A study comparing nearly 2 million vaccinated and unvaccinated adolescent girls over 10 years found the girls vaccinated with a quadrivalent HPV vaccine were 4.4 times more likely than their unvaccinated counterparts to develop rheumatoid arthritis.

A type of human papillomavirus (HPV) vaccine widely used throughout the world, but not in the U.S., may increase the risk of developing four autoimmune disorders, according to a study published last week in Vaccine.

The Colombian retrospective cohort study compared the health records of nearly 2 million vaccinated and unvaccinated adolescent girls over 10 years and found the girls vaccinated with a quadrivalent HPV vaccine were 4.4 times more likely than their unvaccinated counterparts to develop rheumatoid arthritis.

Quadrivalent HPV vaccines target four high-risk strains of HPV, compared with Merck’s Gardasil 9 vaccine, the only HPV vaccine distributed in the U.S., which targets nine strains.