Quadrivalent HPV vaccine effectiveness against high‐grade cervical lesions by age at vaccination: A population‐based study

Human papillomavirus (HPV) types 16/18, included in HPV vaccines, contribute to the majority of cervical cancer, and a substantial proportion of cervical intraepithelial neoplasia (CIN) grades 2/3 or worse (CIN2+/CIN3+) including adenocarcinoma in situ or worse. The aim of this study was to quantify the effect of quadrivalent HPV (qHPV) vaccination on incidence of CIN2+ and CIN3+. A nationwide cohort of girls and young women resident in Sweden 2006–2013 and aged 13–29 (n = 1,333,691) was followed for vaccination and histologically confirmed high‐grade cervical lesions. Data were collected using the Swedish nationwide healthcare registers. Poisson regression was used to calculate incidence rate ratios (IRRs) and vaccine effectiveness [(1‐IRR)x100%] comparing fully vaccinated with unvaccinated individuals. IRRs were adjusted for attained age and parental education, and stratified on vaccination initiation age. Effectiveness against CIN2+ was 75% (IRR = 0.25, 95%CI = 0.18–0.35) for those initiating vaccination before age 17, and 46% (IRR = 0.54, 95%CI = 0.46–0.64) and 22% (IRR = 0.78, 95%CI = 0.65–0.93) for those initiating vaccination at ages 17–19, and at ages 20–29, respectively. Vaccine effectiveness against CIN3+ was similar to vaccine effectiveness against CIN2+. Results were robust for both women participating to the organized screening program and for women at prescreening ages. We show high effectiveness of qHPV vaccination on CIN2+ and CIN3+ lesions, with greater effectiveness observed in girls younger at vaccination initiation. Continued monitoring of impact of HPV vaccination in the population is needed in order to evaluate both long‐term vaccine effectiveness and to evaluate whether the vaccination program achieves anticipated effects in prevention of invasive cervical cancer.     

Incidence of cervical lesions in Danish women before and after implementation of a national HPV vaccination program

Purpose

Approximately 70 % of cervical cancers and about 50 % of high-grade cervical precursor lesions are caused by human papillomavirus (HPV) types 16 and 18. Denmark introduced the quadrivalent HPV vaccine into the vaccination program for 12-year-old girls in 2009 supplemented by a first catch-up program for 13–15-year-old girls in 2008, and a second program for women up to the age of 27 years in 2012; all with high vaccination coverage. The aim of this study was to evaluate the effectiveness of the vaccine by comparing the incidence trends of cervical lesions before and after its introduction.

Methods

Incident cases of cervical lesions were identified from the nationwide Pathology Data Bank. Age-specific incidence rates were estimated for six age groups, and Poisson regression was used to calculate estimated annual percentage change (EAPC).

Results

The incidence of atypia or worse (atypia+) and cervical intraepithelial neoplasia grade 2 or worse (CIN2+) increased in all age groups in 2000–2010. After introduction of the quadrivalent HPV vaccine into the vaccination program, the incidence of atypia+ decreased significantly in women younger than 18 years (EAPC ?33.4 %; 95 % CI ?49.6; ?12.0) and in 18–20-year-old women (EAPC ?12.6 %; 95 % CI ?19.3; ?5.3). The incidence of CIN2+ also decreased significantly in 18–20-year-old women (EAPC ?14.8 %; 95 % CI ?21.6; ?7.5) in 2010–2013, but no significant decrease was seen in older age groups.

Conclusion

The incidence of cervical lesions decreased significantly in age groups with high HPV vaccine coverage, indicating an early effect of HPV vaccination.     

Risk of cervical intraepithelial neoplasia grade 2 or worse after conization in relation to HPV vaccination status

