1. Situation report Europe and forward look to the autumn
The A(H1N1v) pandemic
Situation report Europe
and forward look to the autumn
Zsuzsanna Jakab, Director European Centre for Disease Prevention and Control
Swedish Presidency Workshop, Jönköping, 2-3 July 2009

2. Pandemics of influenza
Recorded human pandemic influenza (early sub-types inferred)
H2N2
H2N2
H1N1
H1N1
H1N1v
H3N8
H3N2
1915
1925
1955
1965
1975
1985
1995
2005
1895
1905
2010
2015
What are pandemics? Pandemics are when a new influenza A emerges to which most or many of the population have no immunity. The result usually from an animal influenza combining some of its genes with a human influenza. To be a pandemic strain an influenza A virus needs to have three or four characteristics. They need to be able to infect humans, to cause disease in humans and to spread from human to human quite easily. An additional criteria that is often applied is that many or most of the population should be non-immune to the new virus.
Note this animated slide was first developed by the National Institute of Infectious Disease in Japan and we are grateful to them and especially Masato Tashiro for letting us use it.
1889
Russian
influenza
H2N2
1900
Old Hong Kong influenza
H3N8
1918
Spanish
influenza
H1N1
1957
Asian
influenza
H2N2
1968
Hong Kong
influenza
H3N2
2009
Novel
influenza
H1N1v H7 H5
H9*
1980
1997
Recorded new avian influenzas
1996
2002
1999
2003
1955
1965
1975
1985
1995
2005
Reproduced and adapted (2009) with permission of Dr Masato Tashiro, Director, Center for Influenza Virus Research, National Institute of Infectious Diseases (NIID), Japan.
Animated slide: Press space bar

3. Situation report Europe, as of 1 July 2009

4. Cumulative distribution of confirmed cases of A(H1N1)v by day of reporting, as of 29 June 2009, log scale
Selected European countries
10 000 UK
1 000
Spain
Spain was leading the way but it was now overtaken by UK : Germany and France are coming up.
This will happen to all EU countries in the Autumn.
Germany
France
Number of cases, logarithmic scale
100 10 1
26/04/09
03/05/09
10/05/09
17/05/09
24/05/09
31/05/09
07/06/09
14/06/09
21/06/09
28/06/09
Animated slide: Press space bar

5. The situation could be a lot worse for Europe
The situation could be a lot worse for Europe! (Situation circa summer 2009)
A pandemic emerging in SE Asia
A pandemic strain emerging in the Americas
Immediate virus sharing so rapid diagnostic and vaccines
Based on A(H1N1)v currently not that pathogenic
Some seeming residual immunity in a major large risk group
No known pathogenicity markers
Initially susceptible to oseltamivir
Good data and information coming out of North America
Arriving in Europe in the summer
Milder presentation initially
Delayed virus sharing
Based on a more pathogenic strain, e.g. A(H5N1)
No residual immunity
Heightened pathogenicity
Pandemics come in all shapes and sizes and are highly unpredictable. This slide should be looked at with a later one – on Known Knowns and Known Unknowns – this slide in particular shows how fortunate we have been so far with this pandemic
Inbuilt antiviral resistance
Minimal data until transmission reached Europe
Arriving in the late autumn or winter
Severe presentation immediately
Contrast with what might have happened — and might still happen!

6. But no room for complacency (Situation and information: late May 2009)
Pandemics take some time to get going (1918 and 1968).
Some pandemic viruses have ‘turned nasty’ (1918 and 1968).
Is the ‘mildness’ and the lack of older patients because older people are resistant or because the virus is not transmitting much among them?
There will be victims and deaths — as in the US — in risk groups (young children, pregnant women and especially people with other underlying illnesses).
As the virus spreads south, will it exchange genes with seasonal viruses that are resistant: A(H1N1)-H247Y, more pathogenic A(H3N2), or even highly pathogenic A(H5N1)?
An inappropriate and excessive response to the pandemic could be worse than the pandemic itself.
This slide speaks for itself. The last line refers to some reserve plans which countries have which if enacted would be an over-response.

