Letter to the Editor

Affiliations

• ¹ FDA Office of Vaccines Research and Review, Silver Spring, MD, USA.
• ² University of California School of Medicine, San Francisco, CA, USA.
• ³ BANDIM Project, Copenhagen, Denmark.
• ⁴ University of Southern Denmark, Odense, Denmark.
• ⁵ Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, USA.