Population-Level Effects of Human Papillomavirus Vaccination Programs on Infections with Nonvaccine Genotypes.
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SUBMITTER: Mesher D
PROVIDER: S-EPMC5038419 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description: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.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 ?(2) statistics and we did trends analysis to examine the dose-response association between HPV vaccination coverage and each study effect measure.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.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.The Canadian Institutes of Health Research.
| S-EPMC5144106 | biostudies-literature
Project description:BACKGROUND:More than 10 years have elapsed since human papillomavirus (HPV) vaccination was implemented. We did a systematic review and meta-analysis of the population-level impact of vaccinating girls and women against human papillomavirus on HPV infections, anogenital wart diagnoses, and cervical intraepithelial neoplasia grade 2+ (CIN2+) to summarise the most recent evidence about the effectiveness of HPV vaccines in real-world settings and to quantify the impact of multiple age-cohort vaccination. METHODS:In this updated systematic review and meta-analysis, we used the same search strategy as in our previous paper. We searched MEDLINE and Embase for studies published between Feb 1, 2014, and Oct 11, 2018. Studies were eligible if they compared the frequency (prevalence or incidence) of at least one HPV-related endpoint (genital HPV infections, anogenital wart diagnoses, or histologically confirmed CIN2+) between pre-vaccination and post-vaccination periods among the general population and if they used the same population sources and recruitment methods before and after vaccination. Our primary assessment was the relative risk (RR) comparing the frequency (prevalence or incidence) of HPV-related endpoints between the pre-vaccination and post-vaccination periods. We stratified all analyses by sex, age, and years since introduction of HPV vaccination. We used random-effects models to estimate pooled relative risks. FINDINGS:We identified 1702 potentially eligible articles for this systematic review and meta-analysis, and included 65 articles in 14 high-income countries: 23 for HPV infection, 29 for anogenital warts, and 13 for CIN2+. After 5-8 years of vaccination, the prevalence of HPV 16 and 18 decreased significantly by 83% (RR 0·17, 95% CI 0·11-0·25) among girls aged 13-19 years, and decreased significantly by 66% (RR 0·34, 95% CI 0·23-0·49) among women aged 20-24 years. The prevalence of HPV 31, 33, and 45 decreased significantly by 54% (RR 0·46, 95% CI 0·33-0·66) among girls aged 13-19 years. Anogenital wart diagnoses decreased significantly by 67% (RR 0·33, 95% CI 0·24-0·46) among girls aged 15-19 years, decreased significantly by 54% (RR 0·46, 95% CI 0.36-0.60) among women aged 20-24 years, and decreased significantly by 31% (RR 0·69, 95% CI 0·53-0·89) among women aged 25-29 years. Among boys aged 15-19 years anogenital wart diagnoses decreased significantly by 48% (RR 0·52, 95% CI 0·37-0·75) and among men aged 20-24 years they decreased significantly by 32% (RR 0·68, 95% CI 0·47-0·98). After 5-9 years of vaccination, CIN2+ decreased significantly by 51% (RR 0·49, 95% CI 0·42-0·58) among screened girls aged 15-19 years and decreased significantly by 31% (RR 0·69, 95% CI 0·57-0·84) among women aged 20-24 years. INTERPRETATION:This updated systematic review and meta-analysis includes data from 60 million individuals and up to 8 years of post-vaccination follow-up. Our results show compelling evidence of the substantial impact of HPV vaccination programmes on HPV infections and CIN2+ among girls and women, and on anogenital warts diagnoses among girls, women, boys, and men. Additionally, programmes with multi-cohort vaccination and high vaccination coverage had a greater direct impact and herd effects. FUNDING:WHO, Canadian Institutes of Health Research, Fonds de recherche du Québec - Santé.
| S-EPMC7316527 | biostudies-literature
Project description:ObjectivesTo characterize the immunogenicity of a quadrivalent human papillomavirus vaccine (QHPV) in human immunodeficiency virus (HIV)-infected children, we studied their immune responses to 3 or 4 doses.MethodsHIV-infected children aged 7-12 years with a CD4 cell percentage of ≥15% of lymphocytes, received 3 doses of QHPV with or without a fourth dose after 72 weeks. Type-specific and cross-reactive antibodies and cell-mediated immunity were measured.ResultsType-specific antibodies to HPV6, 11, and 16 were detected in 100% and ≥94% of children at 4 and 72 weeks, respectively, after the third QHPV dose. Corresponding numbers for HPV18 were 97% and 76%, respectively. A fourth QHPV dose increased seropositivity to ≥96% for all vaccine genotypes. Four weeks after the third QHPV dose, 67% of vaccinees seroconverted to HPV31, an HPV16-related genotype not in the vaccine; 69% and 39% of vaccinees developed mucosal HPV16 and 18 immunoglobulin G antibodies, respectively; and 60% and 52% of vaccinees developed cytotoxic T lymphocytes (CTLs) for HPV16 and 31, respectively.ConclusionsThree QHPV doses generated robust and persistent antibodies to HPV6, 11, and 16 but comparatively weaker responses to HPV18. A fourth dose increased antibodies against all vaccine genotypes in an anamnestic fashion. CTLs and mucosal antibodies against vaccine genotypes, as well as cross-reactive antibodies and CTL against nonvaccine genotypes, were detected.
| S-EPMC3529604 | biostudies-literature
Project description:BackgroundMortality rates from cervical cancer demonstrate deep inequality in health between richer and poorer populations. Over 310 000 women died of this preventable disease in 2018, mostly in low-income and middle-income countries (LMICs) where screening and treatment are beyond the capacity of health systems. Immunisation against human papillomavirus (HPV) offers a primary prevention strategy, but rates of vaccination uptake are unclear. Understanding coverage levels and factors affecting uptake can inform immunisation strategies.ObjectivesThe aim of this study is to evaluate the status of HPV vaccination coverage from nationally reported indicators and to estimate global coverage in a single year cohort of vaccine-eligible girls.DesignThis study provides quantitative population-level estimates of important global health indicators. Using data from the Global Cancer Observatory and WHO/UNICEF, incidence of and mortality from cervical cancer and HPV vaccination coverage are described for countries, categorised by income group. Characteristics of LMICs achieving high coverage are explored using selected development indicators from World Bank sources. Global HPV immunisation coverage is calculated and its impact on cervical cancer mortality estimated.ResultsIncidence and mortality for cervical cancer correlate with poverty. Whilst all WHO member states report high infant measles vaccination rates, fewer than half report on HPV vaccination. Even amongst high-income countries, coverage varies widely. In upper-middle-income countries, there is a trend for higher coverage with increased health spending per capita. Four LMICs report good coverage levels, all associated with external funding. Global HPV immunisation coverage for 2018 is estimated at 12.2%. Of the global cohort of 61 million 15-year-old girls in 2018, 7000 are likely to die from cervical cancer, almost all in LMICs.ConclusionsCountries in all income groups must devise strategies to achieve and maintain higher levels of HPV immunisation. For all but the richest, affordability remains a barrier.
| S-EPMC8413939 | biostudies-literature
Project description:IntroductionDemonstrating human papillomavirus vaccine impact is critical for informing guidelines to increase vaccination and decrease human papillomavirus‒related outcomes, particularly in states with suboptimal vaccination coverage, such as Tennessee. This study examines the trends in high-grade cervical lesion incidence among Tennessee Medicaid-enrolled women aged 18-39 years and the subset of women who were screened for cervical cancer.MethodsUsing a validated claims-based model to identify incident cervical intraepithelial neoplasia Grades 2 or 3 or adenocarcinoma in situ events, annual age group‒specific incidence rates from Tennessee Medicaid billing data, 2008-2018, were calculated. Significant trends were determined by Joinpoint. Analyses were conducted in 2020.ResultsFrom 2008 to 2018, high-grade cervical lesion incidence significantly declined in women aged 18-20 years (average annual percentage change= -31.9, 95% CI= -38.6, -24.6), 21-24 years (average annual percentage change= -12.9, 95% CI= -22.3, -2.4), and 25-29 years (average annual percentage change= -6.4, 95% CI= -8.1, -4.6). Among screened women, rates significantly declined for ages 18-20 years (average annual percentage change= -20.3, 95% CI= -25.3, -15.0), 21-24 years (average annual percentage change= -10.2, 95% CI= -12.6, -7.8), and 25-29 years (average annual percentage change= -2.6, 95% CI= -3.9, -1.2). Trends from 2008 to 2018 were stable for older age groups (30-34 and 35-39 years).ConclusionsResults show reductions in high-grade cervical lesion incidence among ages most likely to have benefited from the human papillomavirus vaccine. Declines among young, screened women suggest causes other than reduction in screening. Evidence of vaccine impact in populations with low-vaccination coverage, such as Tennessee, is promising.