7. So far in Europe A mild disease in most people
Easy to miss in surveillance
Some severely ill and starting to see deaths – mostly in people with other underlying conditions
Few cases in people over 60 years
Spreading efficiently
Out-breaks in schools (or easier to see in schools?)

8. Initial experience in North America 2009 – the default position

9. Emerging themes in North America, early June 2009 (1)
Early epidemic about 1 million infected ( = 0.3% of population) – compared to minimum 25% expected attack rate
Infection rate for probable and confirmed cases highest in 5−24 year age group.
Hospitalisation rate highest in 0−4 year age group, followed by 5−24 year age group.
Pregnant women, some of whom have delivered prematurely, have received particular attention but data inadequate to determine if they are at greater risk from H1N1v than from seasonal influenza as already established.
Most deaths in 25−64 year age group; most with known risks for severe disease.
Morbid obesity a risk but may be indicator for pulmonary risk.
Adults, especially 60 years and old, may have some degree of preexisting cross-reactive antibody to the novel H1N1 flu virus.
Transmission persisting in several regions of the U.S.
Expected to run on throughout the summer and then accelerate.
This and the next slide represents where the US experience is as of late May. However, this picture will change and its important to monitor the CDC web-site at    and the US (Human Health Services) pandemic website at The regular outputs are published on a Friday specifically at

10. Emerging themes in North America, end June 2009 (2)
Containment impossible with multiple introductions and R0 1.4 to 1.6.
Focus on counting laboratory-confirmed cases changing to seasonal surveillance methods.
Outpatient influenza-like illness, virological surveillance (including susceptibility), pneumonia and influenza mortality, pediatric mortality and geographic spread.
Serological experiments and epidemiology suggest 2008–2009 seasonal A(H1N1) vaccine does not provide protection.
Preparing for the autumn and winter when virus is expected to return.
Communication difficulty — a pandemic may be 'mild' yet cause deaths
25% of U.S. stockpile deployed to states (includes medication and equipment)
determining who to give vaccine, if and when to begin using vaccine
school closures being analysed to determine effectiveness
This and the last slide represents where the US experience is as of late May. However, this picture will change and its important to monitor the CDC web-site at   and the US (Human Health Services) pandemic website at The regular outputs are published on a Friday specifically at

11. Forward look for Europe

12. Idealised curve for planning Reality is never so smooth and simple
Initiation Acceleration Peak Declining
25%
aths
20%
15%
Proportion of total cases, consultations, hospitalisations or de
For planning purposes there are these four components of a pandemic wave – Initiation, Acceleration, Peak and Decline. After the decline there may be a second and even third wave before influenza settles back down to its seasonal pattern again. Even then the seasonal flu is usually worse than the years before the pandemic because the seasonal flu is invigorated with new genetic material. The same four phases actually apply to epidemics as well. However, no pandemic has ever behaved in quite so neat a way. Pandemics don’t follow set patterns and each is different.
10% 5% 0% 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Week
Single wave profile showing proportion of new clinical cases, consultations, hospitalisations or deaths by week. Based on London, 2nd wave 1918.
Source: Department of Health, UK
Animated slide: Please wait

13. One possible European scenario — summer and autumn 2009
Initiation Acceleration Peak Declining
25%
20%
15%
Proportion of total cases, consultations, hospitalisations or deaths
Presently (May-June 2009) Europe seems to be in a prolonged initiation phase with occasional outbreaks and small peaks. This could go on for months with the real first wave coming in the autumn or winter. But there are other scenarios
10% 5% 0%
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
Month
In reality, the initiation phase can be prolonged, especially in the summer months. What cannot be determined is when acceleration takes place.
Animated slide: Press space bar

