Evaluation of the immunogenicity of the quadrivalent HPV vaccine using 2 versus 3 doses at month 21: An epidemiological surveillance mechanism for alternate vaccination schemes

Immunogenicity of 2 or 3 Doses of 9vHPV Vaccine in U.S. Female Individuals 15 to 26 Years of Age

BACKGROUND: Within the United States, a 9-valent human papillomavirus (9vHPV) vaccine (HPV-6/11/16/18/31/33/45/52/58) is recommended as a two-dose series among individuals 9 to 14 years of age and a three-dose series among those 15 to 26 years of age. Data comparing two versus three doses of 9vHPV vaccine among individuals 15 to 26 years of age are limited. METHODS: We report on an ongoing, single-blinded, randomized noninferiority trial of the 9vHPV vaccine among individuals 15 to 26 years of age in the United States. Participants were randomly assigned to a two-dose (0 and 6 months) or three-dose (0, 2, and 6 months) schedule. Blood draws to assess antibody titers were planned before the first vaccination and at 1 and 6 months after the final vaccination. The primary outcome was the rate of seroconversion at 1 month after final vaccination. The secondary outcome was the two-dose versus three-dose ratio of antibody geometric mean titers (GMTs) for each of the 9vHPV genotypes at 1 and 6 months after final vaccination. This interim analysis reports results of female participants at 1 month after final vaccination. RESULTS: Of 860 participants screened, 438 were enrolled and randomly assigned to the two-dose (n=217) or three-dose (n=221) group. At 1 month after the final vaccine dose, the seroconversion rate for each of the nine HPV genotypes in the vaccine was 100% among participants in the two-dose group and 99% in the three-dose group. The point estimates of the two-dose versus three-dose ratios of antibody GMTs for eight of the nine HPV genotypes were above unity; the ratio for HPV-45 was 0.86 (95% confidence interval [CI], 0.66 to 1.13). This was also the smallest value for the lower bound of the 95% CI for all nine ratios (ratios above 1 favor the two-dose schedule). No serious adverse events were observed. CONCLUSIONS: In this unplanned interim analysis of U.S. female participants 15 to 26 years of age, two doses of 9vHPV vaccine appear to elicit responses similar to three doses at 1 month postvaccination. We await final results at 6 months following the last vaccine dose. (ClinicalTrials.gov number, NCT03943875.)

Human Papillomavirus: Challenges and Opportunities for the Control of Cervical Cancer

Viruses are the most abundant and genetically diverse entities on the planet, infect all life forms and have evolved with their hosts. To date, 263 viral species have been identified that infect humans, of which only seven are considered type I oncogenic. Human papillomavirus (HPV) is the main virus associated with cancer and is responsible for practically all cases of cervical carcinoma. Screening tests for early detection have been available since the 1960s. Undoubtedly, the entailment between knowledge of HPV biology and the natural history of cervical cancer has contributed to the significant advances that have been made for its prevention since the 21^st century, with the development of prophylactic vaccines and improved screening strategies. Therefore, it is possible to eradicate invasive cervical cancer as a worldwide public health problem, as proposed by the WHO with the 90-70-90 initiative based on vaccination coverage, screening, and treatment, respectively. In addition, the emerging knowledge of viral biology generates opportunities that will contribute to strengthening prevention and treatment strategies in HPV-associated neoplasms.

Optimization of a protocol for the evaluation of antibody responses to human papillomavirus (HPV) vaccination in low-resource settings

Introduction

Available human papillomavirus (HPV) vaccines could have an important primary role in cervical cancer prevention once their long-term immunogenicity and safety are evaluated at the population level. The aim of this study was to optimize an assay to be used in evaluating the long-term durability of HPV vaccine response following a pilot vaccination of adolescent girls in Ghana.

Methods

A rapid, high-throughput, indirect enzyme-linked immunosorbent assay (ELISA) was optimized for the detection and quantitation of anti-HPV L1 (late expression protein: types 6, 11, 16 and 18) immunoglobulin G (IgG) in human serum (n = 89). The utility of the assay was demonstrated using serum collected from a cohort of pre-adolescent girls (n = 49) previously vaccinated with a quadrivalent vaccine and non-immune serum obtained from age-matched controls (n = 40).

Results

The assay showed good discrimination of antibody levels between cases and control sera: seroprevalence of anti-HPV IgG antibodies was significantly higher among vaccinated than unvaccinated girls for both HPV-16 (63.3% vs. 12.5%; p < 0.001) and HPV-18 (34.7% vs. 20.0%; p = 0.042), respectively. Thirty-six months after receiving the third dose of vaccine, significantly higher mean anti-HPV-16 (0.618 vs. 0.145), anti-HPV-18 (0.323 vs. 0.309), and anti-HPV-6 (1.371 vs. 0.981) antibody levels were measured, compared to unvaccinated girls (all p < 0.05). A correlation between optical density and antibody activity indicated assay sensitivity to increasing levels of antibody activity.

