Figure 1.
Hypothetical randomized controlled trials illustrating approaches to estimated waning of influenza vaccine effectiveness. Abbreviation: RCT, randomized controlled trial; RR, relative risk; VE, vaccine effectiveness.
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.