"When you [put] someone who's infectious with a respiratory illness in a setting where there are other sick people, unless you are able to completely control where the air goes from that [infected] person, you're likely to infect other people who are also sick and more likely to be vulnerable to the virus."

"The fact that MERS has spread around the world is not surprising. The question is, 'Where is it going to spread to next?' "

"I think we're all aware of the fact that we're seeing this in much more real time than we have those [MERS outbreaks] on the Arabian Peninsula."

"Once it gets into an area, it has just not gone away."

"In the Midwest, we've always said our biosecurity efforts were sufficient to deal with [high-path avian flu] … but we've never really been challenged. Obviously, the biosecurity systems we have are not adequate."

"Influenza viruses have been thought in the past to be transmitted by birds to birds in close contact and it was only that kind of transmission we needed to be concerned about. . . . Now we surely have a very dynamic situation in the Midwest . . . where we no longer can assume it's just migratory birds."

"We have no real preparedness, and we're seeing that right now with avian influenza."

"All the old dogma about high-path influenza transmission has just gone out the window. . . . We're in totally uncharted territory."

"It [H5N2 avian flu] could be just acting like any other highly pathogenic virus we see, with wind-driven virus transmission. It just hasn't been stopped by the current level of biosecurity."

"We've only been able to culture viruses for 80 years. But if you look at the sampling that's been done from the 1950s onward, there are more flu viruses in animals than we've seen in the past."

"We have immense challenges before us. . . . I liken it to a swimmer in a calm lake who can cover 12 miles in 6 hours. Put that same swimmer in a river heading upstream against a 4-mph current. . . . After 3 hours he ends up 6 miles downstream from where he started. . . . We are not swimming in a calm lake. "

"We know the circumference of the world hasn't changed. . . . On the other hand, the world is much larger and smaller at the same time. It's larger in terms of population . . . it's smaller in that modern transportation has made oceans, mountain ranges, and international borders irrelevant to the spread of infectious agents."

"We're now stretched so thin with the available resources to even respond to the number of birds that are infected in the poultry industry that I'm not sure we're getting the kind of information we need right now to understand this situation."

"We have a lot of work to do to figure out really what it is that we know and don't know, and be humble enough to accept that we don't know. What motivated people not to get vaccinated, and who are they?"

"There's actually been some recent data showing that the more comprehensive and potentially punitive your efforts are to get people vaccinated, the more people reject and fight it and do whatever they can to get around it."

"International [immunization] programs are so important; it's not just the direct benefits to those countries around the world, but it's an indirect benefit to us . . . There's a vaccine protection halo that we benefit from when we protect those in other countries."

"The global health response system is broken . . . What happens if MERS blows up or there's an Ebola-like event in East Africa? I'm not sure WHO has a plan for that."

"That's like saying you don't want to call the fire department because you're afraid the trucks will create a disturbance."

"The one thing we can do to truly take all of this [the pandemic threat of avian flu strains] off the table is the development of a truly game-changing flu vaccine. We have no machinery set up globally to do that, none."

"There was almost a rush to [assure] the public that we knew a lot more than we did. But we're saying you can't rule out respiratory transmission."