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Single HPV vaccine dose may be effective against cervical cancer

HPV is the most common sexually transmitted infection in the US, and persistent infection with certain types of the virus can cause cervical cancer. To prevent infection, the Centres for Disease Control and Prevention recommends that adolescents – both boys and girls – under the age of 15 years receive a two-dose schedule of the HPV vaccine.

To determine the effectiveness of other dose schedules, Dr Ana M Rodriguez, of The University of Texas Medical Branch at Galveston, and her colleagues examined information on females aged 9 to 26 years who were unvaccinated or who received one or more HPV vaccine doses between January 2006 and June 2015.

The analysis included 133,082 females (66,541 vaccinated and 66,541 unvaccinated). For females ages 15 to 19 years, those who received one, two, or three doses of the HPV vaccine had lower rates of preinvasive cervical disease than adolescents who were unvaccinated. Within five years, 2.65% of unvaccinated teens aged 15 to 19 years developed preinvasive cervical disease, compared with 1.62%, 1.99%, and 1.86% in the one-, two- and three-dose groups, respectively. The risk of preinvasive cervical disease was 36%, 28%, and 34% lower for adolescents who received one, two, and three doses, respectively, compared with adolescents who were unvaccinated.

For the youngest (less than 15 years old) and oldest age groups (20 years and older), the investigators did not find significant differences among the vaccinated groups in terms of risk for pre-invasive cervical disease.

"This study shows the impact of vaccinating at younger ages and its lasting long-term protection against cervical cancer," said Rodriguez. "It is important to educate parents about the need to vaccinate their children."

An accompanying editorial discusses the public health implications of the study's findings. "If one dose of HPV vaccine was sufficient for effective protection, HPV vaccine implementation and scale-up would require less logistics…, available doses could extend further, and the overall cost would be lower," the authors wrote.

Abstract
Background: Human papillomavirus (HPV)–related disease remains a significant source of morbidity and mortality, and this underscores the need to increase HPV vaccination to reduce the burden of the disease. The objective of this study was to examine the association between the number of HPV vaccine doses and the risk of histologically confirmed preinvasive cervical disease and high‐grade cytology.

Methods: This retrospective matched cohort study used administrative data from Optum's Clinformatics DataMart Database to identify females aged 9 to 26 years who received 1 or more quadrivalent HPV vaccine doses between January 2006 and June 2015. Cases and controls were matched on region, age, sexually transmitted disease history, and pregnancy. All had a Papanicolaou test ≥1 year after the date of the matched case's final dose. Cox proportional hazards models were used to examine the association between the number of HPV vaccine doses and the incidence of preinvasive cervical disease and high‐grade cytology. The Kaplan‐Meier method was used to estimate the cumulative incidence rate at the 5‐year follow‐up.
Results: The study included 133,082 females (66,541 vaccinated and 66,541 unvaccinated) stratified by the number of HPV vaccine doses and the vaccine initiation age. Among those aged 15 to 19 years, the hazard ratio (HR) for high‐grade cytology for the 3‐dose group was 0.84 (95% confidence interval [CI], 0.73‐0.97), whereas the HRs for histologically confirmed preinvasive cervical disease for 1, 2, and 3 doses were 0.64 (95% CI, 0.47‐0.88), 0.72 (95% CI, 0.54‐0.95), and 0.66 (95% CI, 0.55‐0.80), respectively.
Conclusions: The receipt of 1, 2, or 3 doses of an HPV vaccine by females aged 15 to 19 years was associated with a lower incidence of preinvasive cervical disease in comparison with unvaccinated females, and this supports the use of any HPV vaccination in reducing the burden of the disease.

Authors
Ana M Rodriguez, Burak Zeybek, Micah Vaughn, Jordan Westra, Sapna Kaul, Jane R Montealegre, Yu‐Li Lin, Yong‐Fang Kuo

[link url="https://www.sciencedaily.com/releases/2020/02/200210074246.htm"]Wiley material[/link]

[link url="https://acsjournals.onlinelibrary.wiley.com/doi/abs/10.1002/cncr.32700"]Cancer abstract[/link]

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