Researchers have developed a vaccine against four common viruses that cause infections leading to cervical cancer.  Studies show that almost everyone who received the vaccine was protected against the pre-cancerous conditions. 

Human papilloma viruses (HPVs), strike almost every woman at some time in her life.  The viruses are sexually transmitted, usually harmless and eventually disappear in women with healthy immune systems. 

But health officials are concerned about HPVs in women who are not healthy. The World Health Organization (WHO) estimates almost 300,000 women die each year of cervical cancer.  Most of them are in the developing countries where screening is not commonly available, according to Dr. Luisa Lina Villa, of the Ludwig Institute for Cancer in Brazil.

"This is why the promise for some of these vaccines is so well expected and well received in the community," she said.

Dr. Villa and colleagues have developed a vaccine that kept 90 percent of young women from becoming infected with four types of HPV virus.  The vaccine protected 100 percent of the women who became infected with the virus against the development of genital warts, a condition that often leads to cervical cancer, and abnormal cervical lesions, another precursor to cervical cancer. 

The study lasted three years, and involved four shots given during the first six months.  Dr. Villa says researchers don't know whether additional HPV booster injections are needed.

More studies will be conducted looking at the vaccines effectiveness.

Drug companies, including Merck Pharmaceuticals, are also working to develop vaccines against cervical cancer.

Mark Feinberg, of Merck's vaccine development program, says the task ahead is to deliver the vaccine where it is needed.

"That's just a very startlingly, encouraging result," he said.  "Yet, how do we go about getting that to all the people around the world who need it?  Clearly, we can't do it on our own.  We need partners.  We need a good idea about what the market would be and what production capacity would be."

The study on the HPV vaccine was published in the international journal Lancet Oncology.