Bromet says the study findings can help countries identify their own high-risk populations, whether it's older adults in Ukraine or young divorced women in Japan.

CNN: People in affluent nations may be more depression-prone

Kasai noted that one of the ways that H1N1 differs from seasonal flu and other pandemics is that it seems to affect young adults more severely, in addition to traditionally high-risk populations like children and the elderly.

FORBES: Healthcare

The specific drug tested in the trial -- Idelalisib -- was shown in a first phase of study to be safe in high-risk populations, and to help reduce the size of affected lymph nodes for long periods of time.

CNN: A workout a day may keep cancer away

By 2014, our goal is to halve malaria illnesses and deaths in 70 percent of at-risk populations, by accelerating and intensifying malaria control efforts in the high burden countries of sub-Saharan Africa.

WHITEHOUSE: Our Top Stories

Recognizing that terrorists are willing to manipulate societal norms to evade detection, TSA has been actively assessing less invasive screening methods for low-risk populations, such as younger passengers, while still maintaining a high level of security.

FORBES: TSA Reconsiders Invasive Patdowns of Children