Poliovirus Surveillance and Risks to Polio Eradication in India

Poliovirus Surveillance and Risks to Polio Eradication in

India

Dr. Hamid Jafari

WHO-NPSP

Risks to Polio Eradication in India

• Reintroduction of virus into traditional endemic areas of UP and Bihar– Persistent circulation in areas with recent

transmission (West Bengal, Jharkhand) spreading back to endemic areas

– Survival of poliovirus in the migrant and mobile communities leading to further spread

• International importation

• Persistent undetected transmission in traditional reservoir areas of UP and Bihar

Risks to Polio Eradication in India - II

• Introduction and survival of poliovirus in areas with low population immunity and/or other transmission risk factors outside UP and Bihar

• Gaps in AFP surveillance or delays in detection of WPV

• Delayed and/or inadequate response to importation

Monthly incidence of WPV1 cases, 2005-2011

High transmission seasonAny residual WPV transmission is likely to be detected in the coming High Season for Polio

Presentation - Key Questions • Is the overall sensitivity and timeliness of AFP

surveillance adequate?

• How robust is surveillance in the traditional endemic states of UP and Bihar?

• What is the quality of surveillance in areas with recent transmission?

• What is the quality of surveillance in areas where ‘orphan viruses’ have been isolated?

• What is being done to enhance surveillance for poliovirus?

AFP Surveillance Reporting Network2011*

Reporting site

N=33,114

*Data as on 10 July 2011

No. of Reporting Sites

21403

26036

27919

2993230595

31269

32877 33114

15000

20000

25000

30000

35000

2004 2005 2006 2007 2008 2009 2010 2011*

Non-polio AFP rate

2010 2011*

12.64 8.63

Target: > 2 per 100,000 popn.<15 years

Year to date comparison

22973 AFP cases in 2011 vs. 22070 in 2010

Year to date

8.34

*Data as on 10 July 2011

% stool collection within 14 days

2010 2011*

83% 84%

IndiaLess than 60%60% to 69%70% to 79%80% and aboveNo AFP case

Target: > 80%

*Data as on 10 July 2011

Stool Specimens processed in polio laboratories - India

2006 2007 2008

Number of specimen processed

2009 2010 2011*

65,011 91,148 100,102 109,09883,528

*Data as on 10 July 2011

>55,000 AFP cases investigated in 2010

0

10

20

30

40

J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M

Mean number of days from stool received in laboratory to final result of Wild and Vaccine viruses

2006 2007 2008 2009 2010 2011

*Data as on 10 July 2011

Overall sensitivity and timeliness of AFP surveillance

The overall sensitivity and timeliness of AFP and laboratory surveillance has continued to improve, however, some

areas need further improvements

Surveillance in endemic states Bihar & Uttar Pradesh

Non-HR blocks

Quality indicators, Bihar & UP, 2011

Non HR blocks

IndiaLess than 60%60% to 69%70% to 79%80% and aboveNo AFP case

% adequate stool collection

Non-polio AFP rate

HR blocksU.P.

16.59

Bihar

28.78

U.P.

82%

Bihar

88%*Data as on 10 July 2011

U.P. HR

37.15

Bihar HR

54.4

U.P. HR

83%

Bihar

89

Surveillance in recent transmission areasWest Bengal, Jharkhand & Maharashtra

WB & JharkhandNon-polio AFP rate, 2011*

*Data as on 10 July 2011

Jharkhand

7.26

West Bengal

4.35

Year to date No. of AFP cases

West Bengal

Jharkhand

2010* 2011*

2011*

WB & Jharkhand% adequate stool collection

*Data as on 10 July 2011

Jharkhand

82%

West Bengal

87%

Jharkhand

82%

West Bengal

86%

2010

IndiaLess than 60%60% to 69%70% to 79%80% and aboveNo AFP case

Maharashtra

*Data as on 10 July 2011

4.41

Non-polio AFP rate, 2011*

2010* 2011*

Year to date No. of AFP cases

Maharashtra

IndiaLess than 60%60% to 69%70% to 79%80% and aboveNo AFP case

*Data as on 10 July 2011

83%

2011*

% adequate stool collection

2010

84%

• Surveillance in the traditional endemic states of UP and Bihar:

Surveillance in endemic states is of excellent quality with very high case reporting rates in high risk blocks

• Quality of surveillance in areas with recent transmission

AFP case reporting has increased in 2011 compared with 2010, however, a few key districts need further improvements, especially in adequate sample collection

