Polio Eradication -- Global Progress and Development of Post-Eradication Strategies: Implications...
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Transcript of Polio Eradication -- Global Progress and Development of Post-Eradication Strategies: Implications...
Polio Eradication -- Global Progress and Development of Post-Eradication Strategies:
Implications for U.S. Stockpile and Outbreak Response
PreparationsNational Vaccine Advisory Committee
February 8-9, 2005
Objectives of Session
• To provide update on polio eradication progress & plans for post-eradication era
• To provide update on U.S. success in eliminating all forms of paralytic polio & status of U.S. polio vaccine stockpile
• To elicit committee discussion re: key actions for U.S. stockpile
(III)Elimination of Paralytic Poliomyelitis in U.S.A.
Epidemiology of Polio – U.S.A. (I)
• Routine childhood immunization program– IPV (1950s) & OPV (1960s)– Elimination of indigenous wild polio (1979) &
imported wild polio (1993)
• Adverse effects of oral polio vaccine– VAPP: average 9 cases / year– Accepted as necessary consequence of OPV
use, to reduce risk of imported wild polio
Paralytic Poliomyelitis and OPV licensing United States, 1960-1969
0
500
1000
1500
2000
2500
3000
1960 1961 1962 1963 1964 1963 1966 1967 1968 1969
0
10
20
30
40
50
60
70
80
90
100non-VAPP VAPP
YEAR
No.
of
Cas
es
tOPV
VA
PP
Cas
es
type 3 mOPV
type 1 mOPV type 2 OPV
Paralytic Poliomyelitis, United States, 1980-1989
0
5
10
15
20
25
30
35
1980 1981 1982 1983 1984 1985 1986 1987 1988 1989
non-VAPP VAPP
YEAR
No.
of
Cas
es
Epidemiology of Polio – U.S.A. (II)
• Cessation of OPV in U.S.– Global polio eradication progress in 1990s:
• Lower risk of imported wild poliovirus in USA• Changing benefit / risk ratio for OPV• VAPP = unacceptable risk
– Transition to IPV:• Sequential IPV-OPV schedule (1997) • All IPV schedule (2000)
– Last VAPP cases occurred in 1999
Paralytic Polio Cases and OPV Doses DistributedUnited States, 1990-2003
0
1
2
3
4
5
6
7
8
9
10
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 20030
5
10
15
20
25
VAPP Cases non-VAPP OPV doses in millions
Year
VA
PP
cas
es
OP
V d
ose
s in
mill
ion
sIPV-OPV
All-IPV
Epidemiology of Polio – U.S.A. (III)
• Post-OPV Cessation Era– High vaccination coverage maintained (2002 NIS)– High seroimmunity to all 3 serotypes after IPV-OPV or
all-OPV schedules (urban areas) (Prevots et al.)
• Paralytic Polio: Current & future risks– Source: Imported wild virus (primary)– Risk groups:
• Under-vaccinated children in urban areas• Vaccine refusers in religious communities
– Magnitude: very low but not zero
Epidemiology of Polio – U.S.A. (Conclusion)
• The U.S. has reached an important milestone – elimination of VAPP, through OPV cessation & transition to IPV.
• A low risk of polio cases or outbreaks in the U.S. remains until the world is polio-free.
• A polio vaccine stockpile, as approved, will help ensure an effective control of future outbreaks.
(IV)U.S. Polio Vaccine Stockpile & Outbreak Response: Status, Issues & Future Directions
Outline
• Topics: – IPV stockpile – OPV stockpile – Global collaboration– State & local
collaboration– Sabin IPV – Antiviral drug
• Order of presentation:– NVAC/ACIP Report– Current Status &
Issues– Future Directions– Points for Discussion
U.S. Polio Vaccine Stockpile: IPV (I)
• NVAC/ACIP report:– Projected / recommended = 8 million doses– Used alone / with OPV for outbreak control– Need for licensed, uncombined IPV
• Current status & issues:– Current = ~4 million doses & holding– Might be difficult to get 8 million doses of
uncombined IPV under current mechanism
U.S. Polio Vaccine Stockpile: IPV (II)
• Future directions– Continue efforts to develop uncombined IPV
stockpile through Pediatric Vaccine Stockpile– Consider other options for IPV stockpile
• Discussion points– How to maintain target supply of uncombined
IPV long-term?– IPV stockpile: U.S. issue only or global one?
