Induction of immune memory following administration of a prophylactic quadrivalent human papillomavirus (HPV) types 6/11/16/18 L1 virus-like particle (VLP) vaccine

BACKGROUND: The duration of protection afforded by vaccines represents a critical test of their utility as public health interventions. Some vaccines induce long-term immunity, while others require booster doses. Vaccines that induce long-term protection are usually characterized by the generation of immune memory. Recent trials of a quadrivalent (types 6, 11, 16, 18) human papillomavirus (HPV) vaccine have demonstrated high efficacy through 5 years of follow-up. We evaluated the extent to which the vaccine is able to generate HPV type-specific immune memory. METHODS: A total of 552, 16-23-year-old women were enrolled in a double-blind, placebo-controlled study. At enrollment, subjects were randomized in a 1:1 ratio to receive three-dose regimens of quadrivalent HPV vaccine or placebo with 3 years' follow-up. A subset of 241 subjects (n=114 in the quadrivalent HPV vaccine group and n=127 in the placebo group) underwent 2 further years of follow-up. All extension subjects received quadrivalent HPV vaccine at month 60 to examine the extent of immune memory in response to the primary vaccination series. RESULTS: Serum anti-HPV levels declined post-vaccination, but reached a plateau at month 24 that remained stable through month 60. Administration of a challenge dose of vaccine induced a classic anamnestic response, with anti-HPV levels 1 week post-challenge reaching levels observed 1 month following the completion of the three-dose primary series. At 1 month post-challenge, anti-HPV responses were higher than those observed 1-month post-dose 3. DISCUSSION: A three-dose regimen of quadrivalent HPV vaccine induces high efficacy and stable anti-HPV levels for at least 5 years. Vaccination also induces robust immune memory. These findings suggest that the efficacy of this vaccine will be long lasting.     

Immunologic responses following administration of a vaccine targeting human papillomavirus Types 6, 11, 16, and 18

Human papillomavirus (HPV) infection causes cervical cancer and genital warts. Young women (1106) were randomized to receive one of three formulations of a quadrivalent HPV (Types 6/11/16/18) L1 virus-like particle (VLP) vaccine or one of two placebo formulations. The goal was to assess vaccine safety and immunogenicity in baseline HPV 6/11/16 or 18-naïve and previously infected subjects. All three formulations were highly immunogenic. At Month 2 (postdose 1), among women with vaccine-type antibodies at baseline, vaccine-induced anti-HPV responses were ∼12- to 26-fold higher than those observed in baseline-naïve women, suggesting an anamnestic response. Following an initial, similar sized decline, anti-HPV responses plateaued and remained stable through end-of-study (3.0 years). No vaccine-related serious adverse experiences were reported.     

Evaluation on the persistence of anti-HPV immune responses to the quadrivalent HPV vaccine in Chinese females and males: Up to 3.5 years of follow-up

BackgroundThis was an extension study of a randomized, double-blind, placebo-controlled immunogenicity and safety study of the quadrivalent human papillomavirus (qHPV) (HPV 6, 11, 16, and 18) vaccine conducted in Chinese female subjects aged 9–45 years and male subjects aged 9–15 years. To investigate the persistence of anti-HPV 6, -11, -16, and -18 responses among Chinese subjects, subjects enrolled in the base study were followed up at around month 42 (approximately 3.5 years after vaccination).MethodsAmong 600 subjects enrolled in the base study, a total of 468 subjects consented for participation in the extension study. Anti-HPV 6, -11, -16, and -18 antibodies were detected by the competitive Luminex immunoassay (cLIA) and total IgG Luminex immunoassay (IgG LIA).ResultsAmong the female subjects who received the qHPV vaccine, the proportions of subjects remained seropositive were high with both the cLIA and IgG LIA for HPV type 6, 11, and 16 through approximately 42 months following the first dose vaccination. For HPV 18, the seropositivity rate remained high as 82.0% with the IgG LIA, while it decreased to 53.6% with the cLIA, which was similar to the findings observed in other studies. The seropositivity rates remained high at month 42 for all qHPV types with both the cLIA and IgG LIA among the male subjects.ConclusionsAdministration of a 3-dose regimen of qHPV vaccine induces durable anti-HPV 6, anti-HPV 11, anti-HPV 16, and anti-HPV 18 responses among Chinese subjects for at least 3.5 years after vaccination.ClinicalTrials.gov registry: NCT01427777     

