Source: New York Times | Page: A15
By: McNeil, Jr., Donald G.
Sanofi Pasteur and GlaxoSmithKline Biologicals have created quadrivalent vaccines that protect against four strains of flu. Only one A and one B strain were covered by the flu vaccine until 1978, when a second A strain was added. An additional B strain has been added due to the difficulty of predicting which one will be dominant that year. The new vaccines—which have not yet received U.S. Food and Drug Administration approval—will protect against A(H1N1), A(H3N2), and the B strains Victoria and Yamagata.