Although the main purpose of the human papillomavirus vaccine is to protect girls from cervical cancer, genital warts caused by certain types of the virus is also prevented by the vaccine. Now, researchers have found that fewer doses of the vaccine still results in risk reduction of genital warts.

Outcomes of the latest study, which researchers say is the first to report a link between human papillomavirus (HPV) vaccination and genital warts by vaccine dose level, were recently published in JAMA.

The team notes that typical HPV vaccination requires three doses, but this latest study shows that two doses in girls younger than 17 was linked with a “considerable reduction in risk” of genital warts, also known as condyloma.

“Determining vaccine dose-level protection is essential to minimize program costs and increase mass vaccination program feasibility,” write the authors.

So, to determine the association between number of doses and genital warts, the team, led by Eva Herweijer of the Karolinska Institutet in Stockholm, Sweden, assessed an open cohort of all females between the ages of 10-24 living in Sweden.

Using the Swedish nationwide population-based health data registers, the team looked at data on over 1 million girls who were followed up regarding HPV vaccination and first occurrence of condyloma between 2006 and 2010.