-Dr. Ruchita Banseria

POLIO ENDGAME STRATEGY

& IPV

INTRODUCTION

Introduction • In pre-vaccination era poliomyelitis was found in all

countries of the world.• The extensive use of polio vaccines since 1954

eliminated disease in developed countries.• In 1988 the world health assembly resolved to eradicate

poliomyelitis globally, reduced the number of polio endemic countries from more than 125 to 3 in 2014.

• Four out of six region of WHO have been certified polio-free: The Americas (1994), Western Pacific (2000), Europe (2002) and SEAR (2014).

• 80% of world’s population now lives in polio-free areas.

Global Polio Eradication Initiative (GPEI)

• The Global Polio Eradication Initiative (GPEI), launched in 1988 at the 41st World Health Assembly.

• GPEI spearheaded by WHO in partnership with UNICEF, CDC & Rotary International largest public-private partnership for public health.

• GPEI designed a strategy for India called National Polio Surveillance Project (NPSP), a joint project of the WHO and GOI.

• It aims to interrupt transmission of wild poliovirus as quickly as possible, achieve certification of global polio eradication, contribute to health systems development, and strengthen routine immunization and surveillance for other communicable diseases.

• GPEI has developed evidence based strategies and implemented timely interventions which resulted in significant reduction in the number of polio-endemic countries from more than 125 in 1988 to 3 in 2015.

• The strategy to eradicate polio is based on preventing infection by immunizing every child until transmission is blocked and the virus dies out.

• During designated national immunization days (NIDs), which are usually conducted over three to four days, polio vaccination teams consisting of trained community volunteers walk from house to house to identify and vaccinate every child under 5 years of age with oral polio vaccine.

Global scenario• Since the launch of GPEI in 1988 , the global incidence

of polio cases has decreased by over 99% from an estimated 350,000 cases to 26 reported cases in 2015.

• In 2015, only 3 countries (Afghanistan , Nigeria and Pakistan)

• Failure to eradicate polio from these 3 countries could result in as many as 200,000 new cases every year within 10 yrs, all over the world.

Indian scenario• In India, Vaccination against polio started in 1978 with

extended programme on immunization.• Pulse Polio Immunization launched in 1995.• In 2009, India had half the number of polio cases in the

world.• By 2011, in less than two years’ time, India brought polio

infections to the zero level.• India’s last reported polio case was a 2-year-old girl in the

Howrah district of West Bengal, on 13 January 2011.• India removed from list of polio-endemic countries in 2012.• South East Asia region was declared polio free on March

27th 2014.

Epidemiology of Poliomyelitis

• It is viral infection caused by poliomyelitis virus, an enterovirus belonging to the Picornavirdae virus family.

• Has three serotypes ( type 1 , type2 , and type 3)

• Most of the children show minor symptoms but as many as 1 in 200 children will be paralysed.

Agent

• The incubation period for paralytic poliomyelitis is commonly 7-14 days (range 3-35 days).

• Type 2 wild poliovirus has been eliminated in the world – the last wild type 2 polio virus was detected in India in 1999.

• Type 1 is the most pervasive strain of polio virus and type 3 is at very low levels.

• The incubation period for paralytic poliomyelitis is commonly 7-14 days (range 3-35 days)

• RESERVOIR OF INFECTION : Man. For every clinical cases, there may be 1000 subclinical cases in children and 75 in adults .No chronic carriers.

• INFECTIOUS MATERIAL : Faeces and oropharyngeal secretions

Host

• AGE : children more susceptible than adults. The most vulnerable age 6 M to 3 Yrs.

• Sex: Males infected 3 times than females.

• RISK FACTORS : fatigue, trauma, intramuscular injections, operative procedures & administration of immunizing agents Ex. alum containing DPT

• IMMUNITY :Infection from one serotype does not protect completely against other serotypes. Type 2 virus-most effective antigen.

Environment

• Polio is more likely to occur during the rainy season.

• Approximately 60 % cases recorded in India were during June to September.

• Overcrowding, poor sanitation, distant geographic locations, areas with high birth rates , conflict areas.

Modes of transmission

• (a) FAECAL-ORAL ROUTE

• (b) DROPLET INFECTION

Clinical spectrum of polio

• Inapparent (subclinical) infection: no signs and symptoms, 91-96% of infection

• Abortive polio or minor illness : mild and self limiting illness due to viraemia 4-8% of infection

• Non-paralytic polio: presenting features are stiffness and pain in neck and back. Disease last for 2-10 days occurs in approx. 1 %

• Paralytic polio: <1 % occurrence . Invades CNS and varying degree of paralysis.

