3. WHO PANDEMIC PHASES INTERPANDEMIC PERIOD Phase 1 Phase 2
PANDEMIC ALERT PERIOD
Phase 3
Phase 4
Phase 5
PANDEMIC PERIOD
Phase 6
POSTPANDEMIC PERIOD

4. INFLUENZA VIRUS

5. MILESTONES IN INFLUENZA
1933 Demonstration of virus transmission to ferrets Smith et al
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
1945 Licence of first influenza vaccine in USA

6. I cannot forecast to you the action of Russia
I cannot forecast to you the action of Russia. It is a riddle wrapped in a mystery inside an enigma.
Sir Winston Churchill
Radio 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 Schoub
NICD, June 22, 2009

7. SPORADIC INFLUENZA
PANDEMIC INFLUENZA
SEASONAL INFLUENZA

8. NICD

9. SPORADIC INFLUENZA
PANDEMIC INFLUENZA
SEASONAL INFLUENZA

11. 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)
2002
H7N2 1
United States (Virginia)
2003
2 (1 death)
H7N7
89 (1 death)
The Netherlands
New York
1 (child)
2003- (ongoing)
262/440 (60%)
Vietnam, Thailand, Cambodia, Indonesia, China, Turkey, Iraq, Azerbaijan, Egypt etc
2004
H7N3 2
Canada (British Columbia)
H10N7
2 (infants)
Egypt
NICD

12. SPORADIC INFLUENZA
PANDEMIC INFLUENZA
SEASONAL INFLUENZA

16. 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”
NICD

17. SPORADIC INFLUENZA
PANDEMIC INFLUENZA
SEASONAL INFLUENZA

18. 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”
H1N1
NICD

19. RECOMMENDED VACCINE FORMULATION
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/ 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

20. ONSET & DURATION OF INFLUENZA SEASON: 1985 - 2007
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
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
Mean onset
2007
Apr
May
Jun
Jul
Aug
Sep
Median onset:
Week 23
Range 15-28
Median peak:
Week 27
Range 20-32
Median duration:
10 weeks
Range 7-17

21. INFLUENZA VIRUS

22. (9 subtypes)
(16 subtypes)
NICD

23. HAEMAGGLUTININS H1 N1 NEURAMINIDASES H2 N2 H3 N3 H4 N4 H5 N5 H6 N6
PANDEMICS
1918 H1N1 SPANISH PANDEMIC
1957 H2N2 ASIAN PANDEMIC
1968 H3N2 HONG KONG PANDEMIC
H5N1 AVIAN INFLUENZA
NICD

24. 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”
? H1N1 v “Swine flu”/pandemic 2009
NICD

25. H1N1
Ag Stasis
(sporadic
human cases)
Ag drift
Seasonal flu
1957
1977
1998
2009
1918
1918/19 Pandemic
Triple reassortant
Influenza A (H1N1) v
2009 Pandemic
Eurasian

28. Positive samples by influenza types and subtypes :
Viral Watch South Africa 2009 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
Number 20 40 60 80
Percentage
A awaiting typing
A H1N1 (seasonal)
A H3N2 B
Novel H1N1
Detection rate**

29. Diagnosed and reported H1N1 influenza statistics

30. Diagnosed and reported H1N1 influenza statistics
Reported to surveillance authority
Laboratory test reliable
Adequate specimen reaches laboratory
Doctor takes specimen
Report to doctor
Symptomatically infected
Infected individuals

31. PANDEMIC H1N1 DEATHS (31ST August 2009)
TOTAL = 27
A) PREGNANCY: 12 (44%)
Stage: 1st trimester 1
3rd trimester 10
Puerperium 1
Co-morbidity
None (42%)
Under investigation 1
HIV 4
TB (only) 1
Obese + substance abuse 1
Age distribution
Range

32. B) NON-PREGNANT
Total: 15
Age range: 0-53yr
Nil (20%)
b) Co-morbidities
HIV (1 TB)
Obesity (1 asthma, 2 cardiac, 1 diabetes)
Diabetes (1 obesity, 1 hypertension) TB
Premature

33. WHO PANDEMIC PHASES INTERPANDEMIC PERIOD Phase 1 Phase 2
PANDEMIC ALERT PERIOD
Phase 3
Phase 4
Phase 5
PANDEMIC PERIOD
Phase 6
POSTPANDEMIC PERIOD

34. CHARACTERISTICS OF PANDEMICS
Novel virus
Increased transmissibility
+/- increased virulence
Age shift
Relative non-seasonality
Geographic heterogeneity
Multiple waves
Human adaptation  seasonal influenza
NICD

35. 3. VIRULENCE CFR: MEXICO 0.4% (0.3 – 0.6%) USA 0.2%
SEASONAL %
INFLUENZA
1918/ %
PANDEMIC
H5N %
NICD

37. INFLUENZA PANDEMICS 1977 H1N1 1510 1889 – 1890 H2N2 1899 – 1900 H3N2
1918 – 1919 H1N1 “Spanish flu”
1957 – 1958 H2N2 “Asian flu”
1968 – 1969 H3N2 “Hong Kong flu”
DEATHS
> 50 million
> 1 million
~ 0.5 million
MILD
1977 H1N1
SEASONAL INFLUENZA – 500,000

39. NICD

41. INFLUENZA PANDEMICS NO. OF WAVES 1889 – 1890 H2N2 1899 – 1900 H3N2
1918 – H1N or 3
1957 – H2N
1968 – H3N
NICD

42. Donald Rumsfeld US Secretary of Defense
… a lot of “known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – the ones we don’t know we don’t know”
Donald Rumsfeld
US Secretary of Defense

43. THE IMPONDERABLES - VIRAL
? Further waves
? Replace human seasonal H1N1
? Reassort with human seasonal H1N1
? Mutational resistance development
? Reassort with human seasonal H3N2
? Reassort with avian H5N1
NICD

44. THE IMPONDERABLES - HUMAN
Travel
Urbanization
Immunosuppression
Displaced persons
Medical and scientific advances
NICD

45. THANK YOU