Efficacy,duration of immunity and cross protection after HPV vaccination: A review of the evidence

The efficacy and immunogenicity of HPV vaccines has proven excellent in several phase 2 and phase 3 trials involving tens of thousand women. A decrease in antibody titres was observed in follow-up studies of vaccinees, with initial sharp decline reaching a plateau in the longer term. Only few subjects lost their antibodies during the 5–6 years after vaccination. However, no breakthrough disease occurred even in those subjects. The administration of a challenge dose of quadrivalent vaccine at month 60 of follow-up resulted in a strong anamnestic response. The mechanism by which vaccination confers protection and the reasons for continuing vaccine efficacy remain to be elucidated. The same applies to the possibility of inducing an anamnestic response following viral challenge via genital mucosa.Data strongly suggest that both vaccines can have a variable level of cross protection against HPV types genetically and antigenically-closely related to vaccine types. Demonstration of cross protection against combined endpoints (CIN2/3 and AIS) for combined HPV types, and, as a single type, for HPV-31, has been reached for the quadrivalent vaccine, and there is evidence of cross protection against HPV 31 and 45 persistent infections (as single types) for the bivalent vaccine.Assays used for antibody detection were different for the two vaccines, and standardisation of methods for anti-HPV L1 protein detection is presently underway. The possibility to use universally accepted tests for antibody measurement would make comparison between vaccines and among different studies much easier.     

Immunogenicity and safety of the 9-valent HPV vaccine in men

ObjectivesThis study was designed to evaluate the immunogenicity and tolerability of a prophylactic 9-valent HPV (types 6/11/16/18/31/33/45/52/58) VLP (9vHPV) vaccine in young men 16–26 years of age in comparison to young women 16–26 years of age (the population that was used to establish 9vHPV vaccine efficacy). Safety and immunogenicity data from this study will be used to bridge 9vHPV vaccine efficacy findings in 16–26 year old women to 16–26 year old men.MethodsThis study enrolled 1106 heterosexual men (HM) and 1101 women who had not yet received HPV vaccination. In addition, 313 men having sex with men (MSM) were enrolled and were evaluated separately for immunogenicity because previous results showed that antibody responses to quadrivalent HPV (types 6/11/16/18) VLP (qHPV) vaccine were lower in MSM than in HM. All subjects were administered a 3-dose regimen (Day 1, Month 2, Month 6) of 9vHPV vaccine. Serum samples were collected for anti-HPV assays. Safety information was collected for ∼12 months.ResultsThe geometric mean titers (GMTs) for HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58 for HM were non-inferior to those of women at Month 7. For all vaccine HPV types, Month 7 GMTs were numerically lower in MSM than in HM. Over 99.5% of subjects were seropositive at Month 7 for each vaccine HPV type. Administration of 9vHPV vaccine to both 16–26 year old men and women was generally well tolerated.ConclusionsThese results support bridging the efficacy findings with 9vHPV vaccine in young women 16–26 years of age to men 16–26 years of age.     

A phase III clinical study to compare the immunogenicity and safety of the 9-valent and quadrivalent HPV vaccines in men

BackgroundA nine-valent human papilloma virus (9vHPV) vaccine has been developed to prevent infections and diseases related to HPV 6/11/16/18 (as per the licensed quadrivalent HPV (qHPV) vaccine) as well as to five additional oncogenic HPV types (HPV 31/33/45/52/58). The 9vHPV vaccine has the potential to prevent 90% of cervical cancers, HPV-related anal, vaginal and vulval cancers and anogenital warts. We compared the immunogenicity and safety of the 9vHPV vaccine versus the qHPV vaccine in 16–26-year-old men.MethodsParticipants (N = 500) were randomised to receive 9vHPV or qHPV vaccines on day 1, month 2 and month 6. Serology testing was performed on day 1 and month 7. HPV type-specific antibody titres (anti-HPV 6/11/16/18/31/33/45/52/58) were determined by competitive Luminex immunoassay and expressed as geometric mean titres and seroconversion rates. