A study conducted by Merck & Co. indicates that allergic reactions to Gardasil were uncommon. The vaccine is used to treat cervical cancer. Research was conducted on 25 Australian girls who were considered to be hypersensitive to Gardasil.

It was found that only three of the 25 schoolgirls had probable hypersensitivity to Gardasil. Thus the researchers concluded that true hypersensitivity is uncommon.

The U.S. Centers for Disease Control and Prevention had reported that girls and young women who were given Gardasil vaccine could face symptoms which make them faint, have an allergic reaction, blood clot or other adverse reaction.

The allergic reactions of the vaccine include hives, skin rash and swelling.

Gardasil has been approved for use by girls and young women as a  protection against four types of the sexually transmitted human papillomavirus, or HPV, two of which are most likely to cause cervical cancer.

A course of three doses of Gardasil is needed to provide protection against the papillomavirus.