Current Strategies for eradication of polio

Current Strategies for
eradication of polio

SPEAKER :- PREETI RAI
TEACHER I/C:- Dr. Dheeraj
Mahajan
DATE :- 31 / 12 / 2013
1

What is polio?
The words polio (grey) and myelon (marrow,
indicating the spinal cord) are derived from
the Greek. It is the effect of poliomyelitis virus
on the spinal cord that leads to the classic
manifestation of paralysis.

History of polio…
The disease of poliomyelitis
has a long history. The first
example may even have been
more than 3000 years ago. An
Egyptian stele dating from the
18th Egyptian dynasty (1580 1350 BCE) shows a priest
with a deformity of his leg
characteristic of the flaccid
paralysis typical of
poliomyelitis.

.

In the 1940s and 1950s “iron lungs” were used to
regulate breathing and keep polio patients alive.

PROBLEM STATEMENT
• When the World Health Assembly launched the Global
Polio Eradication Initiative (GPEI) in 1988, it was widely
acknowledged that India would be one of the most
challenging countries for polio eradication.
• By 2006, Afghanistan, India, Nigeria, and Pakistan were
the only remaining polio endemic countries .Since the
GPEI was launched, the number of cases has fallen by
over 99%.
• In 2013, only three countries in the world remain polioendemic: Nigeria, Pakistan and Afghanistan

• In the mid-1990s, an estimated 150,000 polio cases
were reported annually in India.
• The last case of polio was reported on 13th January
2011 from West Bengal and further no case of polio
has been reported in the country since then.
• . India has been polio free for more then a year and
was removed from the Endemic.
• P2 Wild Polio Virus eradicate from the world in 1999

Number of polio cases worldwide from 2000 to 2010

Current Strategies for eradication of polio

Number of polio cases from 1998 to 2013.

Despite very high coverage during immunization activities & intensive use
of mOPV1, transmission of type-1 WPV has persisted in U.P. & Bihar



Last wild poliovirus type 1 (WPV1) case: 13 January
2011, Howrah, West Bengal

Last wild poliovirus type 2 (WPV2) case: October 1999,
Aligarh, Uttar Pradesh
Last wild poliovirus type 3 (WPV3) case: 22 October
2010, Pakur, Jharkhand
Last positive case from monthly environmental sewage
sampling (conducted in Delhi, Mumbai and Patna):
November 2010, Mumbai .

EPIDEMIOLOGY
•
•
•
•

AGENT: POLIOVIRUS
TYPE : THREE SERO TYPES(TYPE-1,TYPE-2,TYPE-3)
RESERVOIR: HUMAN ONLY
INFECTIOUS MATERIAL: FAECES, OROPHARYNGEAL SECRETIONS
• PERIOD OF COMMUNICABILITY: 7 TO 10 DAYS
BEFORE AND AFTER ONSET OF SYMPTOMS
• AGE : 6 MONTHS TO 3 YEARS ARE MOST
VOLUNERABLE

• ENVIRONMENT : RAINY SEASON (JUNE TO
SEPTEMBER)
• MODE OF TRANSMISSION: FAECO – ORAL ROUTE,
DROPLET INFECTION.
• FAVOURABLE CONDITIONS: OVER CROWDING,POOR
SANITATION,SLUMS
• INCUBATION PERIOD: 7 TO 14 DAYS( 3- 35 DAYS)

POLIO VIRUS
THREE TYPES
• TYPE-1—EPEDEMICS causes outbreaks—is the most
likely virus to cause paralysis.
• TYPE-2---THIS IS THE FIRST SERO TYPE TO
DISAPPEAR.
• TYPE-3--- PARALYSIS LESS FREQUENT.