| S-EPMC8863582 | biostudies-literature
Project description:BACKGROUND:No study has estimated the potential impact of Human Papillomavirus (HPV) vaccination in Puerto Rico, a population with considerable burden of HPV-related morbidities. We evaluated the health and economic impacts of implementing a vaccination strategy for females and males in Puerto Rico, with the quadrivalent HPV (HPV4) vaccine, under different vaccination scenarios. METHODS:We adapted a mathematical model which estimates the direct and indirect health benefits and costs of HPV4 vaccination in a dynamic population. The model compared three vaccination scenarios against screening only (no-vaccination) for three doses of HPV4 vaccine among individuals aged 11-15 years in Puerto Rico: 1) 34% for females and 13% for males (34%F/13%M), 2) 50% for females and 40% for males (50%F/40%M), and 3) 80% for female and 64% for male (80%F/64%M). Data specific to Puerto Rico was used. When not available, values from the United States were used. Input data consisted of demographic, behavioral, epidemiological, screening, and economic parameters. RESULTS:The model predicted decreases in: 1) HPV infection prevalence for females and males, 2) cervical intraepithelial neoplasia and cervical cancer incidence for females, 3) genital warts incidence for females and males, and 4) cervical cancer deaths among females, when various vaccination program scenarios were considered. In addition, when the vaccination percentage was increased in every scenario, the reduction was greater and began earlier. The analysis also evidenced an incremental cost effectiveness ratio (ICER) of $1,964 per quality-adjusted life year gained for the 80%F/64%M uptake scenario. CONCLUSIONS:HPV vaccine can prove its cost effectiveness and substantially reduce the burden and costs associated to various HPV-related conditions when targeted to the adequate population together with an organized HPV vaccination program.
| S-EPMC5708664 | biostudies-literature
Project description:Currently, two prophylactic human papillomavirus (HPV) vaccines targeting HPV 16 and 18 have been shown to be highly efficacious for preventing precursor lesions although the effectiveness of these vaccines in real-world clinical settings must still be determined. Toward this end, an ongoing statewide surveillance program was established in New Mexico to assess all aspects of cervical cancer preventive care. Given that the reduction in cervical cancer incidence is expected to take several decades to manifest, a systematic population-based measurement of HPV type-specific prevalence employing an age- and cytology-stratified sample of 47,617 women attending for cervical screening was conducted prior to widespread HPV vaccination. A well-validated polymerase chain reaction (PCR) method for 37 HPV genotypes was used to test liquid-based cytology specimens. The prevalence for any of the 37 HPV types was 27.3% overall with a maximum of 52% at age of 20 years followed by a rapid decline at older ages. The HPV 16 prevalences in women aged ? 20 years, 21-29 years or ? 30 years were 9.6, 6.5 and 1.8%, respectively. The combined prevalences of HPV 16 and 18 in these age groups were 12.0, 8.3 and 2.4%, respectively. HPV 16 and/or HPV 18 were detected in 54.5% of high-grade squamous intraepithelial (cytologic) lesions (HSIL) and in 25.0% of those with low-grade SIL (LSIL). These baseline data enable estimates of maximum HPV vaccine impact across time and provide critical reference measurements important to assessing clinical benefits and potential harms of HPV vaccination including increases in nonvaccine HPV types (i.e., type replacement).
