Characteristics of epidemiological strains of influenza A virus (H3N2) isolate in 1997-1999. Virus A/Moscow/10/99--a candidate to become the vaccine strain

Antigenic properties of influenza A(H3N2) viruses isolated during two epidemic seasons 1997-98 and 1998-99 in Russia are analyzed. All strains are antigenic variants of the reference strain A/Sydney/5/97. Characteristics of epidemic strain A/Moscow/10/99, proposed by WHO expert committee as vaccine strain for 1999-2000 have been studied. This strain, isolated on chick embryos, is characterized by high reproductive activity in chicken embryos with an infectious titer of 10(6) EID50/0.2 ml, easily adapts to MDCK culture, and has a thermostable hemagglutinin.