Clinical Spectrum of Polio
• Asymptomatic =inapparent=subclinical91-96%
• Minor non CNS=Abortive polio illness4-8%Aseptic meningitis =NON paralytic polio-1% stiffness
and pain in neck n back
• Paralytic Polio<1% ,Asymmetrical flaccid paralysis and fever at the time
of onset of paralysis
• Among children who are paralyzed by polio:
30% make a full recovery
30% are left with mild paralysis
30% have medium to severe paralysis
10% die

IPV (Salk)


killed formolised virus

OPV (Sabin)


live attenuated virus

Given SC or IM

 given orally

Induces circulating antibodies, but

 immunity is both humoral and

not local (intestinal immunity)
Prevents paralysis but does not
prevent reinfection
Not useful in controlling epidemics
More difficult to manufacture and is
relatively costly

intestinal. induces antibody quickly
Prevents paralysis and prevents
reinfection
Can be effectively used in controlling
epidemics.
Easy to manufacture and is cheaper

>90% immune after 2 doses
Duration of immunity not known with
certainty

 50% immune after 1 dose
Immunity probably lifelong

VDPV
Vaccine-derived polioviruses (VDPVs) are rare but welldocumented strains of poliovirus ,which emerge after
prolonged multiplication of attenuated strains of the
virus contained in the oral polio vaccine (OPV) in the guts
of children with immunodeficiency or in populations with
very low immunity.
In1999-2000 it was proven that vaccine-derived
polioviruses (VDPVs) could regain the capacity to cause
polio outbreaks (i.e. become circulating VDPVs or
cVDPVs).

The management of VDPVs is a necessary part of the
global polio eradication effort, and is similar to
management of wild poliovirus outbreaks; i.e. by rapid
implementation of high-quality SIAs. Global experience
with VDPVs shows that they can be rapidly stopped,
with 2-3 rounds of high-quality, large scale immunization
rounds.

The Global Polio
Eradication Initiative

Four Pillars of the Global Polio Eradication
Initiative Strategy
1. Routine Immunization 1985
2. Supplemental Immunization Activities
1995-96
3. Acute Flaccid Paralysis (AFP) Surveillance 1997
4. Targeted Mop-Up Campaigns

WHY POLIO IS A CANDIDATE FOR ERADICATION ?

Four Pillars of the Global Polio Eradication Initiative Strategy
1. Routine Immunization 1985
• A major cornerstone of the polio eradication strategy is
ensuring that at least 80% of children receive all the
recommended routine childhood immunizations.
• Good routine OPV coverage increases population immunity,
reduces the incidence of polio and makes eradication
feasible plan of routine immunization for out reach areas.
.

According to WHO/UNICEF immunization coverage
estimates, 86% of infants received three doses of oral
polio vaccine in 2010, compared with 75% in 1990.

2. Supplemental Immunization Activities 1995-96
• Mass polio immunization campaigns that
complement routine immunization programs are
intended to interrupt transmission by immunizing
every child under the age of 5 with oral polio
vaccine annually, regardless of the number of
times they have been immunized previously.
• These campaigns help protect children who are
not immunized or only partially protected and
boost the immunity of those who are immunized,
thereby reducing or eliminating the pool of
potential hosts.

WHAT IS PULSE POLIO ?

TO IMMUNIZE ALL THE KIDS< 5YRS NATION WIDE
ON A SINGLE DAY IN THE SHORTEST POSSIBLE TIME
WITH OPV & THAT THE ENVIRONMENT WILL GET
SATURATED WITH THE VACCINE VIRUS SO THAT IT
WILL REPLACE THE WILD VIRUS AND THUS
INTERUPT THE TRANSMISSION OF WILD VIRUS .



National Immunization Days (NIDs) - which are conducted
countrywide 2 or 3 times per year, 1 month apart.

 National Immunization Days are conducted in two rounds, one
month apart. Because oral polio vaccine does not require a
needle and syringe, volunteers with minimal training can serve
as vaccinators.

 Three to five years of NIDs are usually required to eradicate
polio, but some countries require more time, especially those
where routine immunization coverage is low.
 NIDs are normally conducted during the cool, dry season
because logistics are simplified, immunological response to oral
polio vaccine is improved and the potential damage to heatsensitive vaccine is reduced.

Synchronized NIDs
Neighbouring countries are coordinating, or "synchronizing" their
National Immunization Days. This ensures that children crossing
borders for any reason are identified and immunized. It also allows
health teams to cross borders and immunize children in pockets of
territory otherwise isolated by rivers or mountains, or on islands
that may be less accessible from the other side.
This approach was first used between countries of eastern Europe
and central Asia, in a successful campaign called "Operation
MECACAR."
Similar synchronized efforts have been undertaken along the
borders of Afghanistan and Pakistan.

