Measuring vaccine effectiveness against persistent HPV infections: a comparison of different statistical approaches

Human Papillomavirus Vaccines

Human papillomavirus (HPV) vaccines are highly effective in preventing the transmission of HPV and thus downstream HPV-related lower genital tract neoplasias. First introduced in 2006, the HPV vaccine has demonstrated clinical efficacy in both men and women. Several commercially available vaccines now exist, but only one is available in the United States. Both prelicensure and postlicensure studies demonstrate robust safety profiles. HPV vaccines should be made available to everyone between the ages of 9 and 26 years of age. Newer vaccination recommendations in expanded populations rely on patient-provider shared decision making. Currently, available HPV vaccines offer little therapeutic benefit. Recent research has identified several new DNA vaccines and delivery modifications with early demonstrated success at eliminating prevalent HPV infections and precancerous lesions. Despite the success of the HPV vaccine, vaccination hesitancy and disinformation continue to threaten our ability to eliminate these deadly cancers. Informational, behavioral, and environmental interventions have mixed success in increasing vaccination rates, but several strategies do exist to increase rates of vaccination.

High vaccine effectiveness persists for ten years after HPV16/18 vaccination among young Dutch women

The current study describes the long-term effectiveness of three-dose HPV16/18 vaccination among Dutch women who were eligible for vaccination during a catch-up campaign and were followed in an observational cohort study. Ten years post vaccination, vaccine effectiveness (VE) was estimated using generalized estimating equation models. VE against persistent infections with vaccine type infections (HPV16/18) was high at 95.8%. For cross protective type persistent infections (HPV31/33/45) this was 64.6%. There were no indications of waning of protection over time. This indicates solid long-term protection is provided by the vaccine and is promising with regard to the future clinical impact.

Progression from human papillomavirus (HPV) infection to cervical lesion or clearance in women (18-25 years): Natural history study in the control arm subjects of AS04-HPV-16/18 vaccine efficacy study in China between 2008 and 2016

BACKGROUND

: Cervical cancer is the third most frequent cancer in Chinese women aged 15-44 years old. Human papillomavirus (HPV) is recognized as the main etiologic agent of cervical carcinomas. This study aims to better understand the natural history of HPV infections in Chinese women aged 18-25 years.

RESEARCH DESIGN AND METHODS

Data from 3,025 control arm women (AS04-HPV-16/18 vaccine trial) were analyzed to assess the probability of progression or clearance from a 6-month persistent infection (6MPI) to a cervical intraepithelial neoplasia grade 2 or greater (CIN2+), and the association with clinical determinants. Data were analyzed using univariate and multivariable Cox models.

RESULTS

A total of 1,324 women with 3,814 HPV infections were included, and 65.7% of the women had at least one 6MPI. Among those 6MPI, 5.0% progressed to CIN2+, while 61.0% cleared within 6 months. The risk of progression from 6MPI to CIN2+ was substantially higher for oncogenic versus non-oncogenic HPV types.

CONCLUSIONS

Oncogenic HPV infections showed lower clearance and higher risk to progress to CIN2+. These findings observed in a population of Chinese women, confirmed previous findings from multinational studies.

TRIAL REGISTRATION

: The PATRICIA and AS04-HPV-16/18 vaccine trials are registered at ClinicalTrials.gov (NCT00779766 and NCT00122681).