Conclusion

We have successfully optimized and implemented a robust and sensitive assay for the evaluation of antibody responses among immunized adolescent girls for monitoring future large-scale HPV vaccination studies in low-income settings. Our results demonstrated greater immunoglobulin G antibody activity within serum drawn from adolescent girls immunized 36 months prior.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12905-022-01821-y.

Reduction of HPV16/18 prevalence in young women after eight years of three- and two-dose vaccination schemes

BACKGROUND

Recommendations for human papillomavirus vaccination have relied on immunogenicity studies and efficacy results derived from adult women. Insufficient information exists regarding HPV effectiveness in vaccinated girls as they become sexually active, regardless of dose scheme. We aimed to compare the prevalence of high-risk HPV between unvaccinated and vaccinated young women eight years after immunization.

METHODS

After eight years, we recontacted women who received two-dose of bivalent or three-dose-either bivalent or quadrivalent-, HPV vaccine when aged 9-10 years-old as part of a clinical trial. Additionally, we recruited a contemporaneous unvaccinated woman group for comparison. Only those sexually active were included. High-risk HPV DNA was determined in urine samples and compared across groups.

RESULTS

The prevalence of HPV16/18 types was 6.8% (95 %CI 3.2-14.1%) in the unvaccinated (n = 6/88), 1.1% (95 %CI 0.2-5.8%) in the three-dose (n = 1/93), and 0.0% (95 %CI 0.0-7.0%) in the two-dose group (n = 0/51).

CONCLUSION

HPV vaccination, with two-dose of bivalent or three-dose schemes-either with the bivalent or quadrivalent vaccine-, was associated with a lower prevalence of HPV16/18 types eight years after primary immunization.

A prospective cohort study of immunogenicity of quadrivalent human papillomavirus vaccination among Alaska Native Children, Alaska, United States

OBJECTIVE

In the United States, HPV vaccination is routinely recommended at age 11 or 12 years; the series can be started at age 9. We conducted a cohort study to assess long-term immunogenicity of quadrivalent HPV vaccine (4vHPV) in an American Indian/Alaska Native (AI/AN) Indigenous population.

METHODS

During 2011-2014, we enrolled AI/AN girls and boys aged 9-14 years, who were vaccinated with a 3-dose series of 4vHPV. Serum specimens were collected at five time points: immediately prior to doses 2 and 3, and at one month, one year, and two years after series completion. Antibody testing was performed using a multiplex virus-like-particle-IgG ELISA for 4vHPV types (HPV 6/11/16/18).

RESULTS

Among 477 children (405 girls/72 boys) completing the 3-dose series, median age at enrollment was 11.2 years. Of the 477, 72 (15%) were tested before dose 2 and 70 (15%) before dose 3. Following series completion, 435 (91%) were tested at one month, 382 (80%) at one year, and 351 (74%) at two years. All tested participants had detectable antibody to 4vHPV types at all time points measured. Geometric mean concentrations (GMCs) for 4vHPV types at one month and two years post-series completion were 269.9 and 32.7 AU/ml for HPV6, 349.3 and 42.9 AU/ml for HPV11, 1240.2 and 168.3 IU/ml HPV16, and 493.2 and 52.2 IU/ml for HPV18. Among children tested after each dose, GMCs after doses 1 and 2 were 3.9 and 32.2 AU/ml for HPV6, 5.3 and 45.6 AU/ml for HPV11, 20.8 and 187.9 IU/ml for HPV16; and 6.6 and 49.7 IU/ml for HPV18. No serious adverse events were reported.

CONCLUSION

All AI/AN children developed antibodies to all 4vHPV types after vaccination. GMCs rose after each dose, then decreased to a plateau over the subsequent two years. This cohort will continue to be followed to determine duration of antibody response.

HPV vaccines: alternative dosage schedules

Introduction: The randomized control trials (RCTs) that resulted in licensure of HPV VLP vaccines used a traditional prime, prime-boost schedule for a subunit protein vaccine. These vaccines delivered predominantly to 9-14-year-old females with this schedule have been shown to be highly effective against vaccine HPV-type disease (CIN and genital warts) and infection. A two-dose prime-boost schedule is immunologically non-inferior to 3 doses in 9-14-year-olds and is currently widely adopted. However, even with a reduced dosage schedule, these vaccines are expensive to buy and expensive and logistically complex to deliver especially in low resource countries that bear the major burden of cervical cancer the most prevalent of HPV caused cancers.Areas covered: Observational studies and post hoc analysis of RCTs show that 1 dose, although immunologically inferior to 2 and 3 doses, is as effective at preventing persistent infection with vaccine HPV types at least for 7-10 years. To address the issue of alternative dosage schedules that include 1 dose either as a single dose or extended 1 + 1 with the second dose 3-5 years post-first dose are under investigation in RCTs.Expert opinion: Since, in the short term, vaccine supplies are constrained and will impact on the ability of countries to implement HPV vaccine programs: the challenges and opportunities of the alternative approaches in this scenario are discussed.

