About the Authors

Helen Fox

Affiliation Division of Virology, National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom

Sarah Knowlson

Affiliation Division of Virology, National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom

Philip D. Minor

Affiliation Division of Virology, National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom

Andrew J. Macadam

Andrew.Macadam@nibsc.org

Affiliation Division of Virology, National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceptualization: AJM. Formal analysis: HF SK AJM. Funding acquisition: AJM. Investigation: HF SK. Methodology: HF SK AJM. Project administration: AJM. Supervision: AJM. Visualization: AJM. Writing – original draft: PDM AJM. Writing – review & editing: PDM AJM.