1. Polio Eradication and End Game Strategy
IPV Introduction
By M.N Munyoro
NPO/EPI, WHO

2. Key messages in this presentation
Polio Endgame Objectives
Circulating Polio viruses
Components of Endgame Plan
Rationale for OPV withdrawal
WHO SAGE Recommendation for IPV introduction
Planning considerations
Resources

3. Background
Poliovirus eradication is a programmatic emergency for global public health, World Health Assembly, 2012
In response, the Polio Eradication and Endgame Strategic Plan was developed and endorsed by WHA, 2013

4. Circulating polioviruses
Wild
99% reduction in cases of wild poliovirus since 1988
Type 1 (328 cases to date in 2013†)
Type 2 (eliminated worldwide in 1999)
Type 3 (none detected since November 2012)
VAPP**
Vaccine-associated paralytic poliomyelitis (VAPP)**
Estimated ~ globally per year
Type 2 accounts for about 40% of VAPP
OPV related
VDPVs*
Vaccine derived polioviruses (VDPV)
Most are circulating VDPVs (cVDPVs)*
~ per year since 2008
Type 2 cVDPVs account for 97% of cVDPVs
† Per Polio This Week Numbers found at
*Other extremely rare VDPVs include primary immunodeficiency VDPVs (iVDPVs) and ambiguous VDPVs (aVDPVs)
**Refers to spontaneous reversion to neurovirulence of one of the attenuated viruses in OPV. VAPP occurs in OPV recipients or their close contacts in contrast to cVDPVs which are widely transmitted in a community and are not likely to be related to contact with a recent vaccine recipient.
IPV introduction

5. Components of Endgame Plan, 2013-18
Polio detection & interruption
RI Strengthening &
OPV withdrawal
Containment &
Certification
Legacy Planning

6. Major Objectives Virus detection & interruption Introduce IPV
Last wild polio case
Last OPV2 use
Certification
Major
Objectives
Virus detection & interruption
Introduce IPV
Wild virus
interruption
Outbreak response
(esp. cVDPVs)
RI strengthening &
OPV2 'readiness'
OPV 1 & 3
'readiness'
RI strengthening
& OPV withdrawal
Containment & certification
Finalize long-term containment plans
Complete containment
& certification globally
Consultation
Mainstream polio functions, infrastructure & learnings
Legacy Planning

7. Some questions to help understand the rationale for OPV withdrawal
1. WHY do we need to withdraw OPV ?
OPV has the potential to mutate and cause disease and outbreaks – cVPDV
With eradication of wild virus it would no longer be justified to use OPV
2. WHY withdraw OPV2 first (switch tOPV  bOPV)?
Currently, the risks of using OPV2 outweighs its benefits
Wild PV2 has likely been eradicated – last case 1999
Type 2 OPV is leading cause of cVDPV outbreaks
bOPV is available and effective
Prepares for complete OPV withdrawal
Bonus – IPV introduction will help with eradication of wild virus by enhancing immunity to type 1 & 3

8. Some questions to help understand the rationale for OPV withdrawal - continued
3. WHY introduce IPV before switching to bOPV?
Provide immunity PV type 2 – window of risk of exposure to type 2 cVPDV
4. WHY is the timeline for OPV2 withdrawal & IPV introduction condensed?
OPV withdrawal is part of the polio eradication initiative which is operating in urgent timeframe; OPV withdrawal is an integral part of eradication and needs to be coordinated to maximize protection and minimize risk of future cases and outbreaks.
5. WHY not switch all tOPV to IPV all one time ?
OPV continues to be the best vaccine for eradicating wild virus (easy administration, inexpensive, mucosal immunity); similar to above -- phased and coordinated OPV cessation is critical for achieving wild virus eradication and preventing vaccine associated disease and outbreaks.

