"The way we work in public health is, we make the best recommendations and decisions based on the bes..." — Tom Frieden

The United States has made remarkable progress in reducing both teen pregnancy and racial and ethnic differences, but the reality is, too many American teens are still having babies.

Pregnant women who are in places where Zika is spreading should do everything they can to avoid mosquito bites. And we, as a society, need to do everything we can to control Zika. That means learning more about it; that means controlling mosquitoes more effectively. That means achieving a vaccine.

Our progress against malaria is impressive. But vigilance remains a critical ingredient to protect the health of all people.

Vaccines and antibiotics have made many infectious diseases a thing of the past; we've come to expect that public health and modern science can conquer all microbes. But nature is a formidable adversary.