Human papillomavirus (HPV) is essential for developing cervical cancer and precancerous lesions. Currently, three vaccines are available, which are effective as prophylaxis against HPV infection, however, limited knowledge exists about the possible effect of vaccinating women treated with conization to prevent recurrence. The aim of our study was to examine the risk of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) after conization according to HPV vaccination status. Using Danish nationwide registries, we identified women diagnosed with CIN3 on the cone (2006–2012) and their HPV vaccination status. Vaccinees were defined as women vaccinated between 3 months before until 1 year after conization. The women were followed from 1 year after conization until diagnosis of CIN2+, conization, death, emigration or end of follow-up. Cox proportional hazard regression was used to estimate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) of CIN2+ comparing vaccinees with nonvaccinees. The HR was adjusted for age, histology on cone, education, year of conization, repeat conizations and CIN2+ lesions between conization and start of follow-up. Altogether 17,128 women were included (2,074 vaccinees). There was a statistically nonsignificant lower risk of CIN2+ among vaccinees (HR_adjusted = 0.86, 95% CI: 0.67–1.09). Women vaccinated 0–3 months before tended to have a slightly lower HR of CIN2+ (HR_adjusted = 0.77, 95% CI: 0.45–1.32) than women vaccinated 0–12 months after conization (HR_adjusted = 0.88, 95% CI: 0.67–1.14), although not statistically significantly different. Our results add to the current knowledge about the potential clinical effect of vaccination as an adjunct to conization of high-grade cervical neoplasia to decrease risk of recurrence.     

Human papillomavirus testing and genotyping in cervical screening

Mass vaccination against human papillomavirus (HPV) genotypes 16 and 18 will, in the long term, reduce the incidence of cervical cancer, but screening will remain an important cancer control measure in both vaccinated and unvaccinated women. Since the 1960s, cytology screening has helped to reduce the incidence of cervical cancer, but has a low sensitivity for high-grade cervical intraepithelial neoplasia (CIN) and requires frequent testing. Several HPV tests have become available commercially. They appear to be more sensitive for high-grade CIN, and may further reduce the incidence of cervical cancer compared with cytology. However, they are associated with an increased frequency of positive tests without underlying CIN, and therefore increase the need for colposcopy and repeated testing. This problem will pose a major challenge for switching from cytology-based to HPV-based screening. The aim of this article is to discuss the role and the use of HPV tests and HPV genotyping in unvaccinated women.     

HPV type-specific trends in cervical precancers in the United States, 2008 to 2016

Declines in cervical intraepithelial neoplasia grades 2 to 3 and adenocarcinoma in situ (CIN2+) observed among young women suggest impact from human papillomavirus (HPV) vaccination. To further evaluate vaccine impact including cross-protection and type replacement, we described high-risk (HR)-HPV type-specific cervical precancer incidence rates among women aged 20 to 39 years, 2008 to 2016. We analyzed cross-sectional population-based data on 18 344 cases of CIN2+ from a 5-site surveillance system. Diagnostic specimens were tested for individual HPV types, including 14 HR-HPV types (HPV16/18/31/33/35/39/45/51/52/56/58/59/66/68). We estimated age-specific annual HR-HPV type-specific CIN2+ incidence per 100 000 screened women for individual types, vaccine HR-HPV types (HPV16/18) and nonvaccine HR-HPV types (non-HPV16/18). We evaluated trends using average annual percent changes (AAPC) and 95% confidence intervals (CI), and estimated total declines by comparing 2015-2016 to 2008-2009 using incidence rate ratios. Among 20-24-year-olds, HPV16/18-CIN2+ declined from 2008 through 2016 (AAPC: −21.3%, 95% CI: −28.1%, −13.8%), whereas no trend was observed for non-HPV16/18-CIN2+ (AAPC: −1.8%, 95% CI: −8.1%, 4.9%). After 2010, CIN2+ among 20-24-year-olds was more often caused by nonvaccine vs vaccine HR-HPV types. No significant declining trends were observed in older age groups. In 2015-2016 compared with 2008-2009, HPV16-CIN2+ declined 78%, HPV18-CIN2+ 72% and HPV31-CIN2+ 51% among 20-24-year-olds; no increases were observed in type-specific CIN2+ incidence. Among 25-29-year-olds, HPV16-CIN2+ declined 18%; CIN2+ attributed to seven nonvaccine types increased significantly. No significant declines were observed in older groups. Significant declines in HPV16/18-CIN2+ in 20-24-year-olds and HPV16-CIN2+ in 25-29-year-olds corroborate impact of HPV vaccination. A declining trend in HPV31-CIN2+ is consistent with cross-protection from vaccination.     

