Seasonal flu is a common infectious disease of the respiratory tract caused by influenza virus. There are four types of influenza virus, influenza type A, B, C, and D. The A and B types are of most interest to the medical community because they are the culprits for seasonal epidemics. Occasionally, influenza A, like the A/California/04/09 (H1N1) and A/Hong Kong/1/1968 (H3N2), can even cause global pandemics.

Vaccination is the most effective way to prevent flu infection. Each year, several different flu strains are selected as vaccine strains based on surveillance data of the recent isolates, and the performance of the vaccines from the previous season. In recent decades, most vaccines are trivalent or quadrivalent, including one H1N1, one H3N2, and the Yamagata and Victoria type flu B.

Sino Biological offers recombinant Flu antigen products under its ProVir® viral antigen collection. The product line covers Hemagglutinin (HA), Neuraminidase (NA), and Nucleoprotein (NP) proteins, from all WHO-recommended vaccine strains in recent years. These antigens can be used to analyze vaccine-induced antibody response. In addition, Sino Biological also develops a large collection of monoclonal antibodies against the flu antigens. These reagents can help facilitate relevant assay development.