The World Health Organization (WHO) has developed a new mechanism, described in this week's PLoS Medicine, for issuing urgent guidelines to health professionals in a public health emergency such as an infectious disease outbreak. The first rapidly issued guideline was developed by the WHO in order to advise countries that were dealing with avian influenza A (H5N1) infection. Typically, the most rigorous clinical practice guidelines take two years or more to develop. The laborious process involves convening experts who search for and appraise all the relevant research literature, and who meet several times before making treatment recommendations. Such a time frame is clearly not practical in an emergency situation. Holger J. Schünemann and colleagues, authors of the rapidly issued guideline on H5N1 infection, say that it took just one month to convene an expert team, and only five weeks for the team to summarize the evidence and prepare draft guidelines. The guidelines were then discussed at a two-day meeting, after which a draft manuscript for publication was prepared within 10 days. In a related editorial discussing how WHO is responding to global public health threats, the PLoS Medicine editors comment that while the time scale for developing the H5N1 guideline was "miraculously quick in WHO terms", an even quicker time frame is sometimes going to be needed. Citation: Schünemann HJ, Hill SR, Kakad M, Vist GE, Bellamy R, et al. (2007) Transparent development of the WHO Rapid Advice Guidelines. PLoS Med 4(5): e119.