In a perfect example of how the Affordable Care Act is broadening access to relatively low-cost and potentially life-saving interventions, a new study finds that the health reform law likely led more than 1 million young women to seek out the human papillomavirus vaccine and protect themselves against cervical cancer.

In a study published this month in Health Affairs, researchers studied the impact of two ACA provisions: one requiring insurance providers to extend dependent coverage through age 26 and another that required insurers to offer a range of preventive services, such as immunizations, without cost-sharing. The study noted that prior to the ACA, young adults had the lowest rate of insurance coverage among all age groups, and few states required private health plans to cover vaccines for adults. Plus, the HPV vaccine, which protects against two strains of HPV responsible for 70 percent of cervical cancers, isn’t cheap to pay for out of pocket — it cost upward of $400 for all three doses. Federal health officials recommend that all boys and girls should receive the three doses at ages 11 or 12, though young women can get the vaccine through age 26 and young men through age 21. Study authors Brandy Lipton and Sandra Decker write:

While general measures of health care use are usually a logical starting point in analyses of the effects of health insurance expansions, most young adults have few health problems. This fact may explain why previous studies have not found a positive effect of the dependent coverage provision on the percentage of young adults having at least one health care visit in the past year or the percentage having obtained a flu shot in the past year, a service that is low cost and may be obtained without a physician office visit. The HPV vaccine, on the other hand, is a service with a high out-of-pocket cost that is recommended for young women in the age group targeted by the dependent coverage provision of the ACA. This makes the vaccine an especially strong example to consider in examining the effects of coverage provisions under the ACA.

To examine whether more young women were seeking out the potentially life-saving vaccine post-ACA, researchers examined data from the National Health Interview Survey between 2008 and 2012, with the final data sample consisting of just more than 10,000 women ages 18 to 26. They found that women ages 19 to 25 were more likely to report receiving the HPV vaccine after the ACA policies went into effect compared to before the policies took effect. In particular, the study found that among that age group, the ACA provisions increased the likelihood of HPV vaccine initiation by 7.7 percentage points and vaccine completion (receiving all three doses) by 5.8 percentage points. In simpler terms, that means 1.1 million young women began the HPV vaccine series and 854,000 young women completed the vaccine series.

The study authors noted that there was no “detectable” difference in women’s awareness of the HPV vaccine before and after the ACA polices were enacted, and so it is unlikely that a new awareness, as opposed to insurance changes, is responsible for the uptick in HPV immunization. The study also estimated that because a large percentage of the study sample was insured both before and after implementation of the two ACA policies, most of the increase in HPV vaccine initiation was likely due to more generous health benefits and cost sharing.

“By increasing the percentage of young women with any source of insurance and decreasing the out-of-pocket cost of the vaccine among those who would have been insured in the absence of the ACA, implementation of the ACA provisions may have facilitated uptake of the HPV vaccine among adult women,” the study stated.

To request a full copy of the study, visit Health Affairs.

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for more than a decade.