• 3. Acute Flaccid Paralysis (AFP) Surveillance -1997
• As many as 90% of people infected with the poliovirus
experience very mild or no symptoms.
• A single symptomatic case can therefore represent a
significant community-wide outbreak. Robust
surveillance to detect and investigate every case of
polio-like AFP is essential to polio eradication.

AFP case definition broadened
Consequences of missing the case of polio are
more serious then occasionally including and
“ambiguous’’ case, specially during the final
stage of polio eradication.
Includes every case with
 current flaccid paralysis
 History of flaccid paralysis in the current illness

 Boarder line and ambiguous case
 Transient weakness / paralysis

AIM OF AFP SURVEILLANCE
TO DETECT POLIO TRANSMISSION & INTERRUPTION OF
TRANSMISSION
AFP CASE
POLIO CASE
RESERVOIR OF INFECTION
[ 100 TO 1000 SUB CLINICAL CASES ]

CONTAINMENT MEASURES
[ O.R.I. / MOP UP ]

COMPONENTS OF AFP SURVEILANCE
1.The AFP surveillance network and case notification
2.Case and laboratory investigation
3.Outbreak response and active case search in the
community
4.60-day follow-up, cross-notification
and tracking of cases
5.Data management and case classification
6.Virologic case classification scheme
7. Surveillance performance indicators

The most important aspect of this classification is the collection of
2 adequate stool samples from all cases. Samples are considered
adequate if both the specimens.
(1) are collected within 14 days of paralysis onset and at least 24
hours apart.
(2) are of adequate volume (8-10g) and
(3) arrives at a WHO-accredited laboratory in good condition (ie,
no desiccation, no leakage), with adequate documentation and
evidence of cold-chain maintenance.

AFP Reporting Network
Paediatrician

Neurologist

Physician

Gen. Pract.

Dist. Hospital
PHC
RH
MPW/ ANM
Traditional Healer
Quack

DHO/
MOH/
SMO

State
Delhi

WHO

Flow Diagram of AFP Case Investigation

WHY AFP SURVEILLANCE INSTEAD OF
POLIO SURVEILLANCE ?
• SURVEILLANCE OF A POLIO CASE ALONE IS NOT
SUFFICIENT BECAUSE IT IS IMPOSSIBLEE TO PRECISELY
IDENTIFY ALL CASES OF POLIO CLINICALLY DUE TO
CONFUSING AND AMBIGUOUS CLINICAL SIGNS AND
VARIABLE CLINICAL KNOWLEDGE & SKILLS OF DOCTOR.
• CLINICALLY POLIO IN ACUTE STAGE, IS DIFFICULT TO
DISTINGUISH FROM OTHER CAUSES OF ACUTE ONSET OF
FLACCID PARALYSIS.

When too much polio is around…..

AFP cases
Polio cases
Borderline AFP cases
Non-AFP cases

Surveillance
sensitivity is
adequate enough
to detect 90%
polio cases

Data Flow
Mondays

Reporting Units
Tuesdays
Districts
Wednesdays
States
Thursday
Delhi

Districts
State
NPSU Delhi
WHO

Outbreak Response Immunization (ORI)


Measures to stop transmission of polio virus
Children <5 yrs in the locality are given one dose of
OPV regardless of the number of doses received
previously.



A house-to-house active case search is conducted
to find additional AFP cases that may have occurred

AFP Surveillance is in the end
the only indicator for success

4. Targeted Mop-Up Campaigns
 Last stage in polio eradication
Low routine immunization coverage, very dense
or mobile populations, inadequate sanitation, and
poor access to health services exacerbate
communities’ vulnerability to polio.
 In focal areas where polio cases have been
confirmed within the previous 3 years and
circulating virus is confirmed or suspected.
In mop-up campaigns vaccinators go house-tohouse to immunize every child under 5 and help
to stop transmission.

