New Strategies for the Elimination of Polio from India

Nicholas C. Grassly,1* Christophe Fraser,1 Jay Wenger,2 Jagadish M. Deshpande,3 Roland W. Sutter,4 David L. Heymann,4 R. Bruce Aylward4
The feasibility of global polio eradication is being questioned as a result of continued transmission in a few localities that act as sources for outbreaks elsewhere. Perhaps the greatest challenge is in India, where transmission has persisted in Uttar Pradesh and Bihar despite high coverage with multiple doses of vaccine. We estimate key parameters governing the seasonal epidemics in these areas and show that high population density and poor sanitation cause persistence by not only facilitating transmission of poliovirus but also severely compromising the efficacy of the trivalent vaccine. We analyze strategies to counteract this and show that switching to monovalent vaccine may finally interrupt virus transmission.

1 Department of Infectious Disease Epidemiology, Imperial College London, Norfolk Place, London, UK.
2 National Polio Surveillance Project, World Health Organization, New Delhi, India.
3 Enterovirus Research Centre, Parel, Mumbai, India.
4 Global Polio Eradication Initiative, World Health Organization, Geneva, Switzerland.

* To whom correspondence should be addressed. E-mail: n.grassly@imperial.ac.uk