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.
A funding organization was incorrectly omitted from the Funding Statement. The Funding Statement should read: "Funding support by the Bill and Melinda Gates Foundation (Disease Control Priorities 3 project). The employers of the authors had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."
Competing Interests: No competing interests declared.