Surveillance in areas with ‘orphan’ wild polioviruses

Example: Orphan WPV1 detected in UP

Transmission detected after a gap of 13 months

>1.5% genetic distance

Districts with ‘Orphan’ viruses, 2008-2010WPV1 cases with >1% Genetic distance

28 Orphan WPV1 isolated in 23 districts 1 isolate each in Mumbai & Delhi sewage

4 districts where same genetic strain detected more than once (interval range: 8-10 months)

Quality of surveillance in districts with orphan viruses>1% genetic distance, Jan 2010 – June 2011

Non-polio AFP rate % adequate stool collection

IndiaLess than 60%60% to 69%70% to 79%80% and aboveNo AFP case*Data as on 10 July 2011

Districts with ‘Orphan’ viruses, 2008-2010

10 WPV1 from 8 districts1 isolate each in Mumbai & Delhi sewage

WPV1 cases with >1% Genetic distanceWPV1 cases with >1.5% Genetic distance

Quality of surveillance in districts with orphan viruses>1.5% genetic distance

Non-polio AFP rate

*Data as on 10 July 2011

2008 Bihar WPV1 in Saharsa

Virus detection intervals: 10 monthsVirus detection intervals: 10 months and 9 months

The single 2008 Saharsa isolate ancestor of all

subsequent WPV1 strains

Enhanced Surveillance in Kosi River Area

* data as on 10 July 2011

2011*2010200920082007

2008 WPV1 case in Kosi River area

No. of AFP cases

Surveillance in Districts with ‘Orphan’ WPV Isolates

• Most Districts with orphan strains have strong surveillance and are unlikely hosts of prolonged undetected transmission

• Kosi River area of Bihar was the most likely region with undetected transmission until 2009, however, surveillance has been enhanced substantially in this area

• Many orphan strains likely related to transmission among migrants or in immune populations

• Isolation of orphan strains in Murshidabad and Nasik districts in 2010 highlight the need for further surveillance improvements in these districts

Special Strategies to Enhance Surveillance

Role of Migrants in Survival and Spread of Poliovirus

Example of most recent WPV1 case

Uttar Pradesh

(N= 118)

Bihar

(N= 90)

Migration status of WPV1 cases 2007-11

Rest of India

(N= 48)

Non epidemic UP*

(N= 56)

*Non epidemic UP excludes Moradabad, JP Nagar, Badaun, Kanshiram Nagar, Bareilly and Rampur districts*Data as on 10 July 2011

Pattern of importations of WPV : 2005-11

High risk: > 8 importations and > 5 years with importations

Medium risk: : > 5 importations and 3 - 4 years with importations

State 2005 2006 2007 2008 2009 2010 2011 Total Risk

Haryana 1 10 5 2 2     20

High

Delhi 1 5 2 5 4 2   19

Uttarakhand 1 8 4 1 2     16

Maharashtra 4 4 1 2   1   12

West Bengal   2 2 1   3 1 9

Punjab 1 3 1 1 2     8

Rajasthan   1 2 2 3     8

MediumGujarat 1 5 1         7

Jharkhand 2 1     2 1   6

Madhya Pradesh   4   1       5  

Assam   2   1       3

Low

Orissa     1 2       3

Andhra Pradesh     1 1       2

Himachal Pradesh   1     1     2

Jammu & Kashmir   1       1   2

Karnataka     1         1

Importations in >=4 years

Importations in 2-3 years

Importation in a year with multiple cases

No importation or importation in a year with single case

Risk of WPV importation - outside UP & Bihar, 2005-11

*: data as on 12 March 2011

DELHI DELHI

HARYANA MEWAT

UTTARAKHAND HARDWAR

ANDHRA PRADESH EAST GODAVARI

HARYANA FARIDABAD

HARYANA HISAR

HARYANA JHAJJAR

HARYANA PANCHKULA

HARYANA PANIPAT

JAMMU & KASHMIR JAMMU

JHARKHAND PAKUR

MAHARASHTRA BEED

MAHARASHTRA GR. MUMBAI

MAHARASHTRA THANE

PUNJAB LUDHIANA

PUNJAB MOGA

PUNJAB PATIALA

RAJASTHAN BHARATPUR

UTTARAKHAND UDHAMSINGH NAGAR

WEST BENGAL 24-PARGANAS SOUTH

WEST BENGAL HOWRA

WEST BENGAL MURSHIDABAD

ASSAM KARIMGANJ

HARYANA SONEPAT

MAHARASHTRA NASIK

PUNJAB HOSHIARPUR

UTTARAKHAND DEHARADUN

Enhanced Surveillance Among MigrantsYear to date comparisons of reported AFP cases

