- Dr. C.S.N Vittal

witch

The

- Dr. C.S.N Vittal

Replacement of all tOPV with

bOPV (containing types 1 and 3 only)

in routine immunization and

supplemental immunization activities (SIAs)

What is the switch?

DG of WHO -> comprehensive polio eradication strategy

“Polio Eradication and Endgame Strategic Plan”

The first phase of OPV removal

Validate - during the two weeks after the switch

2012

2013-18

2016

2 Wks after…

WHA declared the completion of poliovirus eradication –a “programmatic emergency for global public health”

Removal of all oral polio vaccines (OPVs)- in a phased manner, from both routine programmes and campaigns, to minimize the risk of new polio cases.

A switch from the current trivalent oral polio vaccine (tOPV), containing antigens for poliovirus types 1, 2, and 3, to bivalent OPV (bOPV)

- Complete disposal of tOPV - Collect and review data and validate switch

Brief Introduction ….

2019-2020 : Complete withdrawl of bOPV and OPV routine use

1.Rationale for OPV withdrawal

2.Timelines for switching from tOPV to bOPV

3.Programmatic implications of the switch

The Switch

125 Polio Endemic countries

125 Polio Endemic countries

to 3 endemic countries

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

0

100

200

300

400

Polio

case

s (th

ousa

nds)

Wild Poliovirus Eradication, 1988-2012

19882012

Last type 2 polio in the world

Last Polio Case in India

Data as on 12/02/2014

GLOBAL POLIO CASES

Global Polio Cases :Year 2000 = 719Year 2001 = 483Year 2002 = 1918Year 2003 = 784Year 2004 = 1255Year 2005 = 1979Year 2006 = 1998Year 2007 = 1315Year 2008 = 1651Year 2009 = 1604Year 2010 = 1352Year 2011 = 650Year 2012 = 223Year 2013 = 400Year 2014 = 11

International exportation of poliovirus in 2014

March

March

February

JanuaryAprilJune

AugustSeptember

October

WILD POLIO CASES IN INDIA

Data as on 14.02.2014

Success in India established strategic & scientific feasibility of poliovirus

eradication

Poliovirus Type 2 eradication raised concerns

about continued use of tOPV

Vaccine-derived polio virus (VDPV)

2

VDPV in the immunodeficient

person (iVDPV)

3

VDPV of ambiguous

origin (aVDPV)

1

Circulating VDPV (cVDPV)

– VDPV with evidence of virus circulation in the

population causing two or more

paralytic cases

• cVDPV is associated with sustained person-to-person transmission and is circulating in the environment.

• “Persistent cVDPVs” refer to cVDPVs known to have circulated for more than six months.

• cVDPVs are extremely rare. - During the last ten years, only 24 cVDPV outbreaks have occurred in 21 countries, resulting in more than 750 cases of paralytic polio.

cVDPV

Type 2 (478 cases)

Type 1 (79 cases)

Type 3 (9 cases)

Type 2Type 1

Type 3

>90% VDPV cases are type 2(40% of Vaccine-associated polio is also type 2)

Vaccine-derived polio outbreaks (cVDPVs) 2000-2013

• Why…• What…• How…

Time to answer some queries….

?

The Switch

The objective of the switch is to stop the

emergence of cVDPV2 and VAPP caused by the

attenuated type 2 strain of tOPV.

What is the objective of the switch ?

• The purpose of the switch is to eliminate

persistent cVDPVs associated with the type 2

serotype and to boost protection against wild

poliovirus types 1 and 3

• (the switch will not prevent type 1 or type 3 cVDPV).

Will the switch from tOPV to bOPV eliminate all cVDPV cases

?

1. Until recently, WPVs caused the majority of paralytic polio

cases and attracted the maximum attention. During this time,

tOPV is the best strategy for fighting polio.

2. In recent years, great progress has been made in reducing

polio transmission, especially with the South East Asia region

being certified as polio-free in March 2014.If th

e last wild poliovirus type 2 (WPV2) was reported in

1999, why is type 2 only now being removed from OPV

?

3. Developments in laboratory capacity have allowed for a

better appreciation of the burden caused by cVDPV2s.

4. Only in the last few years have data become available which

show that switching to bOPV could aid eradication of WPVs,

as bOPV provides better immunogenicity than tOPV to

WPV1 and WPV3.

If the last w

ild poliovirus type 2 (WPV2) was reported in

1999, why is type 2 only now being removed from OPV

?

