Julia M.L. Brotherton

Early effect of the HPV vaccination programme on cervical abnormalities in Victoria, Australia: an ecological study

BACKGROUND Australia introduced a human papillomavirus (HPV) vaccination programme with the quadrivalent HPV vaccine for all women aged 12-26 years between 2007 and 2009. We analysed trends in cervical abnormalities in women in Victoria, Australia, before and after introduction of the vaccination programme. METHODS With data from the Victorian Cervical Cytology Registry between 2003 and 2009, we compared the incidence of histopathologically defined high-grade cervical abnormalities (HGAs, lesions coded as cervical intraepithelial neoplasia of grade 2 or worse or adenocarcinoma in situ; primary outcome) and low-grade cytological abnormalities (LGAs) in five age groups before (Jan 1, 2003, to March 31, 2007) and after (April 1, 2007, to Dec 31, 2009) the vaccination programme began. Binary comparisons between the two periods were done with Fishers exact test. Poisson piecewise regression analysis was used to compare incident rate trends. FINDINGS After the introduction of the vaccination programme, we recorded a decrease in the incidence of HGAs by 0·38% (95% CI 0·61-0·16) in girls younger than 18 years. This decrease was progressive and significantly different to the linear trend in incidence before introduction of the vaccination (incident rate ratio 1·14, 1·00-1·30, p=0·05). No similar temporal decline was recorded for LGAs or in older age groups. INTERPRETATION This is the first report of a decrease in incidence of HGAs within 3 years after the implementation of a population-wide HPV vaccination programme. Linkage between vaccination and screening registers is needed to confirm that this ecological observation is attributable to vaccination and to monitor participation in screening among vaccinated women. FUNDING None.

Population-level impact and herd effects following human papillomavirus vaccination programmes: a systematic review and meta-analysis.

BACKGROUND Human papillomavirus (HPV) vaccination programmes were first implemented in several countries worldwide in 2007. We did a systematic review and meta-analysis to assess the population-level consequences and herd effects after female HPV vaccination programmes, to verify whether or not the high efficacy reported in randomised controlled clinical trials are materialising in real-world situations. METHODS We searched the Medline and Embase databases (between Jan 1, 2007 and Feb 28, 2014) and conference abstracts for time-trend studies that analysed changes, between the pre-vaccination and post-vaccination periods, in the incidence or prevalence of at least one HPV-related endpoint: HPV infection, anogenital warts, and high-grade cervical lesions. We used random-effects models to derive pooled relative risk (RR) estimates. We stratified all analyses by age and sex. We did subgroup analyses by comparing studies according to vaccine type, vaccination coverage, and years since implementation of the vaccination programme. We assessed heterogeneity across studies using I(2) and χ(2) statistics and we did trends analysis to examine the dose-response association between HPV vaccination coverage and each study effect measure. FINDINGS We identified 20 eligible studies, which were all undertaken in nine high-income countries and represent more than 140 million person-years of follow-up. In countries with female vaccination coverage of at least 50%, HPV type 16 and 18 infections decreased significantly between the pre-vaccination and post-vaccination periods by 68% (RR 0·32, 95% CI 0·19-0·52) and anogenital warts decreased significantly by 61% (0·39, 0·22-0·71) in girls 13-19 years of age. Significant reductions were also recorded in HPV types 31, 33, and 45 in this age group of girls (RR 0·72, 95% CI 0·54-0·96), which suggests cross-protection. Additionally, significant reductions in anogenital warts were also reported in boys younger than 20 years of age (0·66 [95% CI 0·47-0·91]) and in women 20-39 years of age (0·68 [95% CI 0·51-0·89]), which suggests herd effects. In countries with female vaccination coverage lower than 50%, significant reductions in HPV types 16 and 18 infection (RR 0·50, 95% CI 0·34-0·74]) and in anogenital warts (0·86 [95% CI 0·79-0·94]) occurred in girls younger than 20 years of age, with no indication of cross-protection or herd effects. INTERPRETATION Our results are promising for the long-term population-level effects of HPV vaccination programmes. However, continued monitoring is essential to identify any signals of potential waning efficacy or type-replacement. FUNDING The Canadian Institutes of Health Research.

