On 20 October 2000, Evans/Medeva Oral Polio Vaccine (OPV), which to the knowledge of the World Health Organization has only been used in the United Kingdom and the Republic of Ireland, was recalled in the UK. This vaccine has never been used in the immunization campaigns that are ongoing as part of the Global Polio Eradication Initiative.

The recall was prompted by evidence that the Evans/Medeva vaccine was manufactured in contravention of European Union guidelines, and was not based on any adverse events related to the vaccine. The specific concern is that fetal bovine calf serum (FCS) from the UK was used in the manufacture of the Evans/Medeva vaccine, at a time when there was a risk of Bovine Spongiform Encephalopathy (BSE) in that country. WHO endorses the recall step as a precaution, even though FCS is removed in the manufacturing process of the vaccine and there is no evidence that FCS could transmit BSE. In view of this breach of EU guidelines and acting on a precautionary basis, the Health Departments in the UK have withdrawn remaining shelf stocks of the Evans/Medeva brand of polio vaccine, which had already ceased production.

The World Health Organization imposes strict production and quality controls to ensure the safety and efficacy of OPV. WHO recommends that manufacturers use the safest source of materials from countries that have not reported indigenous BSE cases and have a compulsory BSE notification system, compulsory clinical and laboratory verification of suspected cases and a surveillance programme. The Global Polio Eradication Initiative only distributes vaccine supplied by vaccine manufacturers who follow National Control Authorities’ criteria provided by WHO.

OPV is safe and effective and the recommended vaccine for the global effort to eradicate polio by 2005. It is the only vaccine proven to stop transmission of the virus in developing countries. Using this vaccine, the global campaign to eradicate polio has achieved a more than 95% decrease in the number of polio cases worldwide in the twelve years since it was launched, and is on track to eradicate polio.