Uptake of the HPV vaccine among people with and without HIV, cisgender and transgender women and men who have sex with men and with women at two sexual health clinics in Mexico City

Our aim was to better understand Human Papillomavirus (HPV) vaccine acceptance among Mexican adults including people with and without HIV, cisgender men who have sex with men (MSM) or with women (MSW), cisgender and transgender women. A computer-assisted, self-administered questionnaire was completed by healthcare users and participants recruited through community organizations, and the first dose of the quadrivalent HPV vaccine was offered at no cost at a large sexual health clinic in Mexico City, from May to December 2018. Socio-demographic characteristics and factors associated with HPV vaccine acceptance were analyzed using logistic regression.The sample of 1915 participants included 1341 cisgender men (70.9%, 1247 MSM and 94 MSW), 396 (20.7%) cisgender women and 178 (9.3%) transwomen; 615 people (32.1%) were HIV positive. Uptake of the HPV vaccine was higher in men and transwomen (91.5% and 87%, respectively) than among cisgender women (81.8%; p < .001). Cisgender women (OR 0.43, 95%CI 0.30-0.61, p < .05) were less likely to accept HPV vaccination than men. Married/partnered people were less likely to accept HPV vaccination compared to those who were single (OR 0.70, 95%CI 0.51-0.97). People living with HIV were not significantly more likely to accept HPV vaccination (OR 1.7; 95%CI 0.86-1.61).HPV vaccine acceptance was high among adult Mexican study participants; it may be higher than among other Mexican adults given most of these individuals are engaged in care. Modifications will be needed in national and international recommendations on HPV vaccination in adults if healthcare personnel are to recommend the vaccine to the population groups studied.

The effect of a booster dose of HPV tetravalent vaccine after 51 months: implications for extended vaccination schedules

OBJECTIVE

To asses the non-inferiority between two differ- ent vaccination schedules one month after the administration of the third dose.

MATERIALS AND METHODS

We evaluated the anti-HPV 16/18 antibody titers induced by quadrivalent HPV vaccine administered using two different schedules in girls 9 to 10-year-old girls: a traditional (0-2-6) and an alterna- tive (0-6-50). Blood samples were collected at month 7, 21 and 51.

RESULTS

The antibody geometric mean titer ratios one month after the application of the third dose -month 51 for the alternative and month 7 for the traditional- were 1.55 for HPV16 (95%CI, 1.15-2.08) and 1.53 for HPV18 (95%CI, 1.12-2.09). The seropositive rate was above 99% in both groups.

CONCLUSIONS

The application of an alternative 3-dose schedule in 9 to 10-year-old girls induces a non-inferior immune response compared to the standard one month after the last dose. Further research is needed to understand the minimal number of doses and their timing to provide the best coverage for HPV infection.

Persistence of Immunity When Using Different Human Papillomavirus Vaccination Schedules and Booster-Dose Effects 5 Years After Primary Vaccination

Background

There are limited data regarding the duration of immunity induced by different human papillomavirus (HPV) vaccination schedules and the immunogenicity of a booster dose of both bivalent HPV vaccine (bHPV) or quadrivalent HPV vaccine (qHPV).

Methods

Follow-up of a nonrandomized clinical trial to evaluate the 5-year antibody persistence of the bHPV in girls (age, 9-10 years) and women (age, 18-24 years). Noninferiority of the 2-dose versus 3-dose schedule among girls was evaluated at months 54 (n = 639) and 64 (n = 990). Girls vaccinated with a 2-dose schedule of bHPV or qHPV received a booster dose of either vaccine at month 61. Immunogenicity was measured using a virus-like particle-based enzyme-linked immunosorbent assay. Geometric mean titers (GMTs) for HPV16/18 were estimated after stratification by vaccination schedule and age group.

Results

At months 54 and 64, the 2-dose schedule remained noninferior to the 3-dose schedule. GMTs remained above natural infection levels across all age groups up to 64 months. After the booster, anti-HPV16/18 GMTs increased exponentially with the same pattern, regardless of vaccine administered. No safety concerns were identified with the booster dose.

Conclusions

A 2-dose schedule is highly immunogenic in girls, suggesting a high immune memory. Thus, a booster dose is likely to be unprofitable, considering the low global immunization coverage.

Clinical Trials Registration

NCT01717118.

Persistence of immune response following bivalent HPV vaccination: A follow-up study among girls routinely vaccinated with a two-dose schedule

BACKGROUND

In this cohort study, we examined antibody levels and avidity after a two-dose schedule (0, 6 months) of the bivalent HPV-vaccine in girls routinely vaccinated in the Dutch HPV-vaccination program, up to 2 years following vaccination.