Fall in Human Papillomavirus Prevalence Following a National Vaccination Program

BACKGROUND In April 2007, Australia became the first country to introduce a national government-funded human papillomavirus (HPV) vaccination program. We evaluated the programs impact on genotype-specific HPV infection prevalence through a repeat survey of women attending clinical services. METHODS HPV genoprevalence in women aged 18-24 years attending family planning clinics in the prevaccine period (2005-2007) was compared with prevalence among women of the same age group in the postvaccine period (2010-2011). The same recruitment and testing strategies were utilized for both sets of samples, and comparisons were adjusted for potentially confounding variables. RESULTS The prevalence of vaccine HPV genotypes (6, 11, 16, and 18) was significantly lower in the postvaccine sample than in the prevaccine sample (6.7% vs 28.7%; P < .001), with lower prevalence observed in both vaccinated and unvaccinated women compared with the prevaccine population (5.0% [adjusted odds ratio, 0.11; 95% confidence interval, 0.06-0.21] and 15.8% [adjusted odds ratio, 0.42; 95% confidence interval, 0.19-0.93], respectively). A slightly lower prevalence of nonvaccine oncogenic HPV genotypes was also found in vaccinated women (30.8% vs 37.6%; adjusted odds ratio, 0.68; 95% confidence interval, 0.46-0.99). CONCLUSIONS Four years after the commencement of the Australian HPV vaccination program, a substantial decrease in vaccine-targeted genotypes is evident and should, in time, translate into reductions in HPV-related lesions.

Impact of a population-based HPV vaccination program on cervical abnormalities: a data linkage study

BackgroundAustralia was one of the first countries to introduce a publicly funded national human papillomavirus (HPV) vaccination program that commenced in April 2007, using the quadrivalent HPV vaccine targeting 12- to 13-year-old girls on an ongoing basis. Two-year catch-up programs were offered to 14- to 17- year-old girls in schools and 18- to 26-year-old women in community-based settings. We present data from the school-based program on population-level vaccine effectiveness against cervical abnormalities in Victoria, Australia.MethodsData for women age-eligible for the HPV vaccination program were linked between the Victorian Cervical Cytology Registry and the National HPV Vaccination Program Register to create a cohort of screening women who were either vaccinated or unvaccinated. Entry into the cohort was 1 April 2007 or at first Pap test for women not already screening. Vaccine effectiveness (VE) and hazard ratios (HR) for cervical abnormalities by vaccination status between 1 April 2007 and 31 December 2011 were calculated using proportional hazards regression.ResultsThe study included 14,085 unvaccinated and 24,871 vaccinated women attending screening who were eligible for vaccination at school, 85.0% of whom had received three doses. Detection rates of histologically confirmed high-grade (HG) cervical abnormalities and high-grade cytology (HGC) were significantly lower for vaccinated women (any dose) (HG 4.8 per 1,000 person-years, HGC 11.9 per 1,000 person-years) compared with unvaccinated women (HG 6.4 per 1,000 person-years, HGC 15.3 per 1,000 person-years) HR 0.72 (95% CI 0.58 to 0.91) and HR 0.75 (95% CI 0.65 to 0.87), respectively. The HR for low-grade (LG) cytological abnormalities was 0.76 (95% CI 0.72 to 0.80). VE adjusted a priori for age at first screening, socioeconomic status and remoteness index, for women who were completely vaccinated, was greatest for CIN3+/AIS at 47.5% (95% CI 22.7 to 64.4) and 36.4% (95% CI 9.8 to 55.1) for women who received any dose of vaccine, and was negatively associated with age. For women who received only one or two doses of vaccine, HRs for HG histology were not significantly different from 1.0, although the number of outcomes was small.ConclusionA population-based HPV vaccination program in schools significantly reduced cervical abnormalities for vaccinated women within five years of implementation, with the greatest vaccine effectiveness observed for the youngest women.

Assessment of herd immunity and cross-protection after a human papillomavirus vaccination programme in Australia: a repeat cross-sectional study

