Safe landing for global polio eradication: a perspective.

After over two decades of immense efforts, the global polio eradication initiative may be approaching its final phase. With leadership from WHO, great efforts of national programs and support from its collaborators, combined with the recent use of mono and bivalent oral polio vaccines, success may be at hand. For a "safe landing" of this global program, it is important once more to recall the key role of routine vaccination as the foundation on which mass vaccination campaigns can be successful. Continued effective routine vaccination programs are essential to reduce the ill effects of high population density in formerly endemic countries. Considering the large number of subclinical poliovirus infections, failing to reduce the number of unvaccinated persons per km(2) could severely impact the final stage of eradication. Here the authors, from their personal perspectives, discuss how the current program will be viewed from 2012 onwards. The authors will highlight the epidemiological importance of circulating vaccine-derived poliovirus, the problem of biosecurity as well as the use of inactivated polio vaccine and how each of these may affect the post eradication era and how research into each of these must continue to ensure success.