Footnotes

• Contributors All persons designated as authors qualify for authorship and participated sufficiently in the work to take public responsibility for appropriate portions of the content. JAS designed the study, analysed data, drafted the initial manuscript and approved the final manuscript as submitted. DCB contributed to the discussion, revised the manuscript and approved the final manuscript as submitted. JO conceived of the study, synthesised data, revised the manuscript and approved the final manuscript as submitted.

• Funding This work was supported by full-time salaries at the Department of Health of the State of New York.

• Competing interests None declared.

• Provenance and peer review Not commissioned; internally peer reviewed.