ACE inhibitors can weaken the immune system’s ability to fight off serious bacterial infections, according to a new study in mice and a small group of people.

Evolutionary changes in viruses reveal why seasonal flu vaccines don’t protect against the 2009 H1N1 flu and provide insight into why older people have immunity to the pandemic virus, two new studies in Science Translational Medicine and Science report.

An easy-to-manage, intermittent dosing schedule of antiretroviral medication may work just as well as daily doses to prevent transmission of human immunodeficiency virus or HIV, new research on monkeys published in Science Translational Medicine suggests. HIV currently affects about 33 million people worldwide, according to the World Health Organization.