Swine flu cases may have peaked , but the 1918 H1N1 virus will probably return . Public health officials to watch the Southern Hemisphere to see what 2009 H1N1 does . Scientists are working on a vaccine against 2009 H1N1 ; wo n't be ready for 2009 . Secondly , the 2009 H1N1 lacks a gene that is present in highly virulent flu viruses , such as the one in 1918 . 2009 New York lacks a gene that is present in very virulent flu viruses , like 2009 strain .
Swine flu cases may have peaked , but the 1918 H1N1 virus will probably return . Public health officials to watch the Southern Hemisphere to see what 2009 H1N1 does . Scientists are working on a vaccine against 2009 H1N1 ; wo n't be ready for 2009 . 2009 New York lacks a gene that is present in very virulent flu viruses , like 2009 strain .