Human papillomavirus testing and genotyping in cervical screening

Mass vaccination against human papillomavirus (HPV) genotypes 16 and 18 will, in the long term, reduce the incidence of cervical cancer, but screening will remain an important cancer control measure in both vaccinated and unvaccinated women. Since the 1960s, cytology screening has helped to reduce the incidence of cervical cancer, but has a low sensitivity for high-grade cervical intraepithelial neoplasia (CIN) and requires frequent testing. Several HPV tests have become available commercially. They appear to be more sensitive for high-grade CIN, and may further reduce the incidence of cervical cancer compared with cytology. However, they are associated with an increased frequency of positive tests without underlying CIN, and therefore increase the need for colposcopy and repeated testing. This problem will pose a major challenge for switching from cytology-based to HPV-based screening. The aim of this article is to discuss the role and the use of HPV tests and HPV genotyping in unvaccinated women.     

Impact of an HPV6/11/16/18 L1 virus-like particle vaccine on progression to cervical intraepithelial neoplasia in seropositive women with HPV16/18 infection

The impact of a human papillomavirus (HPV) vaccine on development of cervical intraepithelial neoplasia grade 2-3 or adenocarcinoma in situ (CIN2-3/AIS) in women with ongoing HPV16 or 18 infections prevaccination is reported. Seventeen thousand six-hundred and twenty-two women aged 16-26 were enrolled in 1 of 2 randomized, placebo-controlled, efficacy trials (Protocols 013 and 015). Vaccine or placebo was given at day 1, month 2 and 6. Women were tested for HPV6/11/16/18 DNA and antibodies at day 1. We focus on the subset of women who were seropositive and DNA positive to HPV16 or HPV18 prevaccination. Incidence is expressed as the number of women with an endpoint per 100 person-years-at-risk. In total, 419 vaccine and 446 placebo recipients were both seropositive and DNA positive to HPV16 or HPV18 prevaccination and had at least one follow-up visit. In Protocol 013, the incidence of HPV16/18-related CIN2-3/AIS among these women was 10.9 in the vaccine arm and 7.0 in the placebo arm (vaccine efficacy = -54.9; 95% CI: -181.7, 13.0). In Protocol 015, the incidence of HPV16/18-related CIN2-3/AIS was 5.5 in the vaccine arm and 6.2 in the placebo arm (vaccine efficacy = 12.2%; 95% CI: -29.8, 40.9). These data suggest HPV vaccination neither reduces nor enhances progression to HPV16/18-related high grade cervical lesions, and cervical cytology screening and corresponding management should continue as per local recommendations. Ultimately, population-based surveillance of vaccinated individuals beyond these clinical trials will be required to further address questions regarding the impact of vaccination in women exposed to vaccine HPV types before vaccination.     

Prior human papillomavirus‐16/18 AS04‐adjuvanted vaccination prevents recurrent high grade cervical intraepithelial neoplasia after definitive surgical therapy: Post‐hoc analysis from a randomized controlled trial

We evaluated the efficacy of the human papillomavirus (HPV)?16/18 AS04‐adjuvanted vaccine in preventing HPV‐related disease after surgery for cervical lesions in a post‐hoc analysis of the PApilloma TRIal against Cancer In young Adults (PATRICIA; NCT00122681). Healthy women aged 15–25 years were randomized (1:1) to receive vaccine or control at months 0, 1 and 6 and followed for 4 years. Women were enrolled regardless of their baseline HPV DNA status, HPV‐16/18 serostatus, or cytology, but excluded if they had previous or planned colposcopy. The primary and secondary endpoints of PATRICIA have been reported previously; the present post‐hoc analysis evaluated efficacy in a subset of women who underwent an excisional procedure for cervical lesions after vaccination. The main outcome was the incidence of subsequent HPV‐related cervical intraepithelial neoplasia grade 2 or greater (CIN2+) 60 days or more post‐surgery. Other outcomes included the incidence of HPV‐related CIN1+, and vulvar or vaginal intraepithelial neoplasia (VIN/VaIN) 60 days or more post‐surgery. Of the total vaccinated cohort of 18,644 women (vaccine = 9,319; control = 9,325), 454 (vaccine = 190, control = 264) underwent an excisional procedure during the trial. Efficacy 60 days or more post‐surgery for a first lesion, irrespective of HPV DNA results, was 88.2% (95% CI: 14.8, 99.7) against CIN2+ and 42.6% (?21.1, 74.1) against CIN1+. No VIN was reported and one woman in each group had VaIN2+ 60 days or more post‐surgery. Women who undergo surgical therapy for cervical lesions after vaccination with the HPV‐16/18 vaccine may continue to benefit from vaccination, with a reduced risk of developing subsequent CIN2+.     

