Update on Influenza AH5N1 Activity in Asia

1
Update on Influenza A(H5N1) Activity in Asia

• Nancy J. Cox, Ph.D.
• Chief, Influenza Branch
• National Center for Infectious Diseases
• Centers for Disease Control and Prevention

2
(No Transcript)
3
Pandemic Influenza The Ever Present Threat
4
Virologic and Epidemiologic Criteria for a
Pandemic

• Novel HA subtype, naïve populations
• Causes morbidity and mortality in humans
• Easily transmissible from person to person

5
Direct Interspecies Transmission of Avian Viruses
to Humans Exposed to Infected Poultry

• 1997 18 cases of human respiratory illness
  caused by HP avian H5N1 6 deaths Hong Kong
• 1998/9 8 cases of human respiratory illness
  caused by H9N2 no deaths China, HK
• 2003 2 additional HP H5N1 cases in humans 1
  death China, HK
• 2003 gt80 cases of infection by HP H7N7 avian
  viruses 1death - ND
• 2004 28 cases of human respiratory illness by HP
  H5N1 avian viruses 20 deaths Vietnam and
  Thailand

6
(No Transcript)
7
HEMAGGLUTINATION INHIBITION REACTIONS OF
INFLUENZA H5 VIRUSES
REFERENCE ANTISERA
GOAT
SHEEP
FERRET
FERRET
CHICK
FERRET
FERRET
REFERENCE ANTIGENS
TERN/SA
HK/213
HK/213XPR8
HK/213
GSE/HK
HK/156
RB POC
1.
A/TERN/S. AFRICA/61
1280
80
80
20
640
320
160
2.
A/HONG KONG/213/2003
1280
2560
gt5120
320
1280
320
2560
3.
A/HONG KONG/213/2003 X A/PR/8/34
640
2560
gt5120
320
1280
320
2560
4.
A/GOOSE/HK/437-4/99
320
320
640
80
1280
320
320
5.
A/HONG KONG/156/97
640
320
1280
80
1280
320
320
6.
A/RB POCH/HONG KONG/281/2002
10
640
160
20
160
20
320
160
7.
A/GOOSE/VIETNAM/113/2001
20
80
320
40
80
80
TEST ANTIGENS
8.
A/CHICKEN/KOREA/ES/03
40
320
80
10
80
20
40
9.
A/CHICKEN/VIETNAM/NCVD-7/2003
10
160
40
5
80
5
40
10.
A/CHICKEN/VIETNAM/NCVD-8/2003
20
80
80
20
320
160
160
11.
A/CHICKEN/VIETNAM/NCVD-13/2003
10
40
20
5
160
80
80
12.
A/MUSKOVY DUCK/VIETNAM/NCVD-14/2003
5
80
20
5
80
5
40
13.
A/DUCK/VIETNAM/NCVD-25/2003
5
80
40
10
160
80
80
14.
A/MUSKOVY DUCK/VIETNAM/NCVD-28/2003
5
80
20
5
80
5
40
15.
A/DUCK/VIETNAM/NCVD-29/2003
5
160
40
5
80
5
40
16.
A/CHICKEN/VIETNAM/NCVD-30/2003
10
160
40
5
160
10
40
17.
A/CHICKEN/VIETNAM/NCVD-31/2003
10
160
40
5
80
5
20
18.
A/MUSCOVY DUCK/VIETNAM
10
160
40
5
80
5
80
19.
A/CHICKEN/VIETNAM
10
160
40
5
80
5
40
20
A/VIETNAM/1204/2004
10
160
40
5
80
5
40
21
A/VIETNAM/1194/2004
10
160
40
5
80
5
40
22
A/VIETNAM/1203/2004
10
160
40
5
160
5
80
Serology antigens
8
Evolutionary Relationships Among Influenza A
(H5N1) Hemagglutinin (HA1) Genes in South Asia
1996-2004
Vietnam/1203/2004
Vietnam/1194/2004
Muscovy Duck/NIVR3/2003
limVietnam/3218/2004
Muscovy Duck/Vietnam/NCVD21/2003
Muscovy Duck/Vietnam/4/2004
Muscovy Duck/Vietnam/17/2004
Human H5N1 Isolates
Muscovy Duck/Vietnam/NCVD20/2003
