JUDY WOODRUFF: No doubt about it, we're in the middle of flu season, and this one is shaping up to be a particularly tough slog, possibly the worst since 2008.

The Centers for Disease Control report that flu activity is widespread in 46 states. In fact, the only places where flu activity was limited to local pockets were Arizona, California, Alaska, Hawaii, and here in Washington, D.C.

CDC Director Dr. Thomas Frieden is here to discuss that, as well as what he thinks people should do, and why some in the field are questioning some of those recommendations.

Dr. Tom Frieden, welcome back to the program.

DR. THOMAS FRIEDEN, Centers for Disease Control and Prevention: Thanks for having me.

JUDY WOODRUFF: Just how serious — much more serious is the flu this year?

DR. THOMAS FRIEDEN: This year, it's what's called an H3 year, one particular strain of flu that tends to be worse than other strains of flu, years with this strain predominance, more people hospitalized and, sadly, more people who will die from influenza.

Furthermore, in this year, the match between the vaccine and the virus is not good. So we don't expect the vaccine to work as well as it does in most years.

JUDY WOODRUFF: So you're saying it's not a perfect match. You're also urging people to go ahead and get that vaccine. That doesn't make sense to some people.

DR. THOMAS FRIEDEN: Based on past trends, at least nine out of 10 people who are going to get a flu vaccine have already got one. And even if it's not effective against the most predominant strain, it is still effective against the strains that are still out there. So it has some level of protection.

I got the flu shot. My family got the flu shot. But, at this point, we're making a very important recommendation for people who get the flu. And that's to think about getting treatment for flu with antiviral medications, such as Tamiflu or Relenza.

JUDY WOODRUFF: So, what does that mean? If someone who is watching this thinks they may be coming down with the flu, what should they do?

DR. THOMAS FRIEDEN: Well, first off, the question is, how high is the risk between being really sick and how sick is the person? So if someone is really sick in the hospital, they need to get antiviral medications.

If someone is over 65, under the age of 2, or has a chronic health problem, like diabetes, asthma, heart disease, then it's really important at the first signs of flu to talk to your doctor or nurse practitioner or physician assistant about getting a prescription for Tamiflu because — or Relenza — because, the sooner you take it, the more you benefit from it.

JUDY WOODRUFF: And it sounds like you're saying people should check in with their doctor regardless.

DR. THOMAS FRIEDEN: Absolutely. It's a good idea to be in touch with your doctor. Anyone with flu can benefit from antiviral medications.

They're not the miracle drugs that some of our antibiotics are, but the CDC scientists that have looked very carefully at this have concluded that, though they're not perfect, they do cut down the duration and severity of the illness. They can keep you out of the hospital. If you're hospitalized, they might keep you out of the intensive care unit, and they might be able to save your life.

JUDY WOODRUFF: Now, you say that, but I know you are aware that there are other infectious disease experts out there in this country right now saying that the results are really mixed on these antivirals, like Tamiflu.

And, in fact, there is a group of British researchers, a report was just issued in the last couple of days, who say their study shows emphatically that they don't do the good that some believe they do. And they say they even have some bad side effects.

DR. THOMAS FRIEDEN: We have not seen severe side effects. We have seen consistent modest benefit with the medication.

It's not a miracle cure. It doesn't make you get out of bed and dance the next moment after you take it. But if you look at the weight of evidence, especially for people who have underlying conditions, and especially if they take it in the first 48 hours after the disease starts, then the evidence suggests that it will help you get better.

JUDY WOODRUFF: Now, Dr. Friedman, I also want to ask you about Ebola. You have just come back from West Africa.

We know there's been progress in some places, Liberia. But we also know that Sierra Leone — and you had talked about this — the number of cases continue to increase, particularly in the rural countryside. What did you see when you were there?

DR. THOMAS FRIEDEN: From the first time I went during this epidemic in September — August and September to now, it's really a night-to-day difference.

The response is dramatically better. We have made tremendous progress, but we have a long way to go. We're nowhere near out of the woods. In each of the three countries, there are unique challenges. And in each of the three countries, there has been real progress.

But Guinea shows the risk of complacency. They had a decrease before, and then it came back up. So, Liberia needs to learn from that. Sierra Leone still has a lot of cases, but they're implementing effective programs that should bring those cases down. We have to get to zero. That's the critical challenge in this epidemic.

JUDY WOODRUFF: And just one other question. There was a report today that a federal lab technician who was possibly exposed to Ebola here in this country — turns out he or she is not sick.

But that does raise the question. There have been some other incidents with dangerous viruses, bacteria that were not adequately protected in a CDC lab. Are you confident right now that adequate precautions are being taken in your facilities?

DR. THOMAS FRIEDEN: I am very concerned about any potential exposure.

And we want the laboratory staff to report if they have any concern of an exposure or a problem. What we will do in this case, as we have in the others, is look very carefully. Could this have been prevented? If so, we will put in the systems to prevent it, not only in this individual lab, but in other labs as well.

We take the safety and security of our own staff very seriously. In this incident, there was a possible exposure to that one laboratory technician, not to anyone else at CDC, no other exposure. But working with dangerous pathogens — and this laboratory has done more than 10,000 tests for Ebola since the outbreak started, but we always have to take great care to make sure that we do it safely.

JUDY WOODRUFF: Well, we're certainly glad that technician is not sick.

Dr. Tom Frieden with the CDC, we thank you.

DR. THOMAS FRIEDEN: Thank you.