A single dose of the HPV vaccine could be enough to protect against infections which cause 70% of cervical cancers, new research suggests.
Doctors found just one lot of the bivalent human papillomavirus vaccine may offer a similar level of protection as the two or three doses normally given.
Girls aged 12 to 13 are offered HPV vaccination on the NHS to protect against cervical cancer, the UK's most common cancer in women under the age of 35.
Experts said the findings could be a "game changer" in how women are vaccinated against infections which cause the disease.
Researchers in America analysed data from two trials involving more than 7,400 healthy women aged 18 to 25 years old and more than 18,600 healthy women aged 15 to 25 years from around the world.
They found "high vaccine efficacy" against HPV-16/18 infections regardless of the number of doses the women received, according to a study published in the Lancet Oncology.
The same result was also seen in women with no sign of HPV infection before or at the time of their first vaccination, suggesting the findings were relevant to "sexually-naïve girls" in the recommended age range for HPV vaccination, the report added.
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Co-lead author Dr Aimée Kreimer, from the National Cancer Institute, said: "Our findings question the number of HPV vaccine doses truly needed to protect the majority of women against cervical cancer, and suggest that a one-dose schedule should be further evaluated.
"If one dose is sufficient, it could reduce vaccination and administration costs as well as improve uptake. This is especially important in less developed regions of the world where more than 80% of cervical cancer cases occur."
In the UK, 2,900 women a year are diagnosed with cervical cancer - around eight women every day, NHS Choices said.
Professor Margaret Stanley, from the Department of Pathology at University of Cambridge, said the findings "could be the game changer for the implementation and uptake of these vaccines worldwide".
She said: "Delivering one dose rather than two or three would be easier in settings with little medical infrastructure and crucially cheaper, not just in vaccine costs but delivery costs."
Dr Mark Jit, from the London School of Hygiene & Tropical Medicine, said: "Many countries, including the UK, recently switched from giving three doses to giving two doses of the HPV vaccine to girls up to 14 years old.
"This followed findings from Costa Rica and other studies that two doses of vaccine may be enough to protect women from cervical cancer. The latest news that even one dose may be protective holds promise, although further studies are needed before we will be ready to consider a one dose schedule."