METHODS

A blood sample at 7, 12 and 24 months after the first dose and questionnaire data were collected (n = 56). HPV type-specific antibody concentrations (lU/ml) against seven types (HPV16/18/31/33/45/52/58) were assessed using a validated virus-like particles (VLP) multiplex immunoassay. Avidity was tested using a modification of this assay.

RESULTS

Seropositivity for vaccine types HPV 16 and 18 was 100% up to month 24, but declined for HPV-types 31/33/45/52/58, although not statistically significant for HPV45. All Geometric Mean Concentrations (GMCs) declined by months 12 and 24, but remained high for HPV16/18. Between month 7 and 12, GMCs declined more for other types. High avidity antibodies were induced up to 24 months for vaccine types (75%, 76-78% and 81-82% at months 7, 12 and 24, respectively), but for other types antibody avidity was 16-29% at month 7, 20-32% at month 12 and 19-32% at month 24.

CONCLUSIONS

GMCs declined over time for HPV-types 16/18/31/33/45/52/58, but remained high for vaccine-types HPV16/18 up to 24 months of follow-up. Antibody avidity was >75% for vaccine types but <35% for other HPV-types. Further follow-up of this cohort will provide insight into antibody and avidity kinetics over time.

Present challenges in cervical cancer prevention: Answers from cost-effectiveness analyses

Simulation models are commonly used to address important health policy issues that cannot be explored through experimental studies. These models are especially useful to determine a set of strategies that result in a good value for money (cost-effectiveness). Several mathematical models simulating the natural history of HPV and related diseases, especially cervical cancer, have been developed to calculate a relative effectiveness and cost-effectiveness of HPV vaccination and cervical cancer screening interventions. Virtually all cost-effectiveness analyses identify HPV vaccination programmes for preadolescent girls to be cost-effective, even for relatively low vaccination coverage rates. Routine vaccination of preadolescent girls is the primary target population for HPV vaccination as it shows to provide the greatest health impact. Cost-effectiveness analyses assessing other vaccine target groups are less conclusive. Adding additional age-cohorts would accelerate health benefits in some years, although cost-effectiveness becomes less favourable as age at vaccination increases. Including men in HPV vaccination programmes may be a less efficient strategy if done at the expense of female vaccination coverage for reducing the burden of HPV in the population. However, as the HPV vaccine price decreases, the cost-effectiveness of universal vaccination improves, becoming equally as efficient as female-only vaccination. Vaccine price is a decisive factor in the cost-effectiveness analyses. The lower the price, the greater the likelihood that vaccination groups other than the primary target would be considered cost-effective.

Early use of the HPV 2-dose vaccination schedule: Leveraging evidence to support policy for accelerated impact

Although human papillomavirus (HPV) vaccines were initially licensed based on efficacy after three-dose regimens in women aged 15-26 years, it was recognized early in clinical development that comparable immunogenicity could be obtained after just two doses when administered to younger girls. In both Canada and Mexico, public health authorities made the decision to administer two doses 6 months apart with a planned additional dose at 60 months, while simultaneously doing further study to determine if the third dose would confer meaningful additional benefit. This delayed third dose approach permitted a more cost-effective program with opportunities for improved compliance while minimizing injections and leaving open the opportunity to provide a full three-dose vaccination series. It required close cooperation across many governmental and civil society leadership bodies and real-time access to emerging data on HPV vaccine effectiveness. Although still limited, there is increasing evidence that even one-dose vaccination is sufficient to provide prolonged protection against HPV infection and associated diseases. Ongoing clinical trials and ecological studies are expected to consolidate existing data regarding one dose schedule use. However, to accelerate the preventive effect of HPV vaccination some jurisdictions, in particular those with limited resources may already consider the initiation of a one dose vaccination with the possibility of giving the second dose later in life if judged necessary. Such an approach would facilitate vaccination implementation and might permit larger catch-up vaccination programs in older girls (or as appropriate, girls and boys), thereby accelerating the impact on cervical cancer and other HPV-associated diseases.

Recommendations for cervical cancer prevention and control in Ghana: public education and human papillomavirus vaccination

Globally, cervical cancer is a major public health issue causing increasing morbidity and mortality especially in low- and middle-income countries where preventive and control measures are lacking. In Ghana, it is the most common cancer among women. Approaches to reduce the incidence and mortality of the disease in Ghana have had little success due to lack of accurate data on the disease among other factors, to inform policies on prevention, early detection, diagnosis and treatment. Additionally, the lack of clear commitment, policy direction and resources has hindered the scale-up of some of the initiatives implemented to curb the cervical cancer situation in Ghana. In this paper, we make recommendations on cervical cancer education and human papillomavirus vaccination. A collaborative approach is needed involving both private and government organizations, health professionals and the general public. Public education on cervical cancer and HPV vaccination needs to be delivered through a mixture of systems including both healthcare facilities and outreach programs, involving teachers, youth groups, community members and professional bodies. The vaccination of adolescents aged 10-14 years using the nonavalent HPV vaccine will be important in reducing the incidence and mortality of cervical cancer in Ghana. The integration of public education on cervical cancer prevention, HPV vaccination and screening programs into both medical and public health services is critical in achieving high coverage of these programs.

