According to the World Health Organization (WHO), vaccination is the most effective way to prevent infection and severe disease caused by influenza viruses. Human influenza is easily transmitted from person to person and cause seasonal flu epidemics. In contrast, animal influenza viruses do not easily transmit between humans. However, if mutate, they can cause large epidemics or a pandemic because people do not have immunity to new influenza viruses. The largest pandemic in 1918 caused estimated 50 million deaths worldwide. Therefore recently emerging novel, avian-origin influenza H5N1, H9N2, H7N9 and H10N8 viruses are raising global pandemic concerns. Vaccine development for pandemic viruses is a priority for the U.S. Department of Health & Human Services (DHHS).

Recently, two recombinant virus-like particle (VLP) vaccines were reported in Vaccine, an international scientific journal on vaccine research. One VLP vaccine contained H10 protein from H10N8 virus. Another vaccine represented a unique VLP structure that co-localized H5, H7, H9 and H10 proteins and was designed to provide immunity to all four potentially pandemic influenza subtypes. Vaccines were prepared by Medigen and evaluated in collaboration with the Centers for Disease Control and Prevention in an experimental ferret model, which represents a “gold standard” for influenza vaccines.

Animals were vaccinated with VLPs and then challenged with live H10N1 virus. After challenge, all vaccinated animals showed significantly reduced titers of replicating virus in the respiratory tract indicating protective effect of vaccination with either H10 VLPs or with H5/H7/H9/H10 VLPs. The results show that recombinant VLPs can be used for vaccination against potentially pandemic influenza viruses. For more information, see Vaccine 2016; 34:5235-5242.