An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Nelson S, Summer WR.Nelson S, et al. Among authors: summer wr.Infect Dis Clin North Am. 1998 Sep;12(3):555-67, vii. doi: 10.1016/s0891-5520(05)70198-7.Infect Dis Clin North Am. 1998.PMID: 9779378Review.