Naveen Thacker, Vipin M Vashishtha, Nitin K Shah.
Medical Science Department, Pediatric Oncall. | Current Status Of Polio Eradication in
India:
Number of wild polio cases decreased in India from 1126 in 1999 to 265 in 2000 and 268 in 2001. India experienced an epidemic of polio in 2002 when 1600 wild polio cases were reported. In 2003 only 225 cases were reported. In 2004, India reported the lowest ever number of polio cases- 136 against 225 in 2003.1 Wild virus transmission is now confined to extremely restricted geographical area of western UP and Bihar. More than 90% of cases occur in small clusters of districts in western UP and central Bihar. Immunization status of under-5 yr old children is best ever all over the country. Genetic diversity of Type 1 wild poliovirus (wPV) has now restricted to only 3 clusters. And all these are achieved against a background of highly improved AFP-surveillance in 2004 especially in UP and Bihar.
Western UP and Bihar still continue to be the most stubborn reservoirs. 13 districts in western UP and 16 in Bihar are labeled as 'code red' districts. These two regions have never remained polio free since the launch of National Polio Eradication Program in 1995. In UP number of wPV remained almost stationary-88 cases in 2003 and 82 in 2004! Western UP is the origin of almost all recent cases of wPV detected anywhere in the country. Again, the underserved young (< 2 years) children from Muslim community were mainly affected. Further, there remain quality gaps in SIA in critical high priority districts of UP, Bihar and Maharashtra, and consequently, up to 10% of children are still being missed in these highly endemic areas. The finding of 2 wPV cases in eastern UP (one case in the last week of 2004) has increased concern of the enforcing agencies. And in 2005-already 8 cases have been reported so far in January.1
On further analyzing the current national data, it is clear that in 2004, the disease mainly affected the children below 2 years of age (73%) hailing from Muslim community (79%) and majority of them had already received > 4 opv doses (83%). Interestingly in UP, the number of polio cases having > 4 doses were 93% whereas only 2% of them have received no opv dose at all! It means, the children of UP are better served by the ongoing program. This fact is further consolidated by viewing 'immunization gap' amongst non-polio AFP cases which is a better indicator of immunization coverage among general population (6 mo to 5 years old). The "immunization gap" in UP is merely 2% whereas some of the states like Assam (14%), Punjab (6%), Gujarat and Chhattisgarh (5% each) are having gaps in the immunization status of their children < 5 years even then they have not reported any case so far.2
We did indeed make some progress in 2004 in form of confining the wild virus in to its last stronghold of western UP and Bihar. In 2005, the highest priority would be how to demolish these two strongholds.
Reasons for failure to reach Zero polio status:
Detailed evaluation of surveillance, immunization coverage and sequencing data shows several factors contributed to this situation:- It is very high force of type 1 wild virus transmission amongst infants and toddlers, low vaccine efficacy, quality gaps in SIAs, and favorable environmental, geographical and demographical milieu in western UP. The main problem in Bihar is of poor accessibility due to natural calamity like frequent floods that hamper immunization activities in the state.
Poor Routine Immunization:
Although the reported opv3 coverage, as reported by the Government functionaries in most of the states of India have been better than 90 %, vaccination coverage data from AFP cases that were not caused by poliovirus suggest a deterioration in opv coverage in the general population of the majority of states with increased polio incidence in 2002, particularly in UP. A coverage evaluation by UNICEF indicates that in UP opv3 coverage in 1999-2000 was 35%, in 2000-2001, 50% and in 2001-2002 it was only 41%. In Bihar opv3 coverage in last four years is only between 21-25%. There is also decline in opv3 coverage from other states reporting polio like in Rajasthan opv3 coverage in 2002 was only 35%. This is leaving a vast pool of susceptible children.
Poor vaccine acceptance by Muslim Community :
Poor acceptance of opv immunization by Muslim community has further compounded the problem. Although organized resistance seen in 2002 is not seen now, still there are pockets of resistance to opv immunization in West UP. Recently there were few incidences of attacks on vaccination teams (Personal communication, Atul Agarwal). Children in western UP from Muslim community have consistently been missed both during SIAs and for routine immunization. Significantly almost 79% of polio cases in 2004 in UP have occurred among Muslim children. In west UP high-risk districts, there is still an immunization gap between Muslim and non-Muslim children.
Failure to Reach All Children:
Analysis of immunization status of non-polio AFP cases suggest that virus survived in West UP and central Bihar through low season of 2004 due to gaps in SIA implementation. High-risk districts in transmission areas still have relatively lower immunization status than other areas (although improving). This suggests that hundreds of thousands of children were missed in areas where high population density, a very large birth cohort, and poor sanitation favor poliovirus transmission. One major factor contributing to poor SIA quality in UP was inadequate engagement and involvement of the general community, particularly members of muslim groups.
Other Reasons:
Apart from high poverty and low levels of literacy, certain factors responsible for dissemination of other water-borne diseases such as over-crowding, poor sanitation and bad hygienic conditions and unavailability of safe drinking water are also operating in UP and Bihar. Additionally, waning media interest, fatigue owing to prolonged repetitive exercises, a dwindling public involvement, and lack of commitment of all sectors of local administration have hampered the progress of this mass-campaign in the most populous and political sensitive states of north India.
What can be done?
The first and foremost objective for this year is to urgently stop the wild virus transmission in the remaining reservoir areas while maintaining high level of immunity in children throughout the country.