BACKGROUND After the introduction of a quadrivalent human papillomavirus (HPV) vaccination programme in Australia in April, 2007, we measured the prevalence of vaccine-targeted and closely related HPV types with the aim of assessing direct protection, cross-protection, and herd immunity. METHODS In this repeat cross-sectional study, we recruited women aged 18-24 years who attended Pap screening between October, 2005, and July, 2007, in three major metropolitan areas of Australia to form our prevaccine-implementation sample. For our postvaccine-implementation sample, we recruited women aged 18-24 years who attended Pap screening in the same three metropolitan areas from August, 2010, to November, 2012. We compared the crude prevalence of HPV genotypes in cervical specimens between the prevaccine and the postvaccine implementation groups, with vaccination status validated against the National HPV Vaccination Program Register. We estimated adjusted prevalence ratios using log linear regression. We estimated vaccine effectiveness both for vaccine-targeted HPV types (16, 18, 6, and 11) and non-vaccine but related HPV types (31, 33, and 45). FINDINGS 202 women were recruited into the prevaccine-implementation group, and 1058 were recruited into the postvaccine-implementation group. Crude prevalence of vaccine-targeted HPV genotypes was significantly lower in the postvaccine-implementation sample than in the prevaccine-implementation sample (58 [29%] of 202 vs 69 [7%] of 1058; p<0·0001). Compared with the prevaccine-implementation sample, adjusted prevalence ratios for vaccine-targeted HPV genotypes were 0·07 (95% CI 0·04-0·14; p<0·0001) in fully vaccinated women and 0·65 (0·43-0·96; p=0·03) in unvaccinated women, which suggests herd immunity. No significant declines were noted for non-vaccine-targeted HPV genotypes. However, within the postvaccine-implementation sample, adjusted vaccine effectiveness against vaccine-targeted HPV types for fully vaccinated women compared with unvaccinated women was 86% (95% CI 71-93), and was 58% (26-76) against non-vaccine-targeted but related genotypes (HPV 31, 33, and 45). INTERPRETATION 6 years after the initiation of the Australian HPV vaccination programme, we have detected a substantial fall in vaccine-targeted HPV genotypes in vaccinated women; a lower prevalence of vaccine-targeted types in unvaccinated women, suggesting herd immunity; and a possible indication of cross-protection against HPV types related to the vaccine-targeted types in vaccinated women. FUNDING Australian National Health and Medical Research Council and Cancer Council Victoria.

Head and neck cancer in Australia between 1982 and 2005 show increasing incidence of potentially HPV-associated oropharyngeal cancers

Background:Although tobacco- and alcohol-associated head and neck cancers are declining in the developed world, potentially human papillomavirus (HPV)-associated oropharnygeal cancers are increasing.Methods:We analysed oropharyngeal and oral cavity cancer rates in Australia in 1982–2005. Cancers from the oropharynx (base of tongue, tonsil and other specific oropharyngeal sites) were classified as potentially HPV associated (n=8844); cancers in other oral cavity and oropharyngeal sites not previously associated with HPV were classified as comparison (n=28 379).Results:In 2000–2005, an average of 219, 159 and 110 cancers of the tonsil, base of tongue and other oropharyngeal sites were diagnosed annually, with incidences of 1.09 (95% CI: 1.03, 1.15), 0.79 (95% CI: 0.74, 0.84) and 0.55 (95% CI: 0.50, 0.59) per 100 000, respectively. An average of 1242 comparison cancers were diagnosed annually (6.17 (95% CI: 6.03, 6.31) per 100 000). In 1982–2005, there were significant annual increases in tonsil (1.39% (95% CI: 0.88, 1.92%)) and base of tongue cancers in males (3.02% (95% CI: 2.27, 3.78%)) and base of tongue cancer in females (3.45% (95% CI: 2.21, 4.70%)). There was a significant decrease in comparison cancers in men (−1.69% (95% CI: −1.96, −1.42%)), but not in females.Conclusion:Potentially HPV-associated oropharyngeal cancer in Australia is increasing; the impact of HPV vaccination on these cancers should be monitored.

Effectiveness of quadrivalent human papillomavirus vaccine for the prevention of cervical abnormalities: case-control study nested within a population based screening programme in Australia.

Objective To measure the effectiveness of the quadrivalent human papillomavirus (HPV) vaccine against cervical abnormalities four years after implementation of a nationally funded vaccination programme in Queensland, Australia. Design Case-control analysis of linked administrative health datasets. Setting Queensland, Australia. Participants Women eligible for free vaccination (aged 12-26 years in 2007) and attending for their first cervical smear test between April 2007 and March 2011. High grade cases were women with histologically confirmed high grade cervical abnormalities (n=1062) and “other cases” were women with any other abnormality at cytology or histology (n=10 887). Controls were women with normal cytology (n=96 404). Main outcome measures Exposure odds ratio (ratio of odds of antecedent vaccination (one, two, or three vaccine doses compared with no doses) among cases compared with controls), vaccine effectiveness ((1−adjusted odds ratio)×100), and number needed to vaccinate to prevent one cervical abnormality at first screening round. We stratified by four age groups adjusted for follow-up time, year of birth, and measures of socioeconomic status and remoteness. The primary analysis concerned women whose first ever smear test defined their status as a case or a control. Results The adjusted odds ratio for exposure to three doses of HPV vaccine compared with no vaccine was 0.54 (95% confidence interval 0.43 to 0.67) for high grade cases and 0.66 (0.62 to 0.70) for other cases compared with controls with normal cytology, equating to vaccine effectiveness of 46% and 34%, respectively. The adjusted numbers needed to vaccinate were 125 (95% confidence interval 97 to 174) and 22 (19 to 25), respectively. The adjusted exposure odds ratios for two vaccine doses were 0.79 (95% confidence interval 0.64 to 0.98) for high grade cases and 0.79 (0.74 to 0.85) for other cases, equating to vaccine effectiveness of 21%. Conclusion The quadrivalent HPV vaccine conferred statistically significant protection against cervical abnormalities in young women who had not started screening before the implementation of the vaccination programme in Queensland, Australia.

