Vol. 208, No. 1, January 17, 2011. Pages 181–193.

The reference for Steel et al. was listed incorrectly in the reference list. This has been corrected in the html and pdf versions of the article. The correct reference is as follows:

Steel, J., A.C. Lowen, T. Wang, M. Yondola, Q. Gao, A. García-Sastre, and P. Palese. 2010. Influenza virus vaccine based on the conserved hemagglutinin stalk domain. MBio. 1:e00018–10.