India Expert Advisory Group on Polio (IEAG) has charted out plan to tackle specific problem with specific intervention.4 The issue of high force of transmission will be tackled by high speed and higher efficacy of SIAs. Now there will be 8 SIAs (NIDs And SNIDs) in endemic areas, meaning thereby, at least 8 doses of opv are assured to a child during first year of life. The issue of low vaccine efficacy is being tackled by improving the immune responses in vaccinees in order to enhance impact of SIAs. The use of monovalent-OPV type1 (m-OPV1) in place of trivalent opv starting from June this year in all reservoir and surrounding areas is perhaps the most significant intervention. The issue of quality gaps in SIAs will be dealt by improving the quality of these rounds. More emphasis will be given to cover the transient and migrant population. A specific microplan is being prepared to search and reach these clusters, which pose a great risk to the program especially in high-risk areas. Already the intervention has resulted in good performance during the January round in which around 1 million additional children were immunized by special vaccination teams at bus-stops, railway stations and at fairs.
This year, it is presumed that the proposed intervention of using mOPV1 will work in the field. However we can ill afford to just wait and see the results, rather the situation demands to keep other alternate options in place in the eventuality of not able to achieve expected target during the year. One most essential pre-requisite before using mOPV1 is to first ensure that no Type 3 wild poliovirus is circulating in the community. However finding of a new P3 case in last week of December 2004 has given us some concerns. What could be the other options, then? Targeted use of IPV in focal endemic areas could be one alternative, worth trying. IAP has already recommended to Government of India to give permission for licensing of IPV in India and also to introduce IPV in a phased manner starting from states like Kerala.
Targeted use of IPV in focal endemic areas:
For the first time, WHO has seriously considered IPV as an option in 'pre-eradication phase' in developing countries. This is a major shift in the policy of WHO that till quite recently seen discouraging any large scale use of IPV in poor developing countries for a variety of reasons. Palpably, it reflects the urgency to break the 'deadlock' of persistence of wild virus transmission in focal endemic areas. In a recently concluded meeting of Ad Hoc Advisory Committee on Polio Eradication (AACPE) in Geneva, the committee has urged the WHO to review historical data on use of IPV in 'outbreak response' situations.
Improvement of Routine Immunization:
The current strategy has put almost all the reliance and emphasis on SIAs. It seems the strategists are not having much faith on the effectiveness of routine immunization (RI), and by increasing frequency of SIAs, they have left nothing for the RI. This is indeed a major flaw. Even if transmission is broken and zero polio status is achieved through too closely spaced SIAs, it is ultimately RI that would determine the herd immunity and would thwart any incidence of re-introduction of the disease in the community.
To enthuse new life to moribund state of RI in most of endemic districts, it would not be a bad idea to try a 'combo' of DPT-IPV in these areas for routine coverage. Though there are logistic problems of using IPV apart from financial, availability, immunogenicity issues that may discourage strategist to exercise this intervention, but ultimately we will have to bridge the gap between RI and SIAs, sometimes somewhere. And this is the one exciting option that can be considered seriously.
We need some drastic measures:
The problem of persistence of wild virus transmission in endemic regions of UP and Bihar demands some drastic measures. The measures successful elsewhere may not work here, considering the peculiar environmental, demographic and geopolitical setting of the region especially the western UP. Here, even reaching 90% of population is not seemingly working. We need to take some drastic, harsh, and unconventional measures to break the deadlock otherwise we shall be facing the similar situation next year.
Few such measures are worth considering:
- Devise a strategy where even coverage of less than 90% of target population is able to succeed in providing enough immunity to halt wPV transmission. Use of mOPV should provide the breakthrough.
- Focus more attention to endemic areas and deployment of more number of SMOs/deputy SMOs, social mobilizers, health workers at block level should improve the performance.
- Fixing accountability to village/tehsil/town/block level administration officer may also help.
- Giving responsibility of immunization sessions to village 'pradhans'/chairman and members municipal board/social welfare committee of mohalla/s may also provide improvement.
- Provision of incentives of good work and at the same time certain coercive measures to counter resistance may also work
- Help of paramilitary forces to supervise and monitor immunization sessions may be another option.
- 'Mobile vaccination units' and more easily accessible 'vaccination booths' equipped with all essential antigens to provide RI should be made available.
- Using DPT-IPV combo in RI should provide new impetus to falling coverage of RI.
- More rapid, frequent periodic review and assessment of situation preferably on a bi-monthly basis.
- Willingness and preparedness to introduce a new intervention at a short notice should an old strategy fails. In other words, more resilience on programmatic implementation is needed.
These are few additional measures suggested to incorporate in the ongoing initiative. But major thrust should be on already implemented strategies where we are lacking. Though anticipated interruption of wild polio transmission could not be achieved in 2004 but there is no reason to panic. We must be open to all alternatives but is not time to find faults in strategies. It is time to collaborate our efforts and focus on west UP and Bihar where it is clear there are still gaps in implementation of programme. If we can reach to all children particularly of minority community during coming SIAs there is no reason why interruption of wild virus transmission cannot be achieved in first half of 2005 itself. | | | | Compliance with Ethical Standards | | Funding None | | | | Conflict of Interest None | | |
- www.npspindia.org accessed on 10-3-2005.
- Thacker N, Vashishtha VM. Polio eradication: Current Scenario and End Game Strategies. In: Gupte S (Ed,) Recent Advances In Pediatrics-15, Jaypee Brothers, New Delhi 2005; 244-257. [PubMed]
- Thacker N, Shendurnikar N. Current status of polio eradication:.In: Shendurnikar N, Thacker N (Eds,) Current issues In Pediatrics, Paras Medical Publisher, Hyderabad. 2005; 203-212.
- The Twelfth meeting of the India Expert Advisory group for Polio Eradication. Delhi. 2-3 December 2004. AFP Alert, Vol 8,No.3, 2004.
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| Cite this article as: | | Thacker N, Vashishtha V M, Shah N K. POLIO ERADICATION : HOW FAR IS INDIA TO ERADICATION?. Pediatr Oncall J. 2005;2. |
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