DOW JONES NEWSWIRES

Merck & Co. (MRK) has agreed to sell CSL Ltd.'s (CSL.AU) seasonal flu vaccine in the U.S. for a six-year period starting next fall, getting the drug giant into that sector.

Terms weren't disclosed for the deal between the companies, who have been vaccine-development partners since 1980.

Afluria was approved by the U.S. Food and Drug Administration two years ago. Merck said with selling the Australian company's vaccine, it will give Merck eight of the 10 vaccines on the recommended list for U.S. adults.

Vaccines have long been one of Merck's primary businesses, which showed strong growth in 2006 and 2007 but has had problems of late amid supply constraints and seen weakened demand. The unit's head will be leaving Nov. 1 ahead of the company's acquisition of Schering-Plough Corp. (SGP).

-By Kevin Kingsbury, Dow Jones Newswires; 212-416-2354; kevin.kingsbury@dowjones.com