Gardasil, the cervical cancer vaccine developed by Merck & Co. which protects against the human papillomavirus, or HPV, may cause allergic reactions, including nausea, itchy red rash, difficulty breathing and other symptoms. But the total number of reactions remains miniscule, a study conducted by Australian researchers found.

The team of Australian researchers led by Dr. Julia Brotherton of The Children’s Hospital at Westmead studied 114,000 young women vaccinated with Merck & Co’s Gardasil vaccine as part of a 2007 vaccination program in New South Wales. Overall, 12 young women had confirmed anaphylactic reactions after getting the vaccine.

Researchers concluded the rates remain rare and shouldn’t discourage use of the vaccine, health workers should be prepared to “rapidly detect and treat adverse events, including fainting, anxiety and immediate hypersensitivity reactions,” wrote Dr. Neal A. Halsey of the Institute for Vaccine Safety at Johns Hopkins Bloomberg School of Public Health in a commentary accompanying the Australian study published in the Canadian Medical Association Journal.

Gadasil prevents infections caused by four types of HPV. There are over 100 different strains of the human papillomavirus and about 40 of them trigger to genital infections. Of those 40, about half can cause cancer. The vaccine is efficient only regarding the prevention of four types of the virus that may lead to 90 percent of genital warts and 70 of cervical cancer.  

FDA gave its approval for Gardasil use in girls and women from 9 to 26. A recent study carried out by the Harvard School of Public Health concluded that, if the vaccine is administered to females before they become sexually active, the measure proves very cost-effective in terms of preventing the cancer. The U.S. Centers for Disease Control and Prevention currently recommends that 11- and 12-year-old girls get a routine vaccine, as most girls of this age are not yet sexually active and will achieve a maximum protection.