(Merck) MaxiVac Excell 5.0 is an aid in the control of disease associated with swine influenza virus subtypes H1N1 and H3N2. Give 2 ml IM to healthy pigs 5 weeks of age or older. Repeat 2-3 weeks later. Pigs nursing non-immune dams can be safely and effectively vaccinated at weaning. Pigs from immune dams should be vaccinated when maternal antibody levels will allow active immunization. Duration of immunity to H3N2 has been demonstrated by challenge to be at least two months following vaccination.