14. One possible European scenario — summer 2009
October
July
September
Outbreaks will occur at different dates in different countries – exactly when acceleration will take place unclear. The UK suggests we cannot assume it will be October or November – Dr Helen Shirley-Quirk will tell us more later.
August
August
Animated slide: Press space bar

15. Some of the 'known unknowns' in the 20th century pandemics
Three pandemics (1918, 1957, 1968)
Each quite different in shape and waves
Some differences in effective reproductive number
Different groups affected
Different levels of severity including case fatality ratio
Imply different approaches to mitigation
The three pandemics of the 20th century show how these known unknowns can result in important changes. More detail on the different pandemics are available at

16. 1918/1919 pandemic: A(H1N1) influenza deaths, England and Wales
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000 27 29 31 33 35 37 39 41 43 45 47 49 51 2 4 6 8 10 12 14 16 18
1918
1919
Week no. and year
Deaths in England and Wales
Lets look at previous pandemics. This one is the worrying one Its important to emphasise that this and the other slides of 1957 and 1968 are from one country – the UK and ECDC is grateful to the Department of Health in London and UK’s Health Protection Agency for making the public data available to ECDC. There are data from other countries but the important point is that the pandemics varied a lot. They also varied in detail between European countries and even within countries.
The 1918/1919 pandemic is the worst ever seen. It is concerning for 2009 with the small herald wave in the late Spring and then the massive autumn wave. It has been estimated that if it happened again it would result in perhaps about a million additional deaths in the European Union area see next slide and Murray CJL Lopez AD, Chin B, Feehan D, Hill KH Estimation of potential global pandemic influenza mortality on the basis of vital registry data from the pandemic: a quantitative analysis, Lancet (2006); 368:
1918/19: ‘Influenza deaths’, England and Wales. The pandemic affected young adults, the very young and older age groups.
Transmissibility: estimated Basic Reproductive Number (Ro)
Ro = 2-3 (US) Mills, Robins, Lipsitch (Nature 2004)
Ro = (UK) Gani et al (EID 2005)
Ro = (UK) Hall et al (Epidemiol. Infect. 2006)
Ro = (Geneva) Chowell et al (Vaccine 2006)
Courtesy of the Health Protection Agency, UK

17. 1957/1958 pandemic: A(H2N2) — especially transmitted among children
1,000
800
600
influenza
Recorded deaths in England and Wales from
400
The 1957 pandemic was in some ways the nearest to the idealised planning wave. There was a single sharp wave in the late autumn in the UK. Transmission was also especially among children and there are many historical media reports of schools having to close because of sickness in children and teachers.
200 6 13 20 27 3 10 17 24 31 7 14 21 28 5 12 19 26 2 9 16 23 30 7 14 21 28 4 11 18 25 1 8 15 22
July
August
September
October
November
December
January
February
Week number and month during the winter of 1957/58
1957/58: ‘Influenza deaths’, England and Wales
Transmissibility: estimated Basic Reproductive Number (Ro)
Ro = 1.8 (UK) Vynnycky, Edmunds (Epidemiol. Infect.2007)
Ro = 1.65 (UK) Gani et al (EID 2005)
Ro = 1.5 (UK) Hall et al (Epidemiol. Infect. 2006)
Ro = 1.68 Longini et al (Am J Epidem 2004)
Courtesy of the Health Protection Agency, UK

18. So what can we expect in our countries?
Some features from the ECDC risk assessment

19. Proportion of total cases, consultations, hospitalisations or de
It will vary from place to place – and local can be more intense than national
25%
aths
20%
15%
Proportion of total cases, consultations, hospitalisations or de
Also there is a lot of local variation. This is an idealised smooth national curve with idealised local curves showing how the national curve can hides a series of short, sharp local epidemics. These can have higher peaks and this is why planning guidance for local areas often has higher planning assumptions (e.g. numbers of patients a hospital can expect to have to deal with) that is higher than what you might expect from national idealised curves.
10% 5% 0% 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Week
In reality, larger countries can experience a series of shorter but steeper local epidemics.
Animated slide: Press space bar

