GENEVA, 26 OCTOBER - Following the review of guidance on smallpox vaccination I announced last week, WHO has consulted with our advisory committee and has updated the official guidance.

The conclusion of the review states that:

"Existing vaccines have proven efficacy but also have a high incidence of adverse side-effects. The risk of adverse events is sufficiently high that mass vaccination is not warranted if there is no or little real risk of exposure. Individual countries that have reason to believe that their people face an increased risk of smallpox because of deliberate use of the virus are considering options for increasing their access to vaccines. The vaccines would be given to people who are at risk of exposure to smallpox, including health and civil workers, and would be used in a search and containment exercise should an outbreak occur."

In summary, the guidance is that vaccination of entire populations is not recommended. The reason for not recommending such mass vaccination is that there is a risk of severe reactions to the vaccine, including death, and the fact that vaccination can prevent smallpox even after exposure to the virus.

Up to now the guidance has also stated that only those with suspected exposure to smallpox or a related virus should be vaccinated. That has not changed.

What has changed is the increasing attention being given to the extent and quality of existing vaccine stocks, and to the possible need both to stimulate vaccine production and increase stocks of vaccine for use in the event of an outbreak.

WHO confirms that the best method of stopping a smallpox outbreak, should it occur, remains the same – search and containment. That means identifying persons with smallpox, identifying those people who have been in contact with them, and vaccinating them.

People who have been vaccinated in the past are unlikely to develop the most serious effects of smallpox.

This advice and background information on smallpox is now being made available to governments through the WHO website. Along with this advice we are providing Frequently asked Questions and Answers about smallpox and a smallpox Fact Sheet with an electronic slide set of training materials on smallpox. Other information that will be provided to Health Ministers on request includes a list of vaccine manufacturers that have the potential to produce smallpox vaccine and the names of laboratories that can diagnose smallpox. WHO has also re-established a team of technical experts in smallpox who are available to assist countries in the investigation and response to outbreaks.

Finally, I want to emphasize that should an outbreak of smallpox be detected in any country, this should be considered an international emergency. WHO will help countries to pool available resources so as to contain the disease as rapidly and effectively as possible.