limVietnam/3212/2004
Scale
Thailand/16/2004
Chicken/Vietnam/NCVD11/2003
nucleotides
Duck/Vietnam/NCVD30/2003
Hong Kong/213/2003
stjudePigeon/Hong Kong/WF32/2003
stjudeChicken/Hong Kong/NT47/2003
Rosy-Billed Pochard/Hong Kong/821/2002
stjudeChicken/Hong Kong/YU250/2003
stjudeChicken/Hong Kong/NT71/2003
stjudePheasant/Hong Kong/NT123/2003
Chicken/Korea/ES/2003
stjudeChicken/Hong Kong/YU357/2003
Duck/China/319-2/2003
Chicken/Vietnam/NCVD4/2003
Muscovy Duck/Vietnam/NCVD9/2003
Duck/Vietnam/NCVD25/2003
Teal/Hong Kong/2978/2002
Goose/Vietnam/113/2001
Duck/Meat/Anyang/2001
Goose/Hong Kong/437-4/99
Hong Kong/483/97
Hong Kong/156/97
Goose/Guangdong/96
Goose/Guangdong/96
9
Evolutionary Relationships Among Influenza A(H5)
NA Genes
ckvnncvd-152003
ckvnNCVD-162003
ckvnNIVR-2exe12003
mudkvnncvd-232003
mudkvnNCVD-172003
ckvnncvd-312004
3 additional AA deletion at 37-39
ckvnNCVD-112003
mudkvnncvd-142003
ckvnNCVD-102003
dkvnNCVD-192003
ckvnncvd-302003
dkvnncvd-292003
ckvnNCVD-62003
20 AA deletion (49-68)
mudkvnNIVR-3exe12003
dkvnNCVD-242003
mudkvnNCVD-182003
mudkvnncvd-212003
dkvnNCVD-222003
T83K, S95N, S105G, N270D, Y253H, E382G
ckvnncvd-72003
ckvnnivr-22003
mudkvnncvd-282003
mudkvnnivr-32003
vn11942004
vn12032004
vn12042004
th66352004
rbpoch82102
ckkoes2003
dkmtay2001
gogd196
gogd397
ckhk317501
envhk4371099
envhk437899
dkhkww38100
dkhkww46100
gohkww49100
dkhk2986100
dkhk380501
gs-hk-76.1-2001
gohk3014500
govn11301na
govn32401na
hk21303e2
tealhk2978102
mudkvnNCVD-22003
dkvnncvd-12002
ckvnNCVD-132003
A79T, S189N
ckvnncvd-82003
No AA deletion
mudkvnNCVD-122003
dkvnncvd-252003
ckvnNCVD-32003
ckvnNCVD-42003
ckvnNCVD-52003
mudkvnNCVD-92003
phehknt26100
qulhksf55000
qulhk17213099
hk53297
hk48597
hk48297
hk15697
hk48197
swcot148899
paul73
69
10
Development of Reagents and Methods for
Identification/Detection of H5N1 Viruses

• Develop updated WHO kit for identification of
  H5N1 viruses (antiserum with high antibody titer
  and inactivated antigen for HI tests)
• Develop rapid detection methods for H5 using real
  time PCR (positive RNA controls and primer
  sequences)

11
H5N1 Vaccine Development

• Modified Fodor Vector system
• 8 plasmid approach
• Cloning and characterization
• Selected clones sequence identical to RNA
• Removal of polybasic peptide
• Original QRERRRRKKRGLFG
• Engineered QRETRRGLFG
• Regulatory authority compliance
• No animal derived ingredients

12
Generation of H5N1 vaccine with modified HA using
plasmid-based reverse genetics
N1 NA
PA
PB1
PB2
HA
Mod. H5 HA
NP
NS
M
NA
PR8 h.g. donor
HP avian virus
Bi-directional plasmids expressing both mRNA and
vRNA
Transfect Vero cells
Reassortant Modified H5N1 Vaccine
13
Virus Recovery and Analysis

