A story in yesterday's Econ 2009 special report incorrectly said that Merck & Co. Inc. has had trouble producing enough Gardasil vaccine. Merck said it had an ample supply of Gardasil, but had fallen behind in producing its adult varicella vaccine, Zostavax, for shingles. Merck said it continued to receive and fill orders for Zostavax and would clear most current back orders before the end of 2008.