Figure 8.
Weekly National Influenza Isolation Rates in 2009. *Note: The time period between the two dashed lines was August 2009.
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.