Funding for this research was provided by:
Wellcome Trust (204419)
Received: 20 June 2019
Accepted: 18 October 2019
First Online: 28 November 2019
Ethics approval and consent to participate
: This study was approved by the University College London Research Ethics Committee (5683/002). The HSE obtained informed written consent for blood samples to be collected and stored for future analyses. We were given permission to access the data by the Health Survey for England.
: Not applicable
: GT reports personal fees from Genocea Biosciences, outside the submitted work. CJ is an Associate Editor at BMC Public Health. All other authors have no competing interests.