Dr. Sabra Klein is an associate professor of molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health. She is a leading expert on sex and gender differences in immune responses and susceptibility to infection and currently has authored more than 100 peer-reviewed publications, several book chapters, and edited two books on the broad topics of sex differences in response to infection and treatments for infectious diseases. During the 2009 influenza pandemic, she was commissioned by the World Health Organization to evaluate and publish a report on the impact of sex, gender, and pregnancy on the outcome of influenza virus infection. Dr. Klein has been invited to write reviews to introduce journal policies about sex reporting, wrote an op ed in the New York Times about sex-specific dosing of vaccines, and was lead author on an opinion piece in PNAS defining the importance of sex as a biological variable in biomedical science. She is currently president of the Organization for the Study of Sex Differences, principal investigator of the Johns Hopkins Specialized Center for Research Excellence (SCORE) in sex and age differences in immunity to influenza, and co-director of the Johns Hopkins Center for Women’s Health, Sex, and Gender Research.