20. clinical attack rate (%)
Numbers affected in seasonal influenza epidemics and pandemics (overall clinical attack rate in previous pandemics)
45%
40%
35%
30%
25%
clinical attack rate (%)
This and the next slide shows how generally you get many more people being infected, getting sick and needing hospital care in a pandemic compared to what happens each year with seasonal influenza with only 5% to 10% attack rate each year.
20%
15%
10% 5% 0%
Seasonal influenza
1918 New
1918
1918
1957 SE
1968
York State
Leicester
Warrington
London
Kansas City
and Wigan

21. Seasonal influenza compared to pandemic — proportions of types of cases
There will be pressure on the primary and secondary health services – especially paediatric and intensive care.
Deaths
Requiring hospitalisation
Clinical symptoms
But remember this is idealised – and in 2009 in North America this is not putting as many people into Hospital as you would expect from the above
Deaths
Requiring hospitalisation
Asymptomatic
Clinical symptoms
Asymptomatic
Seasonal influenza
Pandemic

22. Good news Older people spared Sensitive to antivirals
No pathogenicity markers
But influenza is promiscuous – will it pick up any ‘bad’ genes on its winter holiday in the south – primary oseltamivir resistance from seasonal flu or even pathogenicity genes from ‘bird flu’ A(H5N1).

23. Measuring the severity of a pandemic

24. There is an expectation that pandemics should be graded by severity
But there are difficulties:
Severity varies from country to country.
It can change over time.
Some relevant information is not available initially.
Key health information includes medical and scientific information:
epidemiological, clinical and virological characteristics
There are also social and societal aspects:
vulnerability of populations;
capacity for response;
available health care;
communication; and
the level of advance planning.
The best discussion on this area is at and

25. WHO: A(H1N1)v — a ‘moderate’ pandemic

26. What is meant by 'moderate' and 'severe'? Not a simple scale
What most people experience. Attributable risks? For most people it’s a mild self-limiting disease.
Death ratio. Expectation of an infected person dying (the Case Fatality Ratio): < 0.5% of reported cases.
Hospitalisation rate: Rates for children aged 0-23 months, 2-4 years, and 5-17 years were 1.1, 0.3, and 0.3 per 10,000, respectively. Rates for adults aged years, years, and >= 65 years were 0.1, 0.1, and 0.2 per 10,000, respectively.1
Pathogenicity markers and animal studies. No markers but ferret data indicate somewhat more severe than seasonal flu.
Number of people falling ill with respiratory illnesses at one time — 'winter pressures'. Pressure on the health services' ability to deal with these — very related to preparedness and robustness. Watch UK, Australia, Argentina, Chile, New Zealand.
Critical service functioning. Peak prevalence of people off ill or caring for others. Watch Australia, Chile, New Zealand.
Source: and
Influenza Season Week 24 ending June 20, 2009

27. What is meant by 'moderate' and 'severe'? Not a simple scale
Certain groups spared: older people.
Certain individual dying unexpectedly, e.g. children, pregnant women, young healthy adults.
Public and media perception: low perception of risk at present
Conclusion
Not easy to come up with a single measure of severity.
May be better to state or agree what interventions/countermeasures are useful and justifiable (and what are not).
Source: and
and

28. Surveillance in a pandemic – future look
This will be crucial to detect
Changes in the behaviour of the virus
Discover who is really at risk
Will have to stop asking for numbers very soon
Reliance on sentinel work – the previous EISS system through TESSy
Reporting of severe disease especially important for informing the antiviral and vaccine priorities
Special workshop July in Stockholm

29. Conclusions
This pandemic will run through the rest of
The first wave will probably start earlier than we might like.
While this looks like a ‘moderate’ pandemic - there will be surprises.
Europe is better prepared than many other regions and a lot better prepared than we were in 2005.
Final preparations will be very worthwhile.
ECDC will be there to work with the Commission, EMEA and WHO to give every support to Member States.

30. Thank you!