The country is still gripped by the heat of summer, but federal officials are already thinking about a common cold weather problem.

The flu bug is the target of new seasonal vaccines announced today by the U.S. Food and Drug Administration.

The influenza vaccines include new strains of the virus likely to appear during the 2008-2009 season. The strains were identified in a group effort with the FDA, the World Health Organization, U.S. Centers for Disease Control and Prevention, and other institutions after study of virus samples and patterns collected around the globe during the last year.

“One of the biggest challenges in the fight against influenza is producing new vaccines every year,” said Jesse L. Goodman, M.D., M.P.H., director of FDA’s Center for Biologics Evaluation and Research. “There is no other instance where new vaccines must be made every year. The approval of flu vaccines is a part of FDA’s mission to promote the health of Americans throughout the year.”

While many Americans reported getting the flu last year, even after receiving a flu shot, experts say vaccination remains the cornerstone of preventing the contagious respiratory illness caused by influenza viruses.

The CDC says an average of 5 to 20 percent of the U.S. population gets the flu annually. Of those, more than 200,000 are hospitalized from flu complications and there are about 36,000 flu-related deaths.