Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Scenario 1 is in blue (with squares), scenario 2 in red (with circles) and scenario 3 in green (with triangles). See Figure 1 and Appendix S1 for details about the different scenarios and interventions.
