Fig. 1.
Influenza positivity from 2010 to 2016. The figure shows the positivity observed and the influenza subtypes identified during the study period.
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.