JIM LEHRER: Now two takes on the U.S. government's response, its investigation, and the many questions surrounding the outbreak. Ray Suarez continues our coverage.
RAY SUAREZ: We get the latest now from two key government officials, first, Secretary of Homeland Security Janet Napolitano.
Secretary Napolitano, what's the U.S. government telling American citizens about traveling to Mexico?
JANET NAPOLITANO, secretary of Homeland Security: Well, both the CDC and the State Department have now issued travelers' advisories or alerts for Mexico, meaning they should avoid all nonessential travel.
RAY SUAREZ: What's changed in the last day for the United States to raise its level of warning?
JANET NAPOLITANO: Basically the amount of knowledge that we have. As I said yesterday at my first press conference on this topic, this is going to be a changing dynamic, and there will be different announcements every day. We want to keep people informed.
But as we've identified more cases in Mexico, identified and pinned down that they are swine flu, those factors led to the decision to go ahead and issue the travelers' advisory.
RAY SUAREZ: What level of scrutiny is being given to people of any nationality coming to the United States from Mexico?
JANET NAPOLITANO: We're doing what's called passive surveillance. Basically, it's looking at people to see whether they appear sick, asking them if they're sick, checking their travel history, see where they've been.
If they are sick, we move them into a separate room, where a public health official can come in and take a look at them, and then make a decision about whether they can come into the country and go get health care or whether, indeed, they need to be returned.
RAY SUAREZ: Are they equipped at an airport or a land crossing to check, do a test whether a person actually has the flu?
JANET NAPOLITANO: That equipment has been moved to the land ports. At our airports, they have that equipment, as well. We also have, at 19 of our airports, we actually have quarantine facilities. Those 19 facilities cover about 85 percent of air passengers.
So, yes, and that's part of the preparation that we've been doing. Right now, you know, a lot of cases, but a manageable number of cases, but we don't know if that's going to increase exponentially over the next few days. So our planning has all taken into account different types of scenarios.
RAY SUAREZ: You've also made a public health emergency declaration. As a triggering event, what happens once you pronounce one?
JANET NAPOLITANO: Well, I announced that the Department of Health and Human Services was making an emergency declaration. That does several things.
One is, it frees up resources that we can use to preposition antivirals to make antivirals available out of the stockpile, to move other equipment. It also allows for the issuance of an emergency health authorization, which is something that's done with the FDA, so that a drug like Tamiflu could be used even for a child under the age of one.
RAY SUAREZ: Has the United States government been stockpiling Tamiflu?
JANET NAPOLITANO: Yes. We have 50 million courses of Tamiflu and Relenza, which are two antivirals that have shown that they have some efficacy against this strain of swine flu.
RAY SUAREZ: How do you get it out to various places in the country?
JANET NAPOLITANO: There's a whole network that does this, through basically public health departments. And we've been in daily touch with the public health network, also state homeland security advisors. And so we actually have a very, very robust system for how that happens.
RAY SUAREZ: And how long does that take?
JANET NAPOLITANO: It goes very, very fast. And so the information I have is some of that stockpile is moved even as soon as today.
RAY SUAREZ: Secretary of Homeland Security Janet Napolitano, thanks for joining us.
JANET NAPOLITANO: Thank you.