A final attack on Polio

The Union budget for 2007-08 has provided a significant outlay of Rs.1,290 crore for polio eradication and announced a revised immunisation plan, particularly for some districts of Uttar Pradesh and Bihar where the virus persists. This important effort is part of the campaign to eradicate the indigenous wild poliovirus from one of the last four countries where it is found. As the World Health Organisation noted recently, some areas of India, Nigeria, Pakistan, and Afghanistan are polio-endemic; 10 other countries are combating tail-end outbreaks caused by importation of the virus. Finance Minister P. Chidambaram acknowledged in his budget speech that the original national goal of eradicating polio by December 2007 has suffered a setback due to outbreaks in U.P. last year. This realisation has prompted the Centre to take some welcome decisions to strengthen the campaign. Among these is the introduction of monovalent vaccine that has greater efficacy against Type 1 wild poliovirus, supplementing the trivalent oral polio vaccine used in immunisation campaigns against both Type 1 and the less prevalent Type 3 viruses (Type 2 is considered globally eradicated). Another important aspect of the intensified campaign is its integration with the National Rural Health Mission, which will make available critical human resources. The newly trained cadre of Associated Social Health Activists of the NHRM will undertake a door-to-door immunisation effort in the high-risk districts — 20 in U.P. and 10 in Bihar; such programmes with specially trained personnel may prove beneficial in these areas because of the poor state of existing health services.

Regular monitoring by health workers and introduction of a better vaccine for the common Type 1 poliovirus can potentially achieve good results. Yet, there is evidence to show that even where supplementary immunisation campaigns have been carried out intensively in U.P. and Bihar, factors such as population density, prevalence of diarrhoea, and low routine immunisation coverage of children have severely hampered the goal of eradication. It is significant that in these two States, the vaccine has achieved lower efficacy than in other States, although children under five received more doses than those in other parts of the country in 2005. The poor outcomes of the immunisation programme are a result of interference by other viral enteric infections transmitted by diarrhoea. Such findings reinforce the fact that a well-directed campaign against polio will need the support of all flagship programmes on rural housing, urban renewal and sanitation, and not just health intervention.

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Date:07/03/2007 URL: http://www.thehindu.com/2007/03/07/stories/2007030704641000.htm