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) HI titer on day of re-challenge and peak infectious virus titer in tracheal secretions after re-challenge. B) Fold change in HI titer from the day of re-challenge to 14 days later and peak infectious virus titer in tracheal secretions after re-challenge.
