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.
Lansley M, Bedford H.Lansley M, et al. Among authors: bedford h.Vaccine. 2003 Jun 20;21(21-22):2877-81. doi: 10.1016/s0264-410x(03)00160-9.Vaccine. 2003.PMID: 12798630