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.
Predicted probability using logistic regression models of serconversion (four-fold rise in hemagglutination inhibition titer) for each vaccine strain. Modeling controlled for gender, age, body mass index, and modified Vulnerable Elders Survey score.