Types of Polio vaccine1) OPV :

• 1961 by Albert Sabin, Live attenuated vaccine.

• Provide both humoral and Mucosal intestinal (Gut) immunity .

• Mucosal intestinal immunity prevent infection with wild polio virus.

• Intestinal immunity is the main reason why mass campaigns with OPV can rapidly stop person to person transmission of wild polio virus.

Risks associated with use of OPV

Vaccine associated paralytic polio (VAPP )

• VAPP is caused by a strain of poliovirus that has genetically changed in the intestine from the original attenuated vaccine strain contained in OPV.

• It is associated with a single dose of OPV administered in a child or can occur in a close unvaccinated or non –immune contact of the vaccine recipient who is excreting the mutated virus.

• The risk of VAPP varies by dose and by setting.• There are no outbreaks associated with VAPP. • Estimated 250-500 VAPP cases occur globally every year (25-

30 cases per year in India)

Vaccine derived poliovirus (VDPV) :

A VDPV is a very rare strain of poliovirus, genetically changed from the original strain contained in OPV. Mostly by type 3 strain followed by type 2 and 1

Types of VDPV :

1) cVDPV (Circulating vaccine derived polio virus ) : A cVDPV is associated with sustained person to person transmission and is circulating in the community under conditions of low population immunity.

2) iVDPV (Immununo deficiency –related vaccine –derived polio virus) reported in immunodeficient patients who have prolonged infections after exposure to OPV.

3) aVDPV (ambiguous vaccine derived polio virus) currently have unclassified source (i.e., a single isolate from a healthy or non-immunodeficient person; environmental isolates without an associated AFP case).

Among these 3 types, cVDPV causes sustained circulation. Due to the risks of this OPV must be phased out to secure a lasting polio-free world.

2) IPV :

• Developed in 1955 by Dr Jonas Salk.• Consists of inactivated polio strains of all three

types.• Excellent humoral immunity no gut immunity.• In some Indian studies shows that IPV given to

OPV Primed children boosts the mucosal intestinal immunity.

• No risk of VAPP or VDPV.

Polio Eradication & Endgame Strategic Plan 2013-2018

• On 26 May 2012, the World Health Assembly declared the completion of poliovirus eradication to be a “programmatic emergency for global public health” and called for the development of comprehensive polio endgame strategy.

• In response to this directive, the GPEI developed Polio Eradication & Endgame Strategic Plan (PEESP) 2013-2018.

Objectives • The four main objectives of the Plan :

1) Poliovirus detection and interruption: Stop all WPV transmission by the end of 2014 and new cVDPV outbreaks within 120 days of confirmation of the first case

2) Immunization systems strengthening and OPV withdrawal: Hasten the

interruption of all poliovirus transmission and help strengthen immunization systems

3) Containment and certification : this objective encompasses the certification of the eradication and containment of all wild poliovirus in all WHO regions by end of 2018.

4) Legacy planning: Ensure that a polio-free world is permanent and that the investment in polio eradication provides public health dividends for years to come

Polio Endgame Strategy

• Step 1 :Introduction of IPV into routine immunization by October 2015 :

by end of 2015, introduce at least 1 dose of IPV in RI at least 6 months before the switch from tOPV to bOPV (1 and 3 strain)

• Step 2: tOPV-bOPV switch by April 2016 : from 2016, switch from tOPV to bOPV (does not contain type 2

Sabin virus) in RI and polio campaigns.

• Step 3: withdrawal of routine OPV use : plan for the eventual withdrawal of all OPV in routine use by

2019-2020.

Three distinct steps of polio endgame strategy

Introduce atleast one dose of IPV in RI

Switch tOPV to bOPV

Withdraw bOPV & routine OPV use

Before end 2015

2016

2019-2020

On going strengthening of routine immunization

Rationale for the introduction of IPV into RI

• The primary purpose of introducing IPV into RI is to boost population immunity against type2 poliovirus during and after the planned global withdrawal of OPV2 and switch from tOPV to bOPV.

• To boost both humoral and mucosal immunity against poliovirus types 1 and 3, which may also hasten the eradication of these WPVs.

• To reduce VAPP risks.

