertension)(1 obesity, 1 hypertension)

4.4. TBTB 11

5.5. Premature Premature 11

WHO PANDEMIC WHO PANDEMIC PHASESPHASES

INTERPANDEMIC PERIOD

Phase 1

Phase 2

PANDEMIC ALERT PERIOD

Phase 3

Phase 4

Phase 5

PANDEMIC PERIOD

Phase 6

POSTPANDEMIC PERIOD

CHARACTERISTICS OF PANDEMICS

1. Novel virus

2. Increased transmissibility

3. +/- increased virulence

4. Age shift

5. Relative non-seasonality

6. Geographic heterogeneity

7. Multiple waves

8. Human adaptation seasonal influenza

NICD

3. VIRULENCE

CFR: MEXICO 0.4% (0.3 – 0.6%)

USA 0.2%

SEASONAL 0.04-0.08%

INFLUENZA

1918/1919 5.0%

PANDEMIC

H5N1 60%NICD

INFLUENZA PANDEMICS

1510 1889 – 1890 H2N2 1899 – 1900 H3N2 1918 – 1919 H1N1 “Spanish flu” 1957 – 1958 H2N2 “Asian flu” 1968 – 1969 H3N2 “Hong Kong flu”

1977 H1N1

SEASONAL INFLUENZA 250 – 500,000

DEATHS

> 50 million> 1 million~ 0.5 million

MILD

INFLUENZA PANDEMICS

NO. OF WAVES

1889 – 1890 H2N2

1899 – 1900 H3N2

1918 – 1919 H1N1 2 or 3

1957 – 1958 H2N2 3

1968 – 1969 H3N2 2

NICD

… … a lot of “known knowns; a lot of “known knowns; there are things we know there are things we know we know. We also know we know. We also know

there are known unknowns; there are known unknowns; that is to say we know there that is to say we know there are some things we do not are some things we do not know. But there are also know. But there are also unknown unknowns – the unknown unknowns – the ones we don’t know we ones we don’t know we

don’t know”don’t know”Donald Rumsfeld Donald Rumsfeld

US Secretary of DefenseUS Secretary of Defense

THE IMPONDERABLES - VIRAL

1. ? Further waves

2. ? Replace human seasonal H1N1

3. ? Reassort with human seasonal H1N1

4. ? Mutational resistance development

5. ? Reassort with human seasonal H3N2

6. ? Reassort with avian H5N1

NICD

THE IMPONDERABLES - HUMAN

1. Travel

2. Urbanization

3. Immunosuppression

4. Displaced persons

5. Medical and scientific advances

NICD

THANK YOUTHANK YOUTHANK YOUTHANK YOU

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