"Virus" vaccines could create new, worse diseases, researchers warn

<body leftmargin="0" bgcolor="#000060" text="#FFFFFF" link="#FFFF00" vlink="#FF9900"> <b> <h1 class="title"><font face="Arial" size="4">"Virus" vaccines could create new, worse diseases, researchers warn</font></h1> </b><p class="title"><font face="Arial" size="1">Posted August 9<br> World Science staff</font> </p> <p class="title"> <font size="2"><b><span style="font-family: Arial; mso-fareast-font-family: Times New Roman; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">Many vaccines are designed using a weakened or dead form of a virus in order to stimulate our immune systems. The idea is to prepare our systems to fight off the real virus when it comes.</span></b></font> </p> <p class="title"><font size="2"><b><span style="font-family: Arial; mso-fareast-font-family: Times New Roman; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">But two recent studies warn that such vaccines, intended to prevent disease, may end up creating new and more dangerous ones. </span></b></font> </p> <p class="title"> <font size="2"><b><span style="font-family: Arial; mso-fareast-font-family: Times New Roman; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"> In the June 22 advance online edition of the journal <i>PLOS Biology</i>, the University of Edinburgh's Margaret Mackinnon and Andrew Read report that they created more virulent strains of the malarial parasite <i> Plasmodium</i> by transferring the parasite, by syringe, among various mice immunized against it. </span></b></font> </p> <p class="title"> <font size="2"><b><span style="font-family: Arial; mso-fareast-font-family: Times New Roman; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"> This probably happened because the most virulent parasites survived the vaccination-induced defenses, and further evolved within the environment of the host mice, they add. </span></b></font> </p> <p class="title"> <font size="2"><b><span style="font-family: Arial; mso-fareast-font-family: Times New Roman; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"> And in the June 19 issue of the medical journal <i>Lancet</i>, New York Medical College's Stephen J. Seligman and colleagues warn that viral vaccines - based on "attenuated" or disabled viruses - could recombine, or mix genes with, with normal viruses to create new ones with undesired properties. They recommend an international authority be assigned to review new possible uses of vaccine viruses.</span></b></font> </p> </body>