In the weekly science magazine Nature a piece of breakthrough news has been published in its 18th Jan,  2013 issue that the U.S. Food and Drug Administration  (FDA) has approved a new seasonal influenza vaccine through the use of novel DNA recombinant technology.  The trivalent vaccine named Flublok  has been made for the prevention of seasonal influenza for 18-40 years old people . It was made using insect virus (baculovirus) expression system. Flublok contains three, full-length, recombinant hemagglutinin (HA)  proteins to help protect against two influenza virus A strains, H1N1 and H3N2, and one influenza virus B strain. A survey conducted on 2,300 people to a placebo group of similar size revealed that recombinant DNA based technology, Flublok was about 44.6 percent effective against all circulating influenza strains.