US researchers are warning people vaccinated against smallpox as children that they are unlikely to still be protected. Smallpox was eradicated in the mid-1970s, but researchers warn bioterrorism fears mean mass vaccination should now be reconsidered. But experts are divided over whether research, featured in New Scientist magazine, mean there should be a renewed mass smallpox vaccination programme. In tests, doctors from Maryland found only 6% of over 600 microbiologists who were being re-vaccinated in the late 1990s were still immune to smallpox from their earlier vaccinations. One in a million recipients is likely to die Dr David Brown, PHLS...