LONDON, April 12, 2007--The costs of eradicating poliomyelitis from the remaining infected countries, while high in the short term, are much lower than the long term costs of trying to control infections without eradication. And a recently developed monovalent vaccine is almost three times more effective against type 1 poliomyelitis than an existing trivalent vaccine. These are the findings of two Articles published Online and in an upcoming issue of The Lancet.

Both Articles look at the success of the Global Polio Eradication Initiative (GPEI), started in 1988 by the World Health Organisation, which has reduced the global incidence of poliomyelitis by 99%.

In the first, Professor Kimberly Thompson and Dr Radboud Duintjer Tebbens of Harvard School of Public Health, Boston, USA used a dynamic modelling technique based on current wild poliovirus endemic areas of India. The results show the importance of maintaining and increasing the immunisation intensity to complete eradication.

They find that even small decreases in this intensity could lead to large outbreaks—and state that more short term funds are needed than are currently being spent.

The authors conclude: "Worldwide eradication of polioviruses is likely to yield substantial health and financial benefits, provided we finish the job."

In the second paper, Dr Nicholas Grassly and of the Department of Infectious Disease Epidemiology, Imperial College, London, UK and Dr Bruce Aylward, of the World Health Organisation, Switzerland and colleagues did a study of the efficacy of the monovalent oral type 1 poliovirus vaccine (moPV1).

This vaccine was developed in 2005 to tackle persistent poliovirus transmission in the last remaining infected countries—India, Pakistan, Afghanistan, Nigeria, Niger, and Egypt.