As the use of anthrax vaccine in members of the armed forces has increased, so have anxieties over its safety. A large case-control study of US military staff gives some reassurance: the risk of optic neuritis did not increase in 18 weeks after vaccination. The study also exonerated smallpox, hepatitis B, and influenza vaccines (Archives of Neurology 2006;63: 871-5).

A nationwide study of adverse outcomes in acute hospitals in Belgium confirms what we already know about hospitals being dangerous places for patients (International Journal for Quality in Health Care 2006;18: 211-9). Adverse outcomes affected more than 6% of people discharged. More interestingly though, even after adjusting for case mix, were the striking variations between hospitals. This shows the potential for improvement, the authors argue.

Most of us carry herpes simplex virus 1. It lies latent in the trigeminal ganglia until, reactivated by some sort of stress, it ambushes us with a cold sore. Only one viral gene is expressed during the latency phase, and no viral particles are produced. The product of that gene has now been identified (Nature 2006;442: 82-5). It's a microRNA that protects the infected neurones from cell death, allowing the infection to persist. Mammalian …