For more on the flu, go to www.cdc.gov/flu/

It’s been some time since Nancy Cox has had the flu — she gets a yearly flu shot, eats well and steers clear of sick people — but she still spends most of her days obsessing about it. Cox is director of the Influenza Division at the Centers for Disease Control and Prevention and director of the World Health Organization Collaborating Center for Influenza. When she retires on Nov. 29, Cox will have spent almost four decades working to keep people around the world from contracting flu bugs.

It isn’t boring work.

“What makes influenza so interesting and challenging is we can’t predict what is going to come next,” she says.

Despite her many accolades — Cox was even named Time Magazine’s “The Time 100: People Who Shape Our World” — she is most proud of the team she has built at the CDC, which has grown from a staff of 16 to more than 300 today.

“I have hired a lot of younger, talented individuals,” she says. “I want them to have an opportunity to lead.”

Q: We talk about the flu as if it were one thing. What is it exactly?

A: Influenza is a disease caused by a complex set of viruses. They can cause a mild respiratory infection or severe disease with hospitalization and, in some cases, even death. It is estimated that about 200,000 people are hospitalized as a result of influenza infections each year.

Q: What do we know about the flu?

A: We have seasonal viruses that are well-adapted to humans and circulate in the winter months in the U.S. Those seasonal viruses can change unpredictably. We have to keep monitoring them year around in order to stay ahead of the game with updating the vaccine components.

Q: Can you talk about your work with the World Health Organization?

A: The CDC has a WHO designated lab that receives flu viruses from countries all over the world. In addition, four other laboratories in other parts of the world are also receiving and testing viruses and developing vaccines. It is always a race against time since we are tracking moving targets, the flu viruses themselves, which change over time. But we have been successful in most years at having well-matched vaccines for the circulating viruses.

Q: Does international travel create a transcontinental exchange of bugs?

A: Absolutely. There is movement of people but there is also movement of animals. There are flu viruses in birds and swine that have exhibited the ability to jump into humans.

Q: Can you talk about prevention efforts?

A: Our efforts in the U.S. are better than they used to be but not where they should be. In this country, we recommend that everyone get an annual flu shot, but vaccine uptake is still too low. We also have antiviral medications that are effective for treating people who have influenza but clinicians are often unaware of these. We need to continue to work on improving vaccine coverage and to educate clinicians about the benefits of using antivirals for certain patients.

Q: How did you become interested in the flu?

A: I began working on influenza while doing research for my Ph.D. I stayed with influenza because it is such a fascinating disease to study and you learn lots of interesting things every year.

Q: Is the flu always going to be with us?

A: There is ongoing work to try to find successful approaches to developing universal flu vaccines. That is a huge, huge scientific and technical challenge. Maybe some very clever person will be able to design a vaccine that solves all of our problems with influenza, but I am not going to hold my breath.