Understanding long‐term protection of human papillomavirus vaccination against cervical carcinoma: Cancer registry‐based follow‐up

Phase III clinical trials of human papilloma virus (HPV) vaccination have shown ≥95% efficacy against HPV16/18 associated cervical intraepithelial neoplasia (CIN) Grade 2/3. Long‐term surveillance is, however, needed to determine the overall vaccine efficacy (VE) against CIN3 and invasive cervical carcinoma (ICC). During population‐based recruitment between September 2002 and March 2003, 1,749 16? to 17‐year old Finns participated in a multi‐national randomized Phase III HPV6/11/16/18 vaccine (FUTURE II) trial for the determination of VE against HPV16/18 positive CIN2/3. The passive follow‐up started at the country‐wide, population‐based Finnish Cancer Registry (FCR) six months after the active follow‐up and voluntary cross‐vaccination in April 2007. A cluster randomized, population‐based reference cohort of 15,744 unvaccinated, originally 18–19 year old Finns was established in two phases in 2003 and 2005 after the FUTURE II recruitment. We linked these cohorts with the FCR in 2007–2011 (HPV vaccine and placebo cohorts) and 2006–2010 and 2008–2012 (unvaccinated reference cohorts 1 and 2) to compare their incidences of CIN3 and ICC. The four years passive follow‐up resulted in 3,464, 3,444 and 62,876 person years for the HPV6/11/16/18, original placebo and reference cohorts, after excluding cases discovered during the clinical follow‐up and individuals not at risk. The numbers of CIN3 and ICC cases identified were 0 and 0, 3 and 0, 59 and 3 for the HPV6/11/16/18, placebo and the unvaccinated reference cohorts. The corresponding CIN3 incidence rates were 0/100,000 (95% confidence interval 0.0–106.5), 87.1/100,000 (95% CI 17.9–254.5) and 93.8/100,000 (95% CI 71.4–121), respectively. Long‐term surveillance up to 8 years (and longer) post vaccination of the HPV6/11/16/18 vaccine and placebo cohorts, and the unvaccinated reference cohort (not exposed to interventions) for the most stringent efficacy end‐points by passive cancer registry‐based follow‐up is feasible.     

Can we increase the cervical cancer screening interval with an HPV test for women living with HIV? Results of a cohort study from Maharashtra,India

We are reporting (a) updated incidence of cervical intraepithelial neoplasia (CIN) among women who did not have colposcopic or histopathological disease at baseline and (b) disease outcomes among women treated for CIN and their follow-up HPV status; in a cohort of women living with HIV (WHIV). The median overall follow-up was 3.5 years (IQR 2.8-4.3). The incidence of any CIN and that of CIN 2 or worse disease was 16.7 and 7.0 per 1000 person-years of observation (PYO), respectively. Compared with women who were HPV negative at baseline, women who cleared HPV infection had 23.95 times increased risk of incident CIN 2 or worse lesions (95% CI 2.40-661.07). Women with persistent HPV infection had 138.18 times increased risk of CIN 2 or worse lesions (95% CI 20.30-3300.22). Complete disease regression was observed in 65.6% of the HPV positive women with high-grade CIN and were treated with thermal ablation but HPV persistence was seen in 44.8% of those with high-grade disease. Among those who did not have any disease at baseline and were also HPV negative, about 87% (95% CI 83.79-89.48) women remained HPV negative during consecutive HPV test/s with the median interval of 3.5 years. Long-term surveillance of WHIV treated for any CIN is necessary for the prevention of cervical cancer among them. Our study provides an early indication that the currently recommended screening interval of 3 to 5 years among WHIV may be extended to at least 5 years among HPV negative women. Increasing the screening interval can be cost saving and improve scalability among WHIV to support WHO's cervical cancer elimination initiative.     

