Poliovirus Surveillance and Risks to Polio Eradication in India Dr. Hamid Jafari WHO-NPSP
Jan 06, 2016
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