Health Concerns Most Americans Immune to Swine Flu September 29, 2010September 29, 2010 RSB Staff antibodies, contadious, H1N1, immune, influenza, mutation, strain, Swine Flu, vaccinated, vaccine, virus If the H1N1 virus is to continue its contagious ways this coming flu season, it will have to adapt to a highly immune population, according to a new study. Epidemiologists estimate that 183 million Americans