. Author manuscript; available in PMC: 2018 Nov 16.
Published in final edited form as: Lancet. 2018 Nov 8;392(10159):1736–1788. doi: 10.1016/S0140-6736(18)32203-7
This is an Open Access article under the CC BY 4.0 license (http://creativecommons.org/licenses/by/4.0/).