Oct. 16 (HealthDay News) -- GlaxoSmithKline's Cervarix vaccine has been approved by the U.S. Food and Drug Administration to prevent the leading cause of cervical cancer, the Associated Press reported Friday.

The British drug maker said it expects the vaccine will be available in U.S. pharmacies later this year. In 2007, the FDA requested additional data from Glaxo, delaying Cervarix's release, the wire service said. The vaccine is available in almost 100 other countries.

Cervarix inhibits human papilloma virus (HPV) strains 16 and 18, which cause 75 percent of cervical cancers, the AP said. Of the more than 100 identified strains of HPV, about 15 are known to cause cervical cancer. HPV, spread mostly through sexual contact, affects some 6 million people in the United States each year, although most cases show no symptoms and resolve on their own.

Cervarix will compete with Merck & Co.'s Gardasil, launched in the United States in 2006, the wire service said.

Clinical side effects of Cervarix include injection-site pain and swelling, fatigue and headache.