Chiron Gets Subpoena Over Vaccine Debacle  NEW YORK (Reuters) - A federal grand jury is investigating  Chiron Corp.'s &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=CHIR.O target=/stocks/quickinfo/fullquote"&gt;CHIR.O&lt;/A&gt; failure to deliver vaccine for the  coming flu season, the company disclosed on Tuesday.