The Fundamentals of Investigating an Outbreak

Arjun Srinivasan, MD, associate director, Healthcare-associated Infection Prevention Programs, Centers for Disease Control and Prevention, discusses the “steps” associated with investigating an outbreak.

Interview Transcript (slightly modified for readability)

“Outbreak investigations have lots of steps. We think of them as steps, but they don’t really unfold as [finishing] a step and [moving] on to the next step. What I like to tell people is that, we talk about outbreaks in steps, but we conduct outbreaks as series of things that we need to do. Some of the important things that we need to do when we investigate outbreaks is, of course, understand what we’re investigating. We need to have a good definition of what the outbreak is and what the cases are, and then we need to begin exploring the factors that are associated with the cases. We call that a line list; we look at the charts, we go and talk to people, to try to understand the factors that all of these patients seem to have in common.

The third big part of outbreak investigations is going into the areas (the unit, the operating room) where the outbreak is occurring and watching practices and trying to figure out what might be leading to the outbreak, what’s leading to the transmission of organisms.

So, those are the three fundamental steps of an investigation. The key thing to remember is that, oftentimes, they’re all happening at the same time, so, you’re doing them all simultaneously, even though we tend to talk about them as if they happen sequentially.”