5. Currently, WPV cases reached such low levels that cVDPVs

are causing a relatively high proportion of paralytic polio

cases.

6. Bivalent OPV had to be available to make the switch to bOPV

possible, and bOPV has only become available in the last few

years.

If the last w

ild poliovirus type 2 (WPV2) was reported in

1999, why is type 2 only now being removed from OPV

?

• Increase in the number of individuals susceptible to

poliovirus type 2, which

• In turn will increase the risk of new cVDPV type 2

outbreaks after OPV type 2 cessation…Are there any risks associated with the switch

from tOPV to bOPV

?

How do we address such eventuality?• Wile the objective of the switch is to stop the emergence of cVDPV2 and VAPP caused by the attenuated type 2

strain of tOPV.

• The planned withdrawal of the type 2 component of tOPV is part of the global polio eradication endgame strategy for 2013-2018.

Click to add Title1 All countries are requested to introduce at least one dose of IPV (containing types 1, 2, and 3) into their routine immunization programmes by the end of 2015

1

Click to add Title2 To destroy tOPV stocks immediately after the switch2

Click to add Title1 Selected countries to conduct SIAs with tOPV in the months leading up to switch3

Click to add Title2 Facilitate interruption of transmission with the use of monovalent OPV type 2 in the case of outbreaks

4

Click to add Title1 Hasten eradication by boosting immunity to poliovirus types 1 and 35

How to tackle this risk of possible cVDPV type 2 outbreaks ?

• No. The vaccines can work together to induce a stronger immune response

If both OPV and IPV are given to the same child, is

a vaccine overdose possible?

• To ensure that no country is put at risk of importing a cVDPV2 from another country that continues to use tOPV

Why do all countries need to make the switch from

tOPV to bOPV at the same time?

• IPV does not replicate in the gut, & does not prevent the spread of poliovirus. Using both vaccines together provides the best protection

Why can’t countries move straight to IPV?

?

Importance of IPV introduction

Administration of one dose of IPV would boost humoral and

mucosal immunity in children already immune from OPV,

provide protection against VAPP.

January 2013 : 126 OPV-only using countries

IPV ONLY (47 countries)IPV/OPV (19 countries)OPV ONLY (126 countries)

IPV Introduction status - March 2015

28Date of slide: 3 March 2015

Introduced to date (82 countries or 42%)Formal commitment to introduce in 2015 (106 countries or 55%)

Intend to introduce in 2015 (4 countries or 2%) (Cook Islands, Fiji, Mauritius, Turkmenistan)Intend to introduce in 2016 (Thailand) Formal commitment to introduce in 2016 (Saint Lucia)Not Available

Not applicable

15 introductions 109 commitments/plans to introduce in 2015

Polio Eradication Endgame Plan 2013-18

Introduce• at least one dose of IPV into

routine immunization

Switch• tOPV to bOPV

Withdraw• bOPV & routine OPV use

Before end 2015

2016

2019-2020

Ongoing STRENGTHENING of routine immunization services

Alignment of Containment & OPV Withdrawal Timelines, (2014-2020)

30

2014 2015 2016 2017 2018 2019 2020

WPV + cVDPV1

Phase I: Global readiness coordination

(until end-2015)Phase II:

Global poliovirus type 2 containment period

(2016 – 2018)

Phase III: Long-term poliovirus

containment(as of 2019)

Containment of all Sabin

Global readiness

criteria met

Inventory, destruction, preparation for containment

Certification

2

OPV2 withdrawal

Sabin Destruction, prep.for containment Certification

NOW6 x Regional certification

of WPV eradication

WPV2/cVDPV2 containment

bOPVcessation

Sabin2 containment

Final containment of all WPV/cVDPV

April 2016

Example at country level

SAGE: Strategic Advisory Group of Experts on Immunization

2 weeks Switch Window defined globally

W1 W2 W3 W4

National Switch Date selected by the country: Any day during that

2 week period

Country switches to bOPVRecall & Disposal of tOPV and validation

bOPV distributionstarts 2 weeks

before

Last Switch DateNo more tOPV use

Only bOPV is used globally

Global Validation

The protocol for the Switch was endorsed by SAGE in

October 2014

To Summarize

History of Polio

?????

“…….” Eradication of Polio from the entire world…

…………………….. Who had the world’s last case of

Poliomyelitis … & so on…

History of Polio

In Nea

r Future

Thank Q• Dr. C.S.N.Vittal