FUNDING

None.

Prophylactic vaccination against human papillomaviruses to prevent cervical cancer and its precursors

BACKGROUND

Persistent infection with high-risk human papillomaviruses (hrHPV) types is causally linked with the development of cervical precancer and cancer. HPV types 16 and 18 cause approximately 70% of cervical cancers worldwide.

OBJECTIVES

To evaluate the harms and protection of prophylactic human papillomaviruses (HPV) vaccines against cervical precancer and HPV16/18 infection in adolescent girls and women.

SEARCH METHODS

We searched MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL) and Embase (June 2017) for reports on effects from trials. We searched trial registries and company results' registers to identify unpublished data for mortality and serious adverse events.

SELECTION CRITERIA

Randomised controlled trials comparing efficacy and safety in females offered HPV vaccines with placebo (vaccine adjuvants or another control vaccine).

DATA COLLECTION AND ANALYSIS

We used Cochrane methodology and GRADE to rate the certainty of evidence for protection against cervical precancer (cervical intraepithelial neoplasia grade 2 and above [CIN2+], CIN grade 3 and above [CIN3+], and adenocarcinoma-in-situ [AIS]), and for harms. We distinguished between the effects of vaccines by participants' baseline HPV DNA status. The outcomes were precancer associated with vaccine HPV types and precancer irrespective of HPV type. Results are presented as risks in control and vaccination groups and risk ratios (RR) with 95% confidence intervals in brackets.

MAIN RESULTS

We included 26 trials (73,428 participants). Ten trials, with follow-up of 1.3 to 8 years, addressed protection against CIN/AIS. Vaccine safety was evaluated over a period of 6 months to 7 years in 23 studies. Studies were not large enough or of sufficient duration to evaluate cervical cancer outcomes. All but one of the trials was funded by the vaccine manufacturers. We judged most included trials to be at low risk of bias. Studies involved monovalent (N = 1), bivalent (N = 18), and quadrivalent vaccines (N = 7). Most women were under 26 years of age. Three trials recruited women aged 25 and over. We summarize the effects of vaccines in participants who had at least one immunisation.Efficacy endpoints by initial HPV DNA statushrHPV negativeHPV vaccines reduce CIN2+, CIN3+, AIS associated with HPV16/18 compared with placebo in adolescent girls and women aged 15 to 26. There is high-certainty evidence that vaccines lower CIN2+ from 164 to 2/10,000 (RR 0.01 (0 to 0.05)) and CIN3+ from 70 to 0/10,000 (RR 0.01 (0.00 to 0.10). There is moderate-certainty evidence that vaccines reduce the risk of AIS from 9 to 0/10,000 (RR 0.10 (0.01 to 0.82).HPV vaccines reduce the risk of any CIN2+ from 287 to 106/10,000 (RR 0.37 (0.25 to 0.55), high certainty) and probably reduce any AIS lesions from 10 to 0/10,000 (RR 0.1 (0.01 to 0.76), moderate certainty). The size of reduction in CIN3+ with vaccines differed between bivalent and quadrivalent vaccines (bivalent: RR 0.08 (0.03 to 0.23), high certainty; quadrivalent: RR 0.54 (0.36 to 0.82), moderate certainty). Data in older women were not available for this comparison.HPV16/18 negativeIn those aged 15 to 26 years, vaccines reduce CIN2+ associated with HPV16/18 from 113 to 6 /10,000 (RR 0.05 (0.03 to 0.10). In women 24 years or older the absolute and relative reduction in the risk of these lesions is smaller (from 45 to 14/10,000, (RR 0.30 (0.11 to 0.81), moderate certainty). HPV vaccines reduce the risk of CIN3+ and AIS associated with HPV16/18 in younger women (RR 0.05 (0.02 to 0.14), high certainty and RR 0.09 (0.01 to 0.72), moderate certainty, respectively). No trials in older women have measured these outcomes.Vaccines reduce any CIN2+ from 231 to 95/10,000, (RR 0.41 (0.32 to 0.52)) in younger women. No data are reported for more severe lesions.Regardless of HPV DNA statusIn younger women HPV vaccines reduce the risk of CIN2+ associated with HPV16/18 from 341 to 157/10,000 (RR 0.46 (0.37 to 0.57), high certainty). Similar reductions in risk were observed for CIN3+ associated with HPV16/18 (high certainty). The number of women with AIS associated with HPV16/18 is reduced from 14 to 5/10,000 with HPV vaccines (high certainty).HPV vaccines reduce any CIN2+ from 559 to 391/10,000 (RR 0.70 (0.58 to 0.85, high certainty) and any AIS from 17 to 5/10,000 (RR 0.32 (0.15 to 0.67), high certainty). The reduction in any CIN3+ differed by vaccine type (bivalent vaccine: RR 0.55 (0.43 to 0.71) and quadrivalent vaccine: RR 0.81 (0.69 to 0.96)).In women vaccinated at 24 to 45 years of age, there is moderate-certainty evidence that the risks of CIN2+ associated with HPV16/18 and any CIN2+ are similar between vaccinated and unvaccinated women (RR 0.74 (0.52 to 1.05) and RR 1.04 (0.83 to 1.30) respectively). No data are reported in this age group for CIN3+ or AIS.Adverse effectsThe risk of serious adverse events is similar between control and HPV vaccines in women of all ages (669 versus 656/10,000, RR 0.98 (0.92 to 1.05), high certainty). Mortality was 11/10,000 in control groups compared with 14/10,000 (9 to 22) with HPV vaccine (RR 1.29 [0.85 to 1.98]; low certainty). The number of deaths was low overall but there is a higher number of deaths in older women. No pattern in the cause or timing of death has been established.Pregnancy outcomesAmong those who became pregnant during the studies, we did not find an increased risk of miscarriage (1618 versus 1424/10,000, RR 0.88 (0.68 to 1.14), high certainty) or termination (931 versus 838/10,000 RR 0.90 (0.80 to 1.02), high certainty). The effects on congenital abnormalities and stillbirths are uncertain (RR 1.22 (0.88 to 1.69), moderate certainty and (RR 1.12 (0.68 to 1.83), moderate certainty, respectively).