Before a WHO region can be certified polio-free, three
conditions must be satisfied:
(A) AT LEAST THREE YEARS OF ZERO POLIO CASES DUE TO WILD
POLIOVIRUS
(B) EXCELLENT CERTIFICATION STANDARD SURVEILLANCE

(C) EACH COUNTRY MUST ILLUSTRATE THE CAPACITY TO DETECT,
REPORT AND RESPOND TO “IMPORTED” POLIO CASES.
LABORATORY STOCKS MUST BE CONTAINED AND SAFE
MANAGEMENT OF THE WILD VIRUS IN INACTIVATED POLIO
VACCINE (IPV) MANUFACTURING SITES MUST BE ASSURED
BEFORE THE WORLD CAN BE CERTIFIED POLIO-FREE.

Social Mobilization Network (SMNet)
 In Uttar Pradesh, India, in response to low routine
immunization coverage and ongoing poliovirus
circulation, Social Mobilization Network (SMNet) was
launched.
 The SMNet’s goal was to improve access and reduce
family and community resistance to vaccination in highrisk communities, encourage vaccination of children
missing scheduled vaccinations, and mobilize local
opinion leaders for promotion of vaccination awareness
about sanitation hygiene.
 Data suggest that the immunization coverage in SMNet
communities was often higher than overall coverage in
the district.

Current priorities for assessment
 Expanded Target Age Groups: expanding the
target age group for OPV beyond 5 years of age
in SIAs may accelerate the interruption of polio
transmission

 Inactivated Poliovirus Vaccine: there is
increasingly strong evidence that a
supplementary dose of IPV can substantially
boost mucosal immunity in OPV-vaccinated
populations, potentially accelerating
eradication.

Achievements of Polio Eradication Strategy
A. Reduction in Cases
B. Prevention of Disabilities and Deaths- More then 4 lac
polio cases prevented so far in India
(Over 20 years)
C. Medical Care Cost Savings
D. Enhanced Global Surveillance Capacity which could
support other public health Programmes.
E. Entero Virus Laboratory Network at par with Global
Standards

Risks/Challenges to Polio Eradication Strategy:
a) International Importation of wild polio virus. Neighboring
countries like Afghanistan, Pakistan and China has had a major
outbreak of Wild Polio Virus in 2011 who pose a major threat to
Polio.
b) The major barrier to eradication in Nigeria and Pakistan is
access—security fears have prevented health workers from
reaching the at-risk populations, and misplaced beliefs about
vaccine safety has led to vaccine refusal.
c) Gaps in AFP Surveillance or delays in detection of wild polio virus
d) Delayed and or inadequate response to importation.
.

e) Areas with low population immunity.
f) Gaps in Routine Immunization & SIA especially in High Risk
Areas
g) Various resident societies in Delhi are not allowing vaccinators
to enter their premises and immunize children in these
societies. They have myth that OPV is an anti-fertility vaccine
and would lead to impotence in male children or infect them
with AIDS.
h) Children in western UP from Muslim community have
consistently been missed both during SIAs and for routine
immunization. Significantly almost 66% of polio cases have
occurred among Muslim children.

The goal of the 2013-2018 Polio Eradication
and Endgame Strategic Plan is to complete
the eradication and containment of all wild,
vaccine-related and Sabin polioviruses, such
that no child ever again suffers paralytic
poliomyelitis

Conclusion
• At present, polio is endemic in three countries—Until
poliovirus transmission is interrupted in these
strongholds, all countries remain at risk, as shown not
only by the outbreak in Syria, but also in recurrent
outbreaks across sub-Saharan Africa, including an
ongoing outbreak in Somalia.
• The outbreak in Syria could have major health
consequences for other countries, and the government
there must assist in providing health-care workers and
aid organizations with access to at-risk populations.

• But the outbreak also serves as a reminder that high
vaccination coverage is essential in countries where
the disease is not currently circulating.
• Although it seems like a major setback to eradication
efforts, the polio outbreak in Syria might be used as
an opportunity to reinvigorate eradication campaigns
in Afghanistan, Nigeria, Pakistan, and surrounding
countries.

Reference:
1.
2.
3.
4.

www.npspindia.org
www.mohfw.nic.in www.polioeradication.org
www.unicef.org/immunization
Super course/ Pittsburgh
university(www.pitt.edu/~super1)
5. JIMA DECEMBER 2005
6. http://www.polionet.org/vaccine.htm
7. www.who.int

Current Strategies for eradication of polio

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