| S-EPMC3852415 | biostudies-literature
Project description:BackgroundHuman papillomavirus (HPV) vaccination programs achieve substantial population-level impact, with effects extending beyond protection of vaccinated individuals. We assessed trends in HPV prevalence up to 8 years postvaccination among men and women in the Netherlands, where bivalent HPV vaccination, targeting HPV types 16/18, has been offered to (pre)adolescent girls since 2009 with moderate vaccination coverage.MethodsWe used data from the PASSYON study, a survey initiated in 2009 (prevaccination) and repeated biennially among 16- to 24-year-old visitors of sexual health centers. We studied genital HPV positivity from 2009 to 2017 among women, heterosexual men, and unvaccinated women using Poisson generalized estimating equation models, adjusted for individual- and population-level confounders. Trends were studied for 25 HPV types detected by the SPF10-LiPA25 platform.ResultsA total of 6354 women (64.7% self-reported unvaccinated) and 2414 heterosexual men were included. Percentual declines in vaccine types HPV-16/18 were observed for all women (12.6% per year [95% confidence interval {CI}, 10.6-14.5]), heterosexual men (13.0% per year [95% CI, 8.3-17.5]), and unvaccinated women (5.4% per year [95% CI, 2.9-7.8]). We observed significant declines in HPV-31 (all women and heterosexual men), HPV-45 (all women), and in all high-risk HPV types pooled (all women and heterosexual men). Significant increases were observed for HPV-56 (all women) and HPV-52 (unvaccinated women).ConclusionsOur results provide evidence for first-order herd effects among heterosexual men against HPV-16/18 and cross-protective types. Additionally, we show second-order herd effects against vaccine types among unvaccinated women. These results are promising regarding population-level and clinical impact of girls-only bivalent HPV vaccination in a country with moderate vaccine uptake.
| S-EPMC7935392 | biostudies-literature
Project description:We examined the concurrence of multiple human papillomavirus (HPV) infections in 47,617 women who underwent cervical screening in New Mexico between December 2007 and April 2009 using the LINEAR ARRAY HPV Genotyping Test (Roche Diagnostics, Indianapolis, Indiana), which detects 37 different types of HPV. Our primary goal was to examine the distributions of multiple HPV types with a special interest in negative interactions, which could signal the possibility of type replacement associated with a common niche if some HPV types were prevented by vaccination. Multiple infections were found to be more common than expected under independence, but this could largely be accounted for by a woman-specific latent heterogeneity parameter which was found to be dependent on age and cytological grade. While multiple infections were more common in young women and in those with abnormal cytology, greater heterogeneity was seen in older women and in those with normal cytology, possibly reflecting greater variability in exposure due to current or past HPV exposure or due to heterogeneity in related HPV reactivation or in immune responses to HPV infection or persistence. A negative interaction was found between HPV 16 and several other HPV types for women with abnormal cytology but not for those with normal cytology, suggesting that type replacement in women vaccinated against HPV 16 is unlikely to be an issue for the general population.
| S-EPMC4239798 | biostudies-literature
Project description:BACKGROUND:Cervical cancer was the fourth most common cancer among women worldwide in 2012 and was the eighth most common cancer in 2014 and the eighth greatest cause of female cancer deaths in Hong Kong in 2015. Human papillomavirus (HPV) vaccination has been clinically documented to have a high efficacy in reducing HPV-related cervical intraepithelial neoplasia incidence. Therefore, receiving vaccination is a crucial public health measure to reduce disease burden. Significant others, such as schools and schoolteachers, have prominent influence in shaping adolescents' health perceptions and behavior. Therefore, the perspective of schools and schoolteachers regarding vaccination can significantly influence students' acceptance and accessibility of the vaccine. However, few studies have analyzed the perceptions of schoolteachers toward HPV vaccination, and even fewer have concerned how schoolteachers' perceptions influence their schools' motivation in implementing school-based HPV vaccination programs. This study was thus conducted to fill this literature gap. METHODS:With a Chinese community as the field site of this study, a qualitative approach of five focus group interviews was conducted with 35 schoolteachers from five primary and eight secondary schools in Hong Kong between July 2014 and January 2015. Thematic content analysis was used for data analysis. RESULTS:Perceptual, institutional, student and parental, and collaborator barriers interacted to discourage the sampled schoolteachers from organizing school-based HPV vaccination programs. Lack of knowledge regarding HPV vaccination, perception of HPV vaccination as inappropriate given the students' age, violation of traditional cultural values, lack of perceived needs and perceived risk, opposition from schools, low priority of HPV vaccination over other health education topics, lack of government support, lack of interest from parents and students, and lack of confidence in implementing organizations, all were the mentioned barriers. CONCLUSIONS:The sampled schoolteachers were demotivated to organize school-based HPV vaccination programs because of their perceptions and various social and cultural factors. As significant influencers of adolescent students, schoolteachers and schools should receive more support and information on organizing school-based HPV vaccination programs in the future.
| S-EPMC6852998 | biostudies-literature