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.
van Es JH, Gmelig Meyling FH, van de Akker WR, Aanstoot H, Derksen RH, Logtenberg T.van Es JH, et al.J Exp Med. 1991 Feb 1;173(2):461-70. doi: 10.1084/jem.173.2.461.J Exp Med. 1991.PMID: 1899104Free PMC article.