Johnson & Johnson said Wednesday it is buying Crucell N.V. for about $2.41 billion in a move that will boost the American health care company's vaccine business.

The move had been expected since September, when the companies announced they were in advanced talks. Johnson & Johnson already owns a 17.9 percent stake in the Dutch biotechnology company. The current offer is worth 1.75 billion euros, or 24.75 euros per share in cash for the remainder. That marks a 58 percent premium to Crucell's closing price on Sept. 16., the day before the companies announced a potential deal.

Johnson & Johnson, based in New Brunswick, N.J., has about $64 billion in annual sales and makes a broad range of products from Band-Aids to prescription drugs. It is new to the vaccine market and the Crucell buyout would give it vaccines aimed a childhood, endemic and respiratory diseases.

Johnson & Johnson said it will retain Crucell's existing facilities and senior management, along with current staffing levels. It will use Crucell as the center of its vaccines business and maintain headquarters in Leiden, Netherlands.

Crucell's board supports the deal.

The companies have been working together since 2009 to develop a universal flu vaccine and vaccines directed against infectious and noninfectious diseases.

"This potential combination would provide us with a new platform for growth and advances our goal to deliver integrated health care solutions, with particular emphasis on prevention," said Paul Stoffels, global head of pharmaceutical research and development at Johnson & Johnson, in a statement.