An influenza virus inhibitor that acts late in the replication cycle

An inhibitor which is active against influenza A virus was found in Neuramide, a complex tissue extract that is used as an anti-herpes zoster virus treatment. Kinetic studies showed that significant inhibition of virus production occurred when the inhibitor was added to infected cultures up to 5 h after virus penetration. Molecular sieving fractionation showed that the antiviral activity was contained in a low-molecular-weight fraction (molecular weight, less than 1,000).