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.
Martin-Gallardo A, Fien KA, Hu BT, Farley JF, Seid R, Collins PL, Hildreth SW, Paradiso PR.Martin-Gallardo A, et al. Among authors: collins pl.Virology. 1991 Sep;184(1):428-32. doi: 10.1016/0042-6822(91)90863-7.Virology. 1991.PMID: 1714666
Collins PL, Hill MG, Johnson PR.Collins PL, et al.J Gen Virol. 1990 Dec;71 ( Pt 12):3015-20. doi: 10.1099/0022-1317-71-12-3015.J Gen Virol. 1990.PMID: 2273393