UN health experts have recommended cutting the standard dose of yellow fever vaccine by 80% in emergencies, amid a global vaccine shortage. A smaller dose would provide immunity for at least 12 months, they said. Emergency stocks have been depleted by a mass immunisation programme in Angola, where the disease has killed more than 300 people since December. A surge of cases in the Democratic Republic of Congo has raised fears of a crisis situation. The current outbreak of the disease has seen 18 million vaccine doses distributed in Angola, DR Congo and Uganda. In a statement, the World Health Organization (WHO) cautioned that so-called “fractional dosing” would only be used as a short-term measure in emergency situations where a shortage exists.