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, High transmission season Any 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 Network 2011* Reporting site N=33,114 *Data as on 10 July 2011 No. of Reporting Sites

Non-polio AFP rate * Target: > 2 per 100,000 popn.<15 years Year to date comparison AFP cases in 2011 vs in 2010 Year to date 8.34 *Data as on 10 July 2011

% stool collection within 14 days * 83% 84% Target: > 80% *Data as on 10 July 2011

Stool Specimens processed in polio laboratories - India Number of specimen processed * 65,01191,148100,102109,09883,528 *Data as on 10 July 2011 >55,000 AFP cases investigated in 2010

Mean number of days from stool received in laboratory to final result of Wild and Vaccine viruses *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 % adequate stool collection Non-polio AFP rate HR blocks U.P Bihar U.P. 82% Bihar 88% *Data as on 10 July 2011 U.P. HR Bihar HR 54.4 U.P. HR 83% Bihar 89

Surveillance in recent transmission areas West Bengal, Jharkhand & Maharashtra

WB & Jharkhand Non-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*

WB & Jharkhand % adequate stool collection *Data as on 10 July 2011 Jharkhand 82% West Bengal 87% Jharkhand 82% West Bengal 86% 2010

Maharashtra *Data as on 10 July Non-polio AFP rate, 2011* 2010* 2011* Year to date No. of AFP cases

Maharashtra *Data as on 10 July % 2011* % adequate stool collection %

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, WPV1 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: months)

Quality of surveillance in districts with orphan viruses >1% genetic distance, Jan 2010 – June 2011 Non-polio AFP rate% adequate stool collection *Data as on 10 July 2011

Districts with ‘Orphan’ viruses, WPV1 from 8 districts 1 isolate each in Mumbai & Delhi sewage WPV1 cases with >1% Genetic distance WPV1 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 * 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 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 : High risk: > 8 importations and > 5 years with importations Medium risk: : > 5 importations and years with importations State TotalRisk Haryana High Delhi Uttarakhand Maharashtra West Bengal Punjab Rajasthan Medium Gujarat151 7 Jharkhand Madhya Pradesh Assam Low Orissa 12 3 Andhra Pradesh 11 2 Himachal Pradesh Jammu & Kashmir 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, *: data as on 12 March 2011 DELHI HARYANAMEWAT UTTARAKHANDHARDWAR ANDHRA PRADESHEAST GODAVARI HARYANAFARIDABAD HARYANAHISAR HARYANAJHAJJAR HARYANAPANCHKULA HARYANAPANIPAT JAMMU & KASHMIRJAMMU JHARKHANDPAKUR MAHARASHTRABEED MAHARASHTRAGR. MUMBAI MAHARASHTRATHANE PUNJABLUDHIANA PUNJABMOGA PUNJABPATIALA RAJASTHANBHARATPUR UTTARAKHANDUDHAMSINGH NAGAR WEST BENGAL24-PARGANAS SOUTH WEST BENGALHOWRA WEST BENGALMURSHIDABAD ASSAMKARIMGANJ HARYANASONEPAT MAHARASHTRANASIK PUNJABHOSHIARPUR UTTARAKHANDDEHARADUN

Surveillance in Districts with high risk of importation Non-polio AFP rate, 2011* *Data as on 10 July 2011

Enhanced Surveillance Among Migrants Year to date comparisons of reported AFP cases India UP & Bihar 6 States at high risk of importations *Data as on 10 July 2011

Non-polio AFP cases in migrants Estimated non-polio AFP rate** amongst migrants * N=691 N=1588 *Data as on 10 July 2011 ** Estimate based on the number of migrant children vaccinated in SIAs

Sewage sampling sites 2010 Sewage sampling initiated 2011 State planned for 2011 States planned for 2012 Further expansion of sites in Delhi & Maharashtra Expansion of Environmental Surveillance in High Importation Risk Areas

Surveillance quality assurance Ongoing surveillance reviews

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 Number of sensitization visits No. of AFP surveillance workshops, * Outcome: Increased number of AFP cases reported *Data as on 10 July No. of AFP Cases Reported

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.

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