EUROGIN 2011 roadmap on prevention and treatment of HPV-related disease

The EUROGIN 2011 roadmap reviews the current burden of human papillomavirus (HPV)‐related morbidity, as well as the evidence and potential practice recommendations regarding primary and secondary prevention and treatment of cancers and other disease associated with HPV infection. HPV infection causes ∼600,000 cases of cancer of the cervix, vulva, vagina, anus and oropharynx annually, as well as benign diseases such as genital warts and recurrent respiratory papillomatosis. Whereas the incidence of cervical cancer has been decreasing over recent decades, the incidence of anal and oropharyngeal carcinoma, for which there are no effective screening programs, has been rising over the last couple of decades. Randomized trials have demonstrated improved efficacy of HPV‐based compared to cytology‐based cervical cancer screening. Defining the best algorithms to triage HPV‐positive women, age ranges and screening intervals are priorities for pooled analyses and further research, whereas feasibility questions can be addressed through screening programs. HPV vaccination will reduce the burden of cervical precancer and probably also of invasive cervical and other HPV‐related disease in women. Recent trials demonstrated that prophylactic vaccination also protects against anogenital HPV infection, anogenital intraepithelial lesions and warts associated with vaccine types, in males; and anal HPV infection and anal intraepithelial neoplasia in MSM. HPV‐related oropharyngeal cancer could be treated less aggressively because of better survival compared to cancers of the oropharynx unrelated to HPV. Key findings in the field of cervical cancer prevention should now be translated in cost‐effective strategies, following an organized approach integrating primary and secondary prevention, according to scientific evidence but adapted to the local situation with particular attention to regions with the highest burden of disease.

Anaphylaxis following quadrivalent human papillomavirus vaccination

Background: In 2007, Australia implemented the National human papillomavirus (HPV) Vaccination Program, which provides quadrivalent HPV vaccine free to all women aged 12–26 years. Following notification of 7 presumptive cases of anaphylaxis in the state of New South Wales, Australia, we verified cases and compared the incidence of anaphylaxis following HPV vaccination to other vaccines in comparable settings. Methods: We contacted all patients with suspected anaphylaxis and obtained detailed histories from telephone interviews and a review of medical records. A multidisciplinary team determined whether each suspected case met the standardized Brighton definition. Some participants also received skin-prick allergy testing for common antigens and components of the HPV vaccine. Results: Of 12 suspected cases, 8 were classified as anaphylaxis. Of these, 4 participants had negative skin-prick test results for intradermal Gardasil. From the 269 680 HPV vaccine doses administered in schools, 7 cases of anaphylaxis were identified, which represents an incidence rate of 2.6 per 100 000 doses (95% CI 1.0–5.3 per 100 000). In comparison, the rate of identified anaphylaxis was 0.1 per 100 000 doses (95% CI 0.003–0.7) for conjugated meningococcal C vaccination in a 2003 school-based program. Interpretation: Based on the number of confirmed cases, the estimated rate of anaphylaxis following quadrivalent HPV vaccine was significantly higher than identified in comparable school-based delivery of other vaccines. However, overall rates were very low and managed appropriately with no serious sequelae.

Measuring human papillomavirus (HPV) vaccination coverage and the role of the National HPV Vaccination Program Register, Australia

Accurate estimates of HPV vaccination coverage are critical for determining the proportion of the target female population that is not protected by the vaccine, as well as for monitoring the performance of vaccine delivery programs. The implementation of an HPV vaccination register, either as part of an existing immunisation register or stand-alone, can add substantial benefits to an HPV vaccination program. In Australia, the National HPV Vaccination Program Register supports the HPV vaccination program by providing information to consumers and providers about incomplete courses as well as estimates of vaccination coverage by age and area. Future monitoring of vaccine effectiveness will be facilitated by cross-linking to Pap test registries.