AUTHORS' CONCLUSIONS

There is high-certainty evidence that HPV vaccines protect against cervical precancer in adolescent girls and young women aged 15 to 26. The effect is higher for lesions associated with HPV16/18 than for lesions irrespective of HPV type. The effect is greater in those who are negative for hrHPV or HPV16/18 DNA at enrolment than those unselected for HPV DNA status. There is moderate-certainty evidence that HPV vaccines reduce CIN2+ in older women who are HPV16/18 negative, but not when they are unselected by HPV DNA status.We did not find an increased risk of serious adverse effects. Although the number of deaths is low overall, there were more deaths among women older than 25 years who received the vaccine. The deaths reported in the studies have been judged not to be related to the vaccine. Increased risk of adverse pregnancy outcomes after HPV vaccination cannot be excluded, although the risk of miscarriage and termination are similar between trial arms. Long-term of follow-up is needed to monitor the impact on cervical cancer, occurrence of rare harms and pregnancy outcomes.

Antibody responses among adolescent females receiving two or three quadrivalent human papillomavirus vaccine doses at standard and prolonged intervals

BACKGROUND

The originally recommended dosing schedule, 0, 2, 6 months, for the 3-dose quadrivalent human papillomavirus vaccine (4vHPV) was often not followed, resulting in longer than recommended intervals between doses and interest in the effect of prolonged intervals. Recent two-dose recommendations require investigations into the effect of delaying dose 2.

METHODS

This multi-site, prospective study enrolled healthy 9-17 year old girls (n = 1321) on the day of or within 28 days following a third dose of 4vHPV vaccination. Antibody titers to 4vHPV types were measured at one and six months post-dose 3 from all participants and post-dose 2 from participants who were on time for dose 3. To compare antibody responses, participants were categorized into groups: second and third doses on time (control group); on-time dose 2, substantially late dose 3 (group 2); substantially late dose 2, on-time dose 3 (group 3); both doses substantially late (group 4). Analyses compared age-adjusted geometric mean titers (GMTs) at one-month and six-months post-dose 3, effect of delaying the second dose, and two versus three doses as well as post-dose 2 GMTs, stratified by age.

RESULTS

Compared to on-time dosing, one-month post-dose 3 GMTs were non-inferior in groups 2, 3, and 4 and were superior in group 2. Six month post-dose 3 GMTs were superior in groups 2, 3, and 4 for each genotype, except HPV 18 in group 3. Age-adjusted post does 2 titers were significantly lower than post-dose 3 titers when dose 2 was on time but were significantly higher when dose 2 was substantially late. Participants ≥15 years old had no difference in post-dose 2 titers compared to <15 year olds when dose 2 was substantially delayed.

CONCLUSIONS

Prolonged intervals between doses do not appear to diminish and may enhance antibody response to 4vHPV. ClinicalTrials.gov (NCT00524745).

