Physicians who see patients outside of hospital systems, such as those working in private offices, contribute disproportionately to the spread of antibiotic resistance because they are more likely to prescribe drugs unnecessarily, a first-of-its-kind nationwide study that looked at patterns of antibiotic use and drug-resistant infections has found.

In the world of public health, no scenario involving infectious disease is too far-fetched. How often can scientists predict what virus is going to emerge and survive long enough to take hold around the world? How rapidly can governments gear up and prepare to deal with a pandemic? And should we worry about such things at all, or is the era of fast-spreading infectious diseases behind us?

Can vaccines be more useful for some people than for others?