About the Authors

Ann Levin

Affiliation Independent consultant to WHO, Washington D.C., United States of America

Susan A. Wang

Affiliation Department of Immunization, Vaccines and Biologicals, World Health Organization, Geneva, Switzerland

Carol Levin

Affiliation University of Washington, Seattle, Washington, United States of America

Vivien Tsu

Affiliation PATH, Seattle, Washington, United States of America

Raymond Hutubessy

hutubessyr@who.int

Affiliation Department of Immunization, Vaccines and Biologicals, World Health Organization, Geneva, Switzerland

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: AL SAW CL. Analyzed the data: AL CL. Contributed reagents/materials/analysis tools: SAW VT RH. Wrote the paper: AL.