9. Interrupt transmission if outbreaks occur
Rationale for introducing at least one dose of IPV prior to the trivalentOPV-bivalentOPV switch
Reduce risks
Hasten eradication
Interrupt transmission if outbreaks occur
Reduce risks associated with OPV2 cessation
Lower risk of re-emergence of type 2 polioviruses
Facilitate interruption of transmission with the use of monovalent OPV2 if type 2 outbreaks occur
Boost immunity against types 1 & 3 thus hastening polio eradication
IPV
At least 1 dose of IPV used globally would improve population immunity
Reduces the consequences of type 2 re-emergence by inducing population immunity
Seroconversion* is generally 32-65% for the first dose of IPV
Virtually all who do not seroconvert are still immunologically primed** and may be protected against clinical polio
In the event of a type 2 polio outbreak as a result of reintroduction of the type 2 viruses
a significant proportion of children who have received IPV would already be immune
a dose of mOPV2 in an SIA for outbreak response would lead to higher immunity levels in a population that has received 1 dose of IPV previously than use of mOPV2 in a naïve population because these children will have received 2 doses of a polio containing vaccine instead of just the 1 dose administered in an SIA
IPV boosts systemic immunity (protects against paralytic disease) and intestinal immunity (reduces transmission) in OPV primed populations to all vaccine types contained in prior OPV doses - i.e. it will boost immunity to types 1 and 3, hastening interruption of transmission and providing insurance against reintroduction from other populations.
IPV introduction

10. A hypothetical scenario of estimated VAPP/cVDPV cases
Why withdraw OPV?
As wild polioviruses are eradicated, number of cases related to polio vaccine (VAPP plus cVDPVs) exceeds number of cases related to wild poliovirus (as of 5 Nov. 2013) ?
A hypothetical scenario of estimated VAPP/cVDPV cases
IPV introduction

11. Objective 2 of The Plan Withdrawal OPV in phases
Into routine immunization schedule
Prior to OPV withdrawal
Introduce at least one dose of IPV
Strengthen routine immunization systems
Switch from trivalent OPV (tOPV) to bivalent OPV (bOPV)
Phase 1: remove type 2 component of OPV
Phase 2: withdraw bOPV
IPV introduction

12. DRAFT WHO SAGE Working Group recommendation on IPV schedule
All countries should introduce at least one dose of IPV into their immunization schedules by end of 2015.
IPV is an additional dose to OPV and not a replacement. For example, in an OPV-only using country IPV should be administered in addition to the 3-4 doses of OPV in the primary series.
This dose should be administered during the immunization contact at or after 14 weeks. For example, at the DPT3 or Penta3 visit.

13. IPV introduction – Other considerations
Is country planning to introduce another new vaccine before end of 2015?
Is IPV already licensed by NRAs?
Results of supply system and cold chain assessments
Financing /subsidizing mechanisms- for GAVI & Non GAVI countries
Availability of technical assistance

14. Planned use of IPV: IPV Rationale Summary
IPV induces immunity in a proportion of children which will protect them against polio caused by vaccine viruses (VAPP and cVDPVs) and polio caused by wild poliovirus
IPV should lower risk of re-emergence of type 2 polioviruses
IPV in conjunction with bOPV will decrease the number of cases of VAPP caused by types 1 and 3
IPV will boost immunity to types 1 and 3 which should hasten eradication of types 1 and 3 wild polioviruses and reduce polio disease caused by types 1 and 3 cVDPVs
IPV by inducing immunity to type 2 will facilitate outbreak control with mOPV2 should type 2 viruses be reintroduced
A proportion of the population will already be immune resulting in a higher level of immunity after a dose of mOPV2 in outbreak control than after a dose of mOPV2 to contain an outbreak in a completely susceptible population
The higher the IPV coverage the better, but even low coverage will provide direct benefit to those vaccinated and greatly facilitate building population immunity in an emergency response
This should go up
IPV introduction

15. Features of Inactivated Polio Vaccine (IPV)
Not a live vaccine – no risk of VAPP or VDPVs
Must be administered by injection
Trivalent – produces antibodies to types 1, 2 and 3 poliovirus
A high proportion of vaccinees, generally > 95% of children, have serum neutralizing antibodies after 3 doses to all three polio serotypes
Appears equivalent to OPV in inducing pharyngeal immunity
Inferior to OPV in inducing gut immunity
More costly to produce than OPV
Price now generally in excess of $2.00 per dose but with increased demand, price likely to decrease
Collaborations & investigations underway to explore two “low cost” IPV options:
fractional dose intradermal
adjuvanted intramuscular IPV
GAVI will cover the full cost of purchase for GAVI eligible countries
IPV introduction

16. Resources on live website

17. Thank you For Protecting Me Against Polio