Cervical adenocarcinoma in situ: Human papillomavirus types and incidence trends in five states, 2008–2015

Primary prevention through the use of human papillomavirus (HPV) vaccination is expected to impact both cervical intraepithelial neoplasia (CIN) and adenocarcinoma in situ (AIS). While CIN is well described, less is known about the epidemiology of AIS, a rare cervical precancer. We identified AIS and CIN grade 3 (CIN3) cases through population-based surveillance, and analyzed data on HPV types and incidence trends overall, and among women screened for cervical cancer. From 2008 to 2015, 470 AIS and 6,587 CIN3 cases were identified. The median age of women with AIS was older than those with CIN3 (35 vs. 31 years; p < 0.01). HPV16 was the most frequently detected type in both AIS and CIN3 (57% in AIS; 58% in CIN3), whereas HPV18 was the second most common type in AIS and less common in CIN3 (38% vs. 5%; p < 0.01). AIS lesions were more likely than CIN3 lesions to be positive for high-risk types targeted by the bivalent and quadrivalent vaccines (HPV16/18, 92% vs. 63%; p < 0.01), and 9-valent vaccine (HPV16/18/31/33/45/52/58, 95% vs. 87%; p < 0.01). AIS incidence rates decreased significantly in the 21–24 year age group (annual percent change [APC] overall: −22.1%, 95% CI: −33.9 to −8.2; APC among screened: −16.1%, 95% CI: −28.8 to −1.2), but did not decrease significantly in any older age group. This report on the largest number of genotyped AIS cases to date suggests an important opportunity for vaccine prevention of AIS, and is the first to document a decline in AIS incidence rates among young women during the vaccine era.     

Human papillomavirus vaccine to prevent cervical intraepithelial neoplasia in Japan: A nationwide case‐control study

Cervical cancer remains among the most common cancers in women worldwide and can be prevented by vaccination. The Ministry of Health, Labour and Welfare of Japan suspended active recommendation of regular human papillomavirus (HPV) vaccines in 2013 because of various symptoms including chronic pain and motor impairment. This nationwide case‐control study from April 2013 to March 2017 targeted women aged 20‐24 years old at cervical screening. We compared HPV vaccination exposure between those with abnormal and normal cytology. Abnormal cytology was classified based on the results of histological test and we calculated the odds ratio (OR) and 95% confidence interval (CI) of the above endpoints and vaccination exposure using the conditional logistic regression model and estimated vaccine effectiveness using the formula (1 – OR) × 100. A total of 2483 cases and 12 296 controls (one‐to‐five matching) were eligible in 31 municipalities in Japan. The distribution of histological abnormalities among cases was 797 CIN1 (including dysplasia) (32.1%), 165 CIN2 (6.7%), 44 CIN3 (1.8%), and eight squamous cell carcinoma (SCC) (0.3%). The OR of HPV vaccination compared with no vaccination for abnormal cytology, CIN1+, CIN2+, and CIN3+ versus controls was 0.42 (95% CI, 0.34‐0.50), 0.42 (95% CI, 0.31‐0.58), 0.25 (95% CI, 0.12‐0.54), and 0.19 (95% CI, 0.03‐1.15), respectively, equating to a vaccine effectiveness of 58.5%, 57.9%, 74.8%, and 80.9%, respectively. Eight patients had SCC, none was vaccinated. This nationwide case‐control study in Japan demonstrated a substantial risk reduction in abnormal cytology and CIN among women who did versus those who did not receive HPV vaccination.     

Reduction in HPV16/18 prevalence among young women with high‐grade cervical lesions following the Japanese HPV vaccination program

