1. Planned Parenthood of Arkansas and Eastern Oklahoma, Inc., 5780 S. Peoria Ave, Tulsa, OK 74105, USA
2. Department of Medicine, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
3. Division of Infections Diseases, University of North Carolina, Chapel Hill, NC 27599, USA
4. GlaxoSmithKline, Research Triangle Park, NC 27709, USA