WHO Director General Gro Harlem Brundtland today stated that she has asked the WHO Smallpox Advisory Group to review guidelines on smallpox vaccination in light of the current concern that populations might be deliberately infected with the smallpox virus.

During the last few days WHO has received several enquiries about the usefulness of mass vaccination to protect people against the malicious use of specific infectious agents, including smallpox.

Smallpox was eradicated almost 25 years ago by a WHO-led programme. Since then there have been no naturally occurring cases and one known laboratory accident. National vaccination programmes against smallpox have been stopped in all countries since the early 1980s.

Current WHO guidelines, updated in 1998, recognise the effectiveness of existing smallpox vaccines. They also detail the incidence of adverse side effects due to vaccination, particularly among people whose immune systems are compromised.

The guidelines recommend that only individuals at risk of exposure (for example, laboratory researchers working on smallpox or human monkeypox) should be vaccinated.

Dr Brundtland has asked the Advisory Group to consider whether WHO should modify this guidance to take account of any potential situation in which the smallpox virus is deliberately used to cause infection.

Any new WHO guidance will immediately be made available to Ministers of Health of the Member States of WHO.