• Recovery of rg-VN/1203/PR8 reassortant (26)
• Cell culture system
• Certified Vero cells
• Certified cell culture medium
• Amplification in eggs
• Characterization
• Nucleotide sequence analysis HA and NA
• Yield in eggs (goal is approx. 1024 HAU/ml)
• Reference virus must regulatory requirements for
  derivation of reference strain for inactivated
  vaccine production

14
Safety and Immunogenicity

• Chick embryo lethality
• Mice
• LD50 study and/or virus lung titer following IN
  inoculation
• Chickens
• Standard pathotyping (USDA SEPRL)
• Ferrets
• Lung virus titer following IN inoculation (LD50
  study/virulence)
• Immunogenicity
• HI cross test using post infection ferret serum
  (infected with WT rg-VN1203/PR8)
• Protective efficacy in mouse model
• Homologous challenge with wt A/Vietnam/1203/2004
• Heterologous challenge with A/HK/213/2003 or
  other viruses

15
Summary Avian Influenza A(H5N1) as of 2/17/04

• Poultry outbreaks caused by HPAI H5N1 viruses
  reported in Cambodia, China, Hong Kong, Laos
  Indonesia, Japan, S. Korea, Thailand and Vietnam
• Human cases reported by Vietnam (2014 d) and
  Thailand (8 6 d) no human cases reported
  elsewhere - but expected
• Most cases had exposure to sick/dead birds
  family clusters raise questions about
  person-to-person transmission

16
Summary continued

• H5N1 viruses from birds and humans in VN are
  genetically and antigenically closely related
• Human isolates from VN Thailand and 1 group of
  VN avian isolates resistant to adamantanes, but
  sensitive to oseltamivir (Tamiflu)
• Candidate vaccine reference strain produced with
  H5N1 virus from 2003 human case is not an optimal
  antigenic match to 2004 H5N1 viruses might
  provide some protection
• Construction by reverse genetics of new vaccine
  reference strains in 2 U.S. labs and one in U.K.

17
Summary continued

• Need genetic and antigenic comparisons of H5N1
  viruses from more countries for understanding
  H5N1 spread and for developing vaccine strains
• Culling infected birds/proper disposal necessary
  to reduce risk of human infection human exposure
  continues in developing countries with backyard
  flocks constituting majority of poultry (e.g.,
  China has 13 billion birds ¾ of farms have lt 100
  birds)
• Poor or nonexistent human influenza surveillance
  in countries affected by poultry outbreaks

18
Summary continued

• Unprecedented human exposure to H5N1 highly
  pathogenic viruses
• Threat to global health circulation of avian
  H5N1 and human H3N2 viruses in the region, so
  reassortment is possible as is adaptation through
  mutation
• Unlikely H5N1 viruses eradicated soon
  eradication of backyard flocks difficult
  infections in wild birds documented
• International efforts coordinated by WHO/FAO
  assist in culling, surveillance and disease
  control efforts
• As outbreak continues, need to consider H5N1
  vaccine production trigger points target
  populations quantity?

19
Acknowledgements

• Members of the Influenza Branch
• The WHO National Influenza Centers
• The WHO Collaborating Centers in London, Tokyo
  and Melbourne
• The WHO Regional Offices
• WHO Headquarters in Geneva

20
(No Transcript)
21
Likely U.S. Impact of an Influenza Pandemic
Estimates from a CDC Model

• 20-47 million illnesses
• 18-42 million clinic visits
• Up to 730,000 hospitalizations
• 89,000 to 207,000 deaths

22
Seroprevalence of H5 and H9 Antibody in Hong
Kong Poultry Workers, 1997-98
Positive
H5
H9
Group
0
General urban population
5
10
Poultry workers
23
23
Strengthen Global and Domestic Surveillance

• Support, strengthen WHOs Global Influenza
  Network to improve the early warning system
  interactions with NIHE in Hanoi
• Support, strengthen U.S. influenza sentinel
  physician, virologic, and mortality surveillance
  systems
• Develop contingency plans for enhancing
  surveillance when a new subtype is detected
• Develop surveillance methods to monitor
  hospitalized cases of influenza in the U.S. and
  mortality in children