HPV Vaccination of Girls in the U.S.-Affiliated Pacific Islands, 2013–2023

Cervical cancer is the fourth most common cancer among women worldwide, and the World Health Organization's Western Pacific Region — home to the U.S.-affiliated Pacific Islands (USAPI) — has a quarter of all estimated cases. The Marshall Islands has the world's highest age-standardized rate: 74 per 100,000 women. Nearly all cervical cancers are caused by human papillomavirus (HPV), and HPV vaccines, licensed since 2006, could prevent about 75% of them.

CDC recommends HPV vaccination for boys and girls at 11–12. This report focuses on girls, to track the WHO goal that by 2030, 90% of girls finish the HPV series by age 15. It is the first comprehensive look at trends since the vaccine arrived in the islands.

The islands and their programs

The USAPI are three U.S. territories — American Samoa, Guam and the Northern Mariana Islands — and three freely associated nations — the Federated States of Micronesia, the Marshall Islands and Palau. HPV vaccination began between 2007 and 2016, mostly through school-located programs. This report covers five jurisdictions; Guam is measured by the National Immunization Survey instead.

• Data: each jurisdiction's immunization information system, counting girls 13–17 with an active record, as of December 31 each year from 2013 to 2023.
• Series completion: three doses, or two if started before 15 with the doses at least 5 months (minus 4 days) apart.

Coverage in 2023

Dropout: girls who started the series but had not finished it by year's end.

• The Northern Mariana Islands is the only jurisdiction already above the WHO 2030 goal.
• American Samoa's completion rose from 78.0% to 82.8% between 2022 and 2023; at that pace it would reach 90% by 2025.
• Since 2013, first-dose coverage rose by 35.2–72.8 percentage points across jurisdictions, and completion by 35.3–72.9 points.
• Palau is the exception: coverage peaked in 2020 (71.6% first dose, 59.0% complete) and has since fallen, while dropout rose from 17.2% in 2021 to 25.2% in 2023. Everywhere else, dropout fell over the decade.

Coverage with at least one HPV dose, 2013–2023. Image from the Centers for Disease Control and Prevention

HPV series completion, 2013–2023. Image from the Centers for Disease Control and Prevention

Why the gap?

Access. American Samoa and the Northern Mariana Islands offer the vaccine both in schools and in public health clinics, funded through the Section 317 Immunization Program and Vaccines for Children (VFC). The three freely associated nations get Section 317 funds but are not eligible for VFC, so with limited supply they have not been able to offer the vaccine consistently outside schools.

School reach. School-located vaccination is an evidence-based way to raise coverage, but it misses girls who are not in school. Secondary school enrollment among girls is about 66% in Micronesia, 83% in the Marshall Islands and 80% in Palau, compared with about 97% in American Samoa and the Northern Mariana Islands. Reaching out-of-school girls is also an equity issue — some research suggests girls who leave school are more likely to get sexually transmitted infections such as HPV.

The pandemic. School programs may have paused while schools were closed for COVID-19. In Palau, coverage was rising among girls who reached 11–12 before 2020 but not among those who reached that age in 2020 or later — possible evidence of the pandemic's toll.

Limitations

1. Results depend on the completeness and accuracy of each registry; checks since 2016 found them high, but earlier data were not evaluated.
2. Registries can overcount active patients (people who moved away or died), which would understate coverage; recent census data were not available for every jurisdiction, so exclusion rules were applied instead.
3. Guam's survey-based estimates are not directly comparable and were not included.

What's needed

Only two of the five jurisdictions have met or are on track for the WHO 2030 goal. Evidence-based strategies adapted to local conditions — and targeted help for groups hit hardest, including girls who reached vaccination age during the pandemic — would help those lagging behind.

Sources

Based on "Human Papillomavirus Vaccination Coverage Among Adolescent Girls Aged 13–17 Years — U.S.-Affiliated Pacific Islands, 2013–2023," by Ashley Tippins, Glodi Mutamba, E.M. Boyd, Kelsey C. Coy and Jennifer L. Kriss, Morbidity and Mortality Weekly Report 73(33), Centers for Disease Control and Prevention; a work of the United States government in the public domain. The source says coverage rose every year everywhere but Palau, but its own table shows dips in the Northern Mariana Islands and the Marshall Islands in 2014–2015, so that claim is left out.