Received: 23 February 2019
Accepted: 28 October 2019
First Online: 7 November 2019
Ethics approval and consent to participate
: The company ethics approval process (Global Ethics and Compliance) determined this project to be exempt from human subject research oversight and consent and data access approval was not required. The study used existing data, originally collected and anonymized by third parties, and analysed on an aggregate level.
: Not applicable.
: The authors either currently or have previously been employed by the company GlaxoSmithKline (GSK).