Global switch

Withdrawal of type 2 component of tOPV : Switch from tOPV – bOPV

• Primary objecties of switch are:- Successfully recall tOPV and introduce bOPV in

April 2016- Minimize tOPV wastage after switch- Ensure all children are vaccinated ( avoid tOPV

stock-outs before and bOPV stock-outs after the switch)

- Validate that the country is free tOPV.

Rationale for introducing single dose of IPV at 14 weeks

• IPV administration is recommended at 14 weeks of age because it provide the optimal balance between vaccine efficacy and early protection.

• If one dose of IPV is used, it should be given from 14 weeks of age because this is the age point when maternal antibodies have diminished and immunogenicity is significantly higher.

Administering IPV earlier than 14 weeks of age is not recommended because:

• Evidence suggest that a dose of IPV given at DPT1 contact protects only 32-39% of infants aged 6-8 weeks against poliovirus type2.

• In contrast, If the dose is given at DPT3 contact when the infant is 16 wks old (4 months), it protects about 63% of infants. 6-8

weeks16

weeks

0

10

20

30

40

50

60

70

Immune response of one dose of IPV against

type 2 poliovirus

63%

32%

Risks associated with introducing IPV later than 14 wks include:

• Administering IPV at later immunization visits is not recommended as it leaves children unprotected for a longer period of time.

• Children entering the routine immunization programme late should be given IPV at the first immunization contact after 14 weeks of age.

Key Facts about IPV:• Type: Inactivated (killed) poliovirus vaccine

(IPV) with types 1, 2 and 3 antigens.

• Formulation: IPV may contain formaldehyde as well as traces of streptomycin, neomycin or polymyxin also in some contain 2-phenoxyethanol (0.5%) as preservative. IPV formulation do not contain thiomersal.

• Composition : each dose contains (active ingredients, produced in VERO cells)

- Type 1 Mahoney (inactivated)-40 D antigen unit- Type 2 MEF-1 (inactivated)-8 D antigen unit- Type 3 Saukett (inactivated)-32 D antigen unit

• Presentation and dosage form: IPV is liquid vaccine, will be available in 5 dose or 10 dose vials.

• The colour of VVM on IPV vial changes faster than the other Vaccines.

• Storage temperature:- IPV is freeze - sensitive vaccine. - Stored at temp +2 and +8 degree Centigrate in basket of an ILR.- Do not freeze IPV.- Maximum of 1 month is recommended for storage of IPV in a

health facility.- The ‘Shake test’ is not applicable to IPV vaccine (no aluminium

adjuvant). So discard the vial if there is any doubt of vaccine getting frozen.

• Contraindications: should not be given in children with known allergy to streptomycin, neomycin or polymyxin B, or with a history of an allergic reaction following previous injection of IPV.

• Age group : 14 weeks (3 ½ months) to maximum upto 1 year of age.

• Dosage and route : i/m in anterolateral aspect of mid-thigh ( Right thigh)

• Immunogenecity efficacy and effectiveness:- Immunogenecity of IPV schedules depends on the age

at administration, in addition to number of doses, due to interference by maternal antibodies.

-IPV can reduce the quantity and duration of virus shedding in stool samples, which may contribute to a reduction in transmission.

Sequence of vaccination at 14 weeks

OPV IPV PENTAVALENT

IPV vaccine will be introduced in the UIP in a phased manner:

• In phase 1 : 17 states + 4 union territories in Nov 2015.

ArunachalPradesh, Assam, Bihar, Chandigarh, Delhi, Gujarat, Haryana, M.P, Manipur, Meghalaya, Mizoram, Nagaland, Punjab, Rajasthan, Sikkim, Tripura And U.P.

- Andaman & Nicobar Islands, Dadar & Nagar Haveli, Daman & Diu and Lakshadweep.

• In phase II- 9 states in January 2016- States include Chhattisgarh, Goa , Himachal

Pradesh, J&K, Jharkhand Maharashtra, Odisha, Uttrakhand and West Bengal.

• In phase III- 6 states / UT in march 2016. AndhraPradesh, Karnataka, Kerala, Pondicherry,

Tamil Nadu & Telangana.

AFP surveillanceNationwide AFP (acute flaccid paralysis) surveillance is the gold

standard for detecting cases of poliomyelitis. Surveillance identifies new cases and detects importation of

wild poliovirus.

The four steps of surveillance are:

1. Finding and reporting children with acute flaccid paralysis (AFP)

2. Transporting stool samples for analysis 3. Isolating and identifying poliovirus in the laboratory 4. Mapping the virus to determine the origin of the virus

strain.