The Japanese government began a human papillomavirus (HPV) vaccination program for girls aged 12‐16 years in 2010 but withdrew its recommendation in 2013 because of potential adverse effects, leading to drastically reduced vaccination uptake. To evaluate population‐level effects of HPV vaccination, women younger than 40 years of age newly diagnosed with cervical intraepithelial neoplasia grade 1‐3 (CIN1‐3), adenocarcinoma in situ (AIS), or invasive cervical cancer (ICC) have been registered at 21 participating institutes each year since 2012. A total of 7709 women were registered during 2012‐2017, of which 5045 were HPV genotyped. Declining trends in prevalence of vaccine types HPV16 and HPV18 during a 6‐year period were observed in CIN1 (50.0% to 0.0%, P_trend < .0001) and CIN2‐3/AIS (83.3% to 45.0%, P_trend = .07) only among women younger than 25 years of age. Overall, HPV vaccination reduced the proportion of HPV16/18‐attributable CIN2‐3/AIS from 47.7% to 33.0% (P = .003): from 43.5% to 12.5% as routine vaccination (P = .08) and from 47.8% to 36.7% as catch‐up vaccination (P = .04). The HPV16/18 prevalence in CIN2‐3/AIS cases was significantly reduced among female individuals who received their first vaccination at age 20 years or younger (P = .02). We could not evaluate vaccination effects on ICC owing to low incidence of ICC among women aged less than 25 years. We found HPV vaccination to be effective in protecting against HPV16/18‐positive CIN/AIS in Japan; however, our data did not support catch‐up vaccination for women older than 20 years. Older adolescents who skipped routine vaccination due to the government’s suspension of its vaccine recommendation could benefit from receiving catch‐up vaccination before age 20 years.     

A nationwide birth year-by-year analysis of effectiveness of HPV vaccine in Japan

In Japan, the age-adjusted incidence of cervical cancer has been increasing constantly and rapidly among younger women. We set out to accurately confirm the effectiveness of the HPV vaccine in Japan. Data were collected for women born in the fiscal year (FY) 1990 to 1997, who became eligible for their 20-y-old cervical cancer screening between the FY 2010 to 2017. The adjusted incidence of cervical intraepithelial neoplasia (CIN)1+ in women born in FY 1990 to 1993, that is those who reached the national vaccination target age prior to the introduction of publicly subsidized HPV vaccinations, referred here after as “the pre-introduction generation”, was 1.42% (242/17 040). The incidence in the “vaccination generation” (women born in FY 1994 to 1997, that is those who were heavily vaccinated as a group when they were of the nationally targeted age of 13-16) was 1.66% (135/8020). There was no significant difference between these incidence rates. However, our FY birth year-by-year analysis revealed that the incidence of CIN1+ was obviously lower than that predicted based on just the trend for CIN1+ seen in the pre-introduction generation. Our analysis revealed that the incidence of CIN3+ was obviously lower in the vaccination generation than in the pre-introduction generation (P = .0008). The incidence of CIN was already tending to increase in both the pre-introduction and vaccination generations. The changes in CIN incidence by individual birth FY must be examined to accurately determine the actual effects of the HPV vaccine for reducing mild cervical lesions.     

Human papillomavirus type-specific 18-month risk of high-grade cervical intraepithelial neoplasia in women with a normal or borderline/mildly dyskaryotic smear.

INTRODUCTION: High-risk human papillomavirus (hrHPV) DNA testing is an increasingly used instrument in cervical cancer prevention along cervical cytology. The inclusion of hrHPV testing in cervical screening requires efficient management as many hrHPV infections are transient. We investigated the potential value of hrHPV genotyping in normal and borderline/mildly dyskaryotic (BMD) smears. MATERIALS AND METHODS: From a screening population of 44,102 women in the Netherlands, we included hrHPV-positive women with a normal or BMD smear. We assessed the type-specific 18-month risk of high-grade cervical intraepithelial neoplasia (CIN). RESULTS: In hrHPV-positive women, 18-month risk of CIN grade 3 or invasive cancer (> or =CIN3) was 6% [95% confidence interval (95% CI), 4-9] after normal cytology and 20% (95% CI, 16-25) after BMD. If positive for HPV16, > or =CIN3 risks were 14% (95% CI, 9-21) and 37% (95% CI, 28-48), respectively. In the subset of hrHPV-positive women without HPV16, HPV18 was associated with an increased risk of high-grade CIN after normal cytology and HPV31 and HPV33 were associated with an increased risk, particularly after BMD. HPV16 and HPV18 were also associated with an increased risk of high-grade CIN in women with an hrHPV-positive normal baseline smear and a repeat normal smear at 6 months. DISCUSSION: HrHPV-positive women without type 16, 18, 31, or 33 had a relatively low risk of high-grade CIN. Among women with baseline normal cytology and among women with a baseline and repeat normal smear, HPV16/18-positive women showed an increased risk of high-grade CIN. This warrants more aggressive management of HPV16/18-positive women compared with other hrHPV-positive women.     

