. Author manuscript; available in PMC: 2020 Nov 5.
Published in final edited form as: Epidemics. 2018 Jul 9;26:1–8. doi: 10.1016/j.epidem.2018.07.001
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).