Finding and reporting children with acute flaccid paralysis (AFP) surveillance:

• The first links in the surveillance chain are staff in all health facilities- from district health centres to large hospitals.

• They must promptly report every case of AFP in any child under 15 years of age.

• The number of AFP cases reported each year is used as an indicators of a country’s ability to detect polio-even in countries where disease no longer occurs.

• A country’s surveillance system needs to be sensitive enough to detect at least one case of AFP for every 100,000 children under 15- even in absence of polio.

Transporting stool samples for analysis

• Polio may be difficult to differentiate from Guillain-barre syndrome, transverse myelitis or traumatic neuritis.

• All AFP cases should be reported and tested for wild poliovirus within 48 hrs of onset.

• Faecal specimen are analyzed for the presence of polio.• Because shedding of the virus is variable, two specimens

taken 24-48 hrs apart are required.• Stool specimens have to be sealed in containers and stored

immediately inside a refrigerator or packed between frozen ice packs at 4-8 degree centigrade in a cold box.

• Specimen should arrive at the lab within 72 hrs of collection.

Isolating poliovirus

• If poliovirus is isolated the next step is to distinguish between wild and vaccine related.

• If wild polio virus is isolated then identify which of the two surviving types of wild virus is involved.

Mapping the virus• Once wild poliovirus has been identified further tests are

carried out to determine where the strain may have originated.

• By determining the genetic makeup of virus wild virus can be compared to others and classified into genetic families which cluster in defined geographic areas.

• When polio has been pinpointed to a precise geographical area, it is possible to identify the source of importation of poliovirus- both long range and cross border.

Environmental surveillance• Environmental surveillance involves testing sewage or

other environmental samples for the presence of poliovirus.

• Environmental surveillance often confirms wild poliovirus infections in the absence of cases of paralysis.

• Systematic environmental sampling provides important supplementary surveillance data.

• Ad-hoc environmental surveillance elsewhere (especially in polio-free regions) provides insights into the international spread of poliovirus.

Surveillance Indicators

EPIDEMIOLOGICAL INVESTIGATIONS

• Occurrence of single case of polio is considered epidemic .

• There is a need for prompt and immediate epidemiological investigation

• Active search for other cases is necessary• Sample of faeces from all cases or suspected

cases should be collected and forwarded to laboratory for virus isolation

• In addition where possible, Paired sera should be collected 1st sample at the clinical suspicion of paralytic polio & at period of convalescence.

• Within an epidemic area OPV administered for all persons over 6 weeks of age who have been not completely immunised or their immune status is not known .

• WHO should be notified as soon as possible of the occurrence of paralytic polio.

STRATERGIES OF POLIO ERADICATION IN INDIA

• Conduct pulse polio immunisation days every year until poliomyelitis is eradicated .

• Sustain high levels of routine immunisation coverage .• Monitor OPV coverage at district level & below.• Improve surveillance capable of detecting all cases of AFP due to

polio & non-polio aetiology.• Ensure rapid case investigation & collection of stool samples for

virus isolation.• Arrange follow up of all cases of AFP at 60 days to check for residual

paralysis .• Conduct outbreak control for cases confirmed or suspected to be

poliomyelitis to stop transmission

LINE LISTING OF CASES

Started in year 1989 to look for

1.Check for duplication 2.Year of onset of illness ( to screen children with residual

paralysis who developed poliomyelitis prior to year of reporting ).

3.Identification of high risk pockets 4. And documentation of high risk age groups .

Line listing of cases made it possible to take appropriate follow –up action in areas from where cases have been reported , also provides useful epidemiological data for programme purpose .

MOPPING UP

• This activity is last in polio eradication • Mopping up involves door to door

immunisation in high risk districts , where wild poliovirus is known or suspected to be still circulating .

Pulse polio immunisation

• In India NIDs have become the largest public health campaign ever conducted in a single country.

• GOI conducted the first round of PPI consisting of 2 immunization days 6 wks apart on 9th dec 1995 and 20th jan 1996.

• Targeted all children upto 3 yrs later on WHO increases age upto 5 yrs.

• The term PULSE has been added to describe this sudden, simultaneous , mass administration of OPV on a single day to all children 0-5 yrs of age, regardless to previous immunization.

• PPI occurs in two rounds about 4-6 wks apart during low transmission season of polio , i.e. Between nov to feb.

• These doses are extra dose which supplements and do not replace the doses received during immunization services.

• There is no minimum interval between PPI and scheduled OPV doses

Thank you…