Vaccine trial may herald the elimination of polio

17 Oct 2008

Paul Chinnock

Source: BBC (see original article)

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Nigeria now accounts for the majority of the world’s remaining polio cases but a successful trial of a new vaccine has given new hope that this infectious disease could soon be eliminated as a public health problem.

Four countries – Afghanistan, India, Pakistan and Nigeria – have yet to eliminate polio. The poorest people in these countries are particularly at risk. Eighty-five per cent of cases reported this year have been in Nigeria.

A trial in Nigeria compared a new monovalent vaccine (one dose required) with the trivalent polio vaccine. After analysing the vaccination histories of 21,815 children with acute flaccid paralysis, 14% of whom had polio, collected between January 2001 and December 2007, researchers concluded that the new vaccine was four times more effective in protecting children. One dose of the monovalent vaccine gave a child a 67% chance of being protected, compared with a 16% chance after receiving the standard trivalent vaccine.

The researchers – from Imperial College, UK – argue that the vaccine could now eliminate type 1 polio – the most common form of the disease – in Nigeria, providing it reaches enough children.

A vaccine that only requires one dose and is more effective will greatly aid in the task of eliminating the disease but there are other barriers to be overcome. Particularly in the northwest of the country, there has been strong opposition to vaccination programmes from religious and other groups. The Nigerian government has set up a presidential taskforce to identify barriers to immunisation, and potential solutions.

The research was published in the New England Journal of Medicine. The journal, although not open access, has made the text of this research article freely available online.