India

UP & Bihar 6 States at high risk of importations

445

638 691

2009 2010 2011

126

208 205

2009 2010 2011

266305

397

2009 2010 2011

*Data as on 10 July 2011

Non-polio AFP cases in migrants

Estimated non-polio AFP rate**amongst migrants

2010 2011*N=691N=1588

9.01

12.46

9.18

2009 2010 2011**Data as on 10 July 2011

** Estimate based on the number of migrant children vaccinated in SIAs

Sewage sampling sites 2010Sewage sampling initiated 2011State planned for 2011States planned for 2012

Further expansion of sites in Delhi & Maharashtra

Expansion of Environmental Surveillance in High Importation Risk Areas

RAJASTHAN

ORISSA

GUJARAT

MAHARASHTRA

MADHYA PRADESH

BIHAR

KARNATAKA

UTTAR PRADESH

ANDHRA PRADESH

JAMMU & KASHMIR

ASSAM

TAMIL NADU

CHHATTISGARH

PUNJAB

JHARKHAND

WEST BENGAL

ARUNACHAL PR.

HARYANA

KERALA

UTTARANCHAL

HIMACHALPRADESH

MANIPUR

MIZORAM

MEGHALAYA

NAGALAND

TRIPURA

SIKKIM

GOA

A&N ISLANDS

DL

D&N HAVELIDAMAN & DIU

PONDICHERRYLAKSHADW EEP

CH

Surveillance quality assuranceOngoing surveillance reviews

2011

RAJASTHAN

ORISSA

GUJARAT

MAHARASHTRA

MADHYA PRADESH

BIHAR

KARNATAKA

UTTAR PRADESH

ANDHRA PRADESH

JAMMU & KASHMIR

ASSAM

TAMIL NADU

CHHATTISGARH

PUNJAB

JHARKHAND

WEST BENGAL

ARUNACHAL PR.

HARYANA

KERALA

UTTARANCHAL

HIMACHALPRADESH

MANIPUR

MIZORAM

MEGHALAYA

NAGALAND

TRIPURA

SIKKIM

GOA

A&N ISLANDS

DL

D&N HAVELIDAMAN & DIU

PONDICHERRYLAKSHADW EEP

CH

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2010

Example: Delhi surveillance review 2010,Key concerns

• Inadequate informer network in areas with migrants

• Need for further sensitization of reporting network

Number of reporting sites

182 187

288

183

2008 2009 2010 2011

Number of sensitization visits No. of AFP surveillance workshops, 2011

31

5343 47

15 20

36

135

19

33

16

68

84

100

5242

J F M A M J J A S O N D J F M A M

1215

9

4 57

Jan Feb Mar Apr May Jun

0

10

20

30

40

50

60

J an Feb Mar Apr May J un J ul Aug Sep Oct Nov Dec J an Feb Mar Apr May J un J ul Aug Sep Oct Nov Dec J an Feb Mar Apr May J un

2009 2010 2011*

Outcome: Increased number of AFP cases reported

*Data as on 10 July 2011

2010 2011

No.

of

AF

P C

ases

Rep

orte

d

Special Surveillance Strategies

• Special efforts ongoing to measure and increase surveillance among migrants

• Expansion of environmental surveillance guided by risk of importation

• Ongoing independent surveillance reviews targeted to high risk areas and populations

• Assessment of local surveillance quality will be a key component of the ongoing risk analyses by states as they develop their polio emergency and response plans

Summary• Overall, a sensitive surveillance system that

meets or exceeds international standards

• A reliable and efficient laboratory network despite an increasingly heavy workload

• High AFP reporting rates in endemic states, particularly in high risk blocks

• Improvements in case reporting in areas with transmission in 2010, however, a few districts need further strengthening

• Any residual transmission is likely to be detected in the ensuing high season for polio

Summary• Orphan strains have been detected after an interval of up to 13 months very

recently.

• Migrants have contributed significantly to undetected transmission

• Focused efforts ongoing to promptly detect transmission in migrant populations

• Expansion of environmental surveillance will help early detection of virus in high risk areas

• Most districts with orphan isolates have strong surveillance. Surveillance in Kosi River area has improved substantially.

Thank You