Sustained Immunogenicity of 2-dose Human Papillomavirus 16/18 AS04-adjuvanted Vaccine Schedules in Girls Aged 9-14 Years: A Randomized Trial

Background.

We previously reported the noninferiority 1 month after the last dose of 2-dose human papillomavirus 16/18 AS04-adjuvanted (AS04-HPV-16/18) vaccine schedules at months 0 and 6 (2D_M0,6) and months 0 and 12 (2D_M0,12) in girls aged 9–14 years compared with a 3-dose schedule at months 0, 1, and 6 (3D_M0,1,6) in women aged 15–25 years. Here, we report the results at study end (month 36 [M36]).

Methods.

Girls were randomized 1:1 and received 2 vaccine doses either 6 months (2D_M0,6) or 12 months apart (2D_M0,12); women received 3 doses at months 0, 1, and 6 (3D_M0,1,6). Endpoints included noninferiority of HPV-16/18 antibodies for 2D_M0,6 versus 3D_M0,1,6; 2D_M0,12 versus 3D_M0,1,6; and 2D_M0,12 versus 2D_M0,6; and assessment of neutralizing antibodies, T cells, B cells, and safety.

Results.

At M36, the 2D_M0,6 and 2D_M0,12 schedules remained noninferior to the 3D_M0,1,6 schedule in terms of seroconversion rates and 3D/2D geometric mean titers for anti-HPV-16 and anti-HPV-18. All schedules elicited sustained immune responses up to M36.

Conclusions.

Both 2-dose schedules in young girls remained noninferior to the 3-dose schedule in women up to study conclusion at M36. The AS04-HPV-16/18 vaccine administered as a 2-dose schedule was immunogenic and well tolerated in young girls.

Timing of two versus three doses of quadrivalent HPV vaccine and associated effectiveness against condyloma in Sweden: a nationwide cohort study

OBJECTIVE

To assess incidence of condyloma after two doses of quadrivalent human papillomavirus (qHPV) vaccine, by time since first vaccine dose, in girls and women initiating vaccination before age 20 years.

DESIGN

Register-based nationwide open cohort study.

SETTING

Sweden.

PARTICIPANTS

Girls and women initiating qHPV vaccination before age 20 years between 2006 and 2012. The study cohort included 264 498 girls, of whom 72 042 had received two doses of qHPV vaccine and 185 456 had received all three doses.

MAIN OUTCOME MEASURE

Incidence rate ratios (IRRs) of condyloma estimated by time between first and second doses of qHPV in months (m) and age at vaccination, adjusted for attained age.

RESULTS

For girls first vaccinated with two doses before the age of 17 years, the IRR of condyloma for 0-3 months between the first and second doses was 1.96 (95% CI 1.43 to 2.68) as compared with the standard three-dose schedule. The IRRs were 1.27 (95% CI 0.63 to 2.58) and 4.36 (95% CI 2.05 to 9.28) after receipt of two doses with 4-7 months and 8+ months between doses, respectively. For women first vaccinated after the age of 17 years, vaccination with two doses of qHPV vaccine and 0-3 months between doses was associated with an IRR of 2.12 (95% CI 1.62 to 2.77). For an interval of 4-7 months between doses, the IRR did not statistically significantly differ to the standard three-dose schedule (IRR=0.81, 95% CI 0.36 to 1.84). For women with 8+ months between dose 1 and dose 2 the IRR was 3.16 (95% CI 1.40 to 7.14).

CONCLUSION

A two-dose schedule for qHPV vaccine with 4-7 months between the first and second doses may be as effective against condyloma in girls and women initiating vaccination under 20 years as a three-dose schedule. Results from this nationwide study support immunogenicity data from clinical trials.

Two-dose schedules for human papillomavirus vaccine: Systematic review and meta-analysis

Simpler schedules for human papillomavirus (HPV) vaccine delivery could improve vaccine coverage and the effectiveness of cervical cancer prevention. The objective of this study was to systematically review evidence about the effects of two-dose compared with three-dose schedules for human papillomavirus (HPV) vaccine and to describe the uptake of two-dose HPV vaccination schedules globally. We searched PubMed, the Cochrane Central Registry of Controlled Trials, trials registers, and manufacturers' databases from their earliest date to February 2016. We selected randomised controlled trials and controlled clinical trials that directly compared HPV vaccine schedules with two or three doses. We extracted data on immunological and clinical outcomes and used meta-analysis where appropriate. We also described the use of two-dose HPV vaccine schedules globally. We screened 1464 items and included seven eligible noninferiority trials in 11 countries. In randomised comparisons amongst adolescent girls (three trials), geometric mean concentrations (GMC) of antibodies against HPV16 and HPV18 were non-inferior or inconclusive, up to 24months after a two-dose compared with a three-dose schedule. One trial with a clinical outcome found no persistent HPV infections occurred after either two or three doses. In non-randomised comparisons, GMC were non-inferior or superior in adolescent girls receiving the two-dose schedule compared with women receiving the three-dose schedule for at least 21months after vaccination. By February 2017, 23 low and middle income and 25 high income countries had adopted a two-dose HPV vaccination schedule. A two-dose HPV vaccine schedule provides satisfactory immunological outcomes in adolescent girls, but uptake globally is limited, particularly in countries with the highest burden of cervical cancer.

