Timely production of A/Fujian-like influenza vaccine matching the 2003–2004 epidemic strain may have been possible using Madin–Darby canine kidney cells

Timely production and antigenic match with those of the epidemic strains are required for influenza vaccines. A/Fujian/411/2002-like (H3N2) virus was the main epidemic influenza virus during the 2003/2004 season in the northern hemisphere. But A/Fujian-like reassortant viruses were not available until more than one year later. We evaluated the A/Kumamoto/102/2002 strain, an A/Fujian/411/2002-like strain isolated in 2002, as a potential vaccine. We compared A/Kumamoto/102/2002 viruses isolated from the same clinical sample in Madin–Darby canine kidney (MDCK) cells and eggs. Kumamoto/102/2002 isolated from eggs grew poorly and showed amino acid mutations of haemagglutinin. In contrast, A/Kumamoto/102/2002 isolated from MDCK cells grew well in MDCK suspension culture. The amino acid sequence of MDCK-derived A/Kumamoto virus was identical to that of A/Fujian/411/2002. These results suggest that culture in MDCK cells could have produced an influenza vaccine with a better antigenetic match to the predicted epidemic strain for the 2003/2004 season than the vaccine actually produced.