Differences in incidence and co‐occurrence of vaccine and nonvaccine human papillomavirus types in Finnish population before human papillomavirus mass vaccination suggest competitive advantage for HPV33

To understand likelihood of type replacement after vaccination against the high‐risk human papillomavirus (HPV) types, we evaluated competition of the seven most common genital HPV types in a population sample of unvaccinated, fertile‐aged Finnish women. First trimester sera from two consecutive pregnancies were retrieved from 3,183 Finnish women (mean age, 23.1 years) of whom 42.3% had antibodies to at least one HPV type (6/11/16/18/31/33/45) at the baseline. Antibody positivity to more than one HPV types by the second pregnancy was common among the baseline HPV seropositives. However, compared to baseline HPV‐seronegative women, significantly increased incidence rate ratios (IRRs), indicating an increased risk to seroconvert for another HPV type, were consistently noted only for HPV33 among baseline HPV16 or HPV18 antibody (ab)‐positive women: HPV_{16ab only → 16&33ab} IRR 2.9 [95% confidence interval (CI) 1.6–5.4] and HPV_{18ab only → 18&33ab} IRR 2.5 (95% CI 1.1–6.0), irrespectively of the presence of antibodies to other HPV types at baseline: HPV_{16ab → 16&33ab} IRR 3.2 (95% CI 2.0–5.2) and HPV_{18ab → 18&33ab} IRR 3.6 (95% CI 2.1–5.9). Our findings suggest a possible competitive advantage for HPV33 over other genital HPV types in the unvaccinated population. HPV33 should be monitored for type replacement after HPV mass vaccination.     

Urine testing to monitor the impact of HPV vaccination in Bhutan and Rwanda

Bhutan (2010) and Rwanda (2011) were the first countries in Asia and Africa to introduce national, primarily school‐based, human papillomavirus (HPV) vaccination programmes. These target 12 year‐old girls and initially included catch‐up campaigns (13–18 year‐olds in Bhutan and ninth school grade in Rwanda). In 2013, to obtain the earliest indicators of vaccine effectiveness, we performed two school‐based HPV urine surveys; 973 female students (median age: 19 years, 5th‐95th percentile: 18–22) were recruited in Bhutan and 912 (19 years, 17–20) in Rwanda. Participants self‐collected a first‐void urine sample using a validated protocol. HPV prevalence was obtained using two PCR assays that differ in sensitivity and type spectrum, namely GP5+/GP6+ and E7‐MPG. 92% students in Bhutan and 43% in Rwanda reported to have been vaccinated (median vaccination age = 16, 5th–95th: 14–18). HPV positivity in urine was significantly associated with sexual activity measures. In Rwanda, HPV6/11/16/18 prevalence was lower in vaccinated than in unvaccinated students (prevalence ratio, PR = 0.12, 95% confidence interval, CI: 0.03–0.51 by GP5+/GP6+, and 0.45, CI: 0.23–0.90 by E7‐MPG). For E7‐MPG, cross‐protection against 10 high‐risk types phylogenetically related to HPV16 or 18 was of borderline significance (PR = 0.68; 95% CI: 0.45–1.01). In Bhutan, HPV6/11/16/18 prevalence by GP5+/GP6+ was lower in vaccinated than in unvaccinated students but CIs were broad. In conclusion, our study supports the feasibility of urine surveys to monitor HPV vaccination and quantifies the effectiveness of the quadrivalent vaccine in women vaccinated after pre‐adolescence. Future similar surveys should detect increases in vaccine effectiveness if vaccination of 12 year‐olds continues.     