U.S. Polio Vaccine Stockpile: OPV (I)• NVAC/ACIP report:
– Access to & effective use of OPV in outbreak– Needed = 8 million doses (tOPV or each mOPV
serotype)– Preferred type = mOPV, if available– Need to develop mechanism for use (IND vs other)
• Current status & issues:– IND for OPV – Need to identify vaccine manufacturer and specific
OPV product to continue
U.S. Polio Vaccine Stockpile: OPV (II)
• Future directions – Discuss regulatory options with FDA – Work with WHO & vaccine manufacturers re: mOPV– Develop IND & explore other emergency response
use mechanisms
• Discussion points– Proceed to mOPV stockpile without tOPV?– Are there other emergency response mechanisms to
use?
U.S. Polio Vaccine Stockpile: Global Collaboration (I)
• NVAC/ACIP report:– CDC, FDA, WHO & other int’l partners– Finance, create & maintain global PVS– Guaranteed & immediate U.S. access
• Current status & issues:– CDC & WHO staff – ongoing collaboration on
stockpile & outbreak response– CDC will collaborate with FDA & other agencies –
regulatory issues & mechanisms for use of vaccines
U.S. Polio Vaccine Stockpile: Global Collaboration (II)
• Future directions– Support WHO efforts to…
• License mOPV & develop mOPV stockpile• Evaluate the safety of Sabin IPV (sIPV)• Assess potential use of antiviral drug• Determine appropriate global stockpile size,
composition & regulation
• Discussion points (sIPV & antiviral drug)
U.S. Polio Vaccine Stockpile: State & Local Collaboration
• NVAC/ACIP report:– Develop polio outbreak response plans
• Current status & issues:– Outbreak response plan being drafted
• Future directions / discussion– Involve CSTE, NACCHO & others in outbreak response plan
development
U.S. Polio Vaccine Stockpile: Sabin IPV
• Global developments– Well outlined in Dr. Cochi’s presentation
• Discussion points– Efficacy? Safety? Source?– Issues for potential licensure of sIPV in US for
stockpile use?– Emergency use only (IND and/or other)?
U.S. Polio Vaccine Stockpile: Antiviral Drug
• Developments & issues– Outlined in Dr. Cochi’s talk– WHO-CDC-Private collaborative group– Exploring potential candidate antiviral drugs– Wider consideration: proposed NAS meeting
• Discussion points– Support for NAS-sponsored meeting?– Potential to add as component of stockpile?
U.S. Polio Vaccine Stockpile: Conclusions
• U.S. stockpile: not yet a reality -- optimal size, composition & use
• IPV stockpile: affected by economic issues• OPV stockpile: direction pending
– Global developments re: mOPV– Regulatory issues / emergency use options
• Potential products: evaluation / development– Sabin IPV, Antiviral Drug
Acknowledgements
• WHO– David Heymann– Bruce Aylward– Roland Sutter– Anna-Lea Jenny
• Harvard SPH & other– Kim Thompson– Rad Tebbens– Marc Collett
• CDC– Hamid Jafari– Denise Johnson– Linda Venczel– Margie Watkins– Nalinee Sangrujee– Mark Pallansch– Jane Seward– Lorraine Alexander– Kristin Kenyan
Thanks!
U.S. Polio Vaccine Stockpile: Discussion (I)
• IPV Stockpile:– How to maintain target supply of uncombined
long-term?– IPV stockpile: U.S. issue only or global one?
• OPV stockpile:– Proceed to mOPV stockpile without tOPV?
U.S. Polio Vaccine Stockpile: Discussion (II)
• Sabin IPV:– Efficacy? Safety? Source?– Issues for potential licensure of sIPV in US for
stockpile use?– Emergency use only (IND or other)?
• Antiviral drug:– Support for NAS-sponsored meeting?– Potential to add as component of stockpile?
Extra slides
Paralytic Poliomyelitis United States, 1951-1959
0
5000
10000
15000
20000
25000
1951 1952 '53 1954 '55 1956 '57 1958 '59
IPV licensed
YEAR
Pol
iom
yelit
is C
ases
*
Paralytic Poliomyelitis United States, 1970-1979
0
5
10
15
20
25
30
35
1970 1971 1972 1973 1974 1975 1976 1977 1978 1979
non-VAPP VAPP
YEAR
No.
of
Cas
es