Introduction. In the United States (US), the 4-valent and 2-valent human papillomavirus (HPV) vaccines have been available since 2006. In 2009, the 9-valent vaccine became available. This study assessed the impact of HPV vaccine introduction on the incidence of cervical cancer among young females in the US.

Methods. We used data from United States Cancer Statistics (USCS) 2001–2018 database among US females 15–34 years old. We compared the 4–year average annual incidence of invasive cervical cancer in 4 years before HPV vaccine introduction (2003-2006) and the latest 8 years in the vaccine era (2011-2014 and 2015-2018). Joinpoint regression models were fitted to identify the discrete joints (year) that represent statistically significant changes in direction of the trend.

Results. The 4–year average annual incidence rates for cervical cancer among 15-24 year old females were 3.9 per 1,000,000 in 2015–2018, 6.1 in 2011–2014, and 8.3 in 2003–2006. Among 25-34 year old females, the incidence rates were 82.0 in 2015–2018, 76.8 in 2011–2014, and 88.33 in 2003–2006. Joinpoint analyses of cervical cancer incidence among 15-24 year old females revealed a significant joint at 2011 (APC for 2001-2011 -2.2, 95% CI -4.4 – 0 and APC for 2011-2018 -10.3, 95% CI -14.7 – -5.6). Among 25-34 year old females, there was also one significant joint at 2011 (APC for 2001-2011 -2.3, 95% CI -2.9 – -1.8 and APC for 2011-2018 1.3, 95% CI 0.3 – 2.2).

Conclusions. Cervical cancer incidence in the vaccine era was significantly lower than the pre-vaccine era among young women 15-24 years old. There was further decrease in the incidence of cervical cancer among young women 15-24 years old after 2011. This may indicate early effects of the introduction of HPV vaccination, improved HPV vaccine coverage, and availability of the 9-valent vaccine which protects against additional oncogenic HPV types.