Cancer screening in the United States, 2017: A review of current American Cancer Society guidelines and current issues in cancer screening

Answer questions and earn CME/CNE Each year, the American Cancer Society publishes a summary of its guidelines for early cancer detection, data and trends in cancer screening rates, and select issues related to cancer screening. In this issue of the journal, the authors summarize current American Cancer Society cancer screening guidelines, describe an update of their guideline for using human papillomavirus vaccination for cancer prevention, describe updates in US Preventive Services Task Force recommendations for breast and colorectal cancer screening, discuss interim findings from the UK Collaborative Trial on Ovarian Cancer Screening, and provide the latest data on utilization of cancer screening from the National Health Interview Survey. CA Cancer J Clin 2017;67:100-121. © 2017 American Cancer Society.

Health economic evaluation of Human Papillomavirus vaccines in women from Venezuela by a lifetime Markov cohort model

Background

Cervical cancer (CC) and genital warts (GW) are a significant public health issue in Venezuela. Our objective was to assess the cost-effectiveness of the two available vaccines, bivalent and quadrivalent, against Human Papillomavirus (HPV) in Venezuelan girls in order to inform decision-makers.

Methods

A previously published Markov cohort model, informed by the best available evidence, was adapted to the Venezuelan context to evaluate the effects of vaccination on health and healthcare costs from the perspective of the healthcare payer in an 11-year-old girls cohort of 264,489. Costs and quality-adjusted life years (QALYs) were discounted at 5%. Eight scenarios were analyzed to depict the cost-effectiveness under alternative vaccine prices, exchange rates and dosing schemes. Deterministic and probabilistic sensitivity analyses were performed.

Results

Compared to screening only, the bivalent and quadrivalent vaccines were cost-saving in all scenarios, avoiding 2,310 and 2,143 deaths, 4,781 and 4,431 CCs up to 18,459 GW for the quadrivalent vaccine and gaining 4,486 and 4,395 discounted QALYs respectively. For both vaccines, the main determinants of variations in the incremental costs-effectiveness ratio after running deterministic and probabilistic sensitivity analyses were transition probabilities, vaccine and cancer-treatment costs and HPV 16 and 18 distribution in CC cases. When comparing vaccines, none of them was consistently more cost-effective than the other. In sensitivity analyses, for these comparisons, the main determinants were GW incidence, the level of cross-protection and, for some scenarios, vaccines costs.

Conclusions

Immunization with the bivalent or quadrivalent HPV vaccines showed to be cost-saving or cost-effective in Venezuela, falling below the threshold of one Gross Domestic Product (GDP) per capita (104,404 VEF) per QALY gained. Deterministic and probabilistic sensitivity analyses confirmed the robustness of these results.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4064-7) contains supplementary material, which is available to authorized users.

Preventive vaccination against cervical cancer: Korean Society of Gynecologic Oncology Guideline

After human papillomavirus (HPV) vaccine guidelines published by Korean Society of Gynecologic Oncology (KSGO) in 2011, new studies have been published, leading to additional data regarding efficacy, safety, number of vaccination rounds, and ideal age of vaccine administration. We searched and reviewed the literatures focused on the efficacy of 2-dose schedule vaccination, the efficacy of 3-dose schedule vaccination in middle-aged women, the ideal age of 3-dose schedule vaccination, the safety of HPV preventive vaccine, and the ability of cross-protection of each HPV preventive vaccine. The KSGO has revised the previous guideline based on the results of the above studies.

An exploration of individual- and population-level impact of the 2-dose HPV vaccination schedule in pre-adolescent girls

Since 2014, several countries have implemented a 2-dose schedule for Human papillomavirus (HPV) vaccination. Licensure of the 2-dose schedule was based on non-inferiority results from immunobridging studies, comparing the antibody levels of the 2-dose schedule in young girls to those of the 3-dose schedule in young adults. Since licensure, additional data on antibody levels and other aspects of the immune response and clinical effectiveness have become available. This review will discuss the current outcomes on immunogenicity and effectiveness together with an exploration on the population impact of 2-dose schedules from a cost-effectiveness perspective. The 2-dose schedule has important benefits, such as easier logistics, reduced expenditure, potentially higher acceptance and fewer side effects. Policymakers and registration authorities should consider whether these benefits outweigh the likely differences on individual- and population-level impact between the 2- and 3-dose schedules.