For Young Women, It’s Not Too Late For HPV Vaccination

Gardasil 9 nonavalent HPV vaccine is anticipated to prevent more CIN2+ cases than the quadrivalent HPV vaccine

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A new study confirms the effectiveness of quadrivalent human papillomavirus (HPV) vaccine in women up to 20 years of age who receive all 3 doses.

According to this population case-control study of over 25,000 women in California aged 14-20 years, catch-up HPV vaccinations are effective against the risk of cervical precancers, if women receive all 3 HPV vaccine doses.

But, these researchers say in a press release that more research is needed in women aged 21-26 years.

This research is important, since every year, approximately 19,400 women are affected by cancers caused by HPV, says the Centers for Disease Control and Prevention (CDC). 

This study analyzed cases of CIN2+ or CIN3+, which is cervical intraepithelial neoplasia - abnormal growth of cells on the surface of the cervix that could potentially lead to cervical cancer.

"Our findings show that women who did not receive the full vaccine series at age 11-12 can still benefit from significant protection if they receive the full 3 doses of vaccine by the age of 20,” says lead author Michael J. Silverberg, a research scientist with Kaiser Permanente Northern California's Division of Research.

In the USA, HPV vaccination is recommended for girls aged 11-12, says the CDC. The HPV vaccine is approved as a 3-dose series.

And, the CDC also allows for a 2-dose series for girls aged 9-14.

For those who did not receive the vaccine at this age, catch-up vaccination is recommended for girls and women aged 13-26 years.

The strongest protection against CIN2+ and CIN3+ was identified in women who had received at least 3 vaccine doses and had received their first dose aged 14-17 years or aged 18-20 years.

No significant protection was found in women who received their first dose aged 21 years or older, or who received fewer than the full 3 doses in the series.

Writing commentary, Sarah Dilley and Warner Huh, Division of Gynecologic Oncology, University of Alabama, Birmingham, advised caution before abandoning the practice of catch-up vaccination in women aged over 21 years, “Given that prospective efficacy studies have shown benefits for catch-up vaccination up to at least age 26 years, more data is needed before abandoning this practice."

Importantly, this study looked at the effectiveness of the quadrivalent HPV vaccine and not of the more recently introduced Gardasil 9, nonavalent HPV vaccine, which is anticipated to prevent more CIN2+ cases than the quadrivalent HPV vaccine.

Therefore, further research, including women aged over 21 years, will be important as new vaccines become more widely used.

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HPV is transmitted through intimate skin-to-skin contact, and can be passed even when an infected person has no signs or symptoms.

You can get HPV by having vaginal, anal, or oral sex with someone who has the virus. It is most commonly spread during vaginal or anal sex, says the CDC.

HPV is so common that nearly all men and women get it at some point in their lives.

HPV vaccination services are found in most pharmacies and physician offices in the USA.

To schedule a vaccination appointment, please visit this page.

The CDC Vaccine Price List provides HPV vaccine prices for general information.

And vaccine discounts can be found here.

Vaccines, like any medicine, can have side effects, says the CDC. You are encouraged to report negative side effects of vaccines to the FDA or CDC.

This study was funded by the US National Cancer Institute. No conflicts of interest were disclosed by these researchers.