Human papillomavirus types in cervical dysplasia among young HPV-vaccinated women: Population-based nested case–control study

Human papillomavirus (HPV) vaccines protect against infections with the most oncogenic HPV types, cervical intraepithelial neoplasia (CIN) and cervical cancer. We investigated whether development of cervical intraepithelial neoplasia (CIN) lesions in HPV-vaccinated women is associated with vaccine-targeted HPV types or not. Linkage of the Swedish vaccination and cervical screening registries identified all females born 1980–2000 who had been HPV vaccinated before December 31, 2014 (n = 305,320) and had attended cervical screening in 2006–2018 (n = 79,491). We further selected women HPV vaccinated below 17 years of age and screened in the capital region (n = 5,874). Among those, 125 developed CIN and had a cervical cryopreserved sample available (42.5% of all eligible CIN cases). After 1:2 matching to disease-free HPV vaccinated controls (n = 242), samples were analyzed for HPV DNA and associations between HPV type and CIN diagnosis were estimated with conditional logistic regression. Vaccine-targeted HPV types were rare among both CIN cases (2.4% HPV16, 0.8% HPV18) and their matched controls (0.4% HPV16 and 18). No woman had HPV6 or 11. The CIN lesions were associated with the nonvaccine HPV types 31, 33, 42, 45, 51, 52, 56, 59 and 66. CIN lesions among young HPV vaccinated women are mostly attributable to infection with nonvaccine HPV types. The phenomenon may be important for surveillance and design of cervical cancer control strategies.     

A population-based study on the risk of cervical cancer and cervical intraepithelial neoplasia among grand multiparous women in Finland

Previous studies suggest that high parity increases the risk of cervical cancer. We studied the risk of cervical cancer (CC) and cervical intraepithelial neoplasia (CIN3) in a Finnish cohort of grand multiparous (GM) women (at least five children) with low prevalence of sexually transmitted infections (STI). The Finnish Cancer Registry data revealed 220 CC and 178 CIN3 cases among 86 978 GM women. Standardised incidence ratios (SIR) were calculated from the numbers of observed and expected cases. Interval analyses by parity, age at first birth and average birth interval were done using multivariate Poisson regression. Seroprevalence of human papillomavirus (HPV) 16 and Chlamydia trachomatis was tested among 561 GM women and 5703 women with 2-4 pregnancies. The incidence among GM women was slightly above the national average for squamous cell carcinoma of cervix uteri (SIR 1.21, 95% CI 1.05-1.40) and CIN3 (1.37, 95% CI 1.17-1.58), but lower for adenocarcinoma (SIR 0.77, 95% CI 0.52-1.10). The seroprevalence of HPV16 and Chlamydia trachomatis among GM women was lower than in the reference population, except among those women who had their child under age 19. Age under 20 years at first birth increased the risk of CC and CIN3 especially in premenopausal GM women, while increasing parity had no effect. The small relative risks of CC and CIN3 among GM women in our study as compared to studies from other countries can be explained by the exceptionally low prevalence of STIs in Finnish GM women. The observed SIRs between 1.2 and 1.4 should be interpreted to represent increased risk attributable to grand multiparity. The increased incidence of CC and CIN3 among young GM women suggests causal association to HPV 16 and Chlamydia trachomatis infections.     

Effectiveness of school-based and high-risk human papillomavirus vaccination programs against cervical dysplasia in Manitoba,Canada

The effectiveness of a vaccination program is influenced by its design and implementation details and by the target population characteristics. Using routinely collected population-based individual-level data, we assessed the effectiveness (against cervical dysplasia) of Manitoba's quadrivalent human papillomavirus (qHPV) routine school-based vaccination program and a short-lived campaign that targeted women at high-risk of developing cervical cancer. Females ≥9 years old who received the qHPV vaccine in Manitoba (Canada) between September 1, 2006, and March 31, 2013 (N = 31,442) were matched on age and area of residence to up to three unvaccinated females. Cox proportional hazards models were used to estimate qHPV VE against high-grade (HSILs) and low-grade squamous intraepithelial lesions (LSILs) and atypical squamous cells of undetermined significance (ASCUS). Among 14–17-year-old participants who had Pap cytology after enrollment, the adjusted qHPV VE estimates were 30% (17–58%) and 36% (21–48%) against the detection of HSILs and LSILs, respectively. There was, however, no evidence of program effectiveness among females vaccinated at ≥18 years of age and among those with a history of abnormal cytology, who were mostly vaccinated as part of the high-risk program. Estimates of VE for females vaccinated in the school-based program are consistent with the expected benefits from qHPV vaccination. No similar benefits were detected among women vaccinated at an older age, and those with abnormal cytology, who were targeted by the high-risk program. Further efforts should be targeted at achieving higher vaccine coverage among preadolescents, prior to the initiation of sexual activity.