Addendum: Kong, M.Y.; Whitley, R.J.; Peng, N.; Oster, R.; Schoeb, T.R.; Sullender, W.; Ambalavanan, N.; Clancy, J.P.; Gaggar, A.; Blalock J.E. Matrix Metalloproteinase-9 Mediates RSV Infection in Vitro and in Vivo. Viruses 2015, 30, 7, 4230–4253