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) Subgroup analysis results based on publication year. (B) Subgroup analysis results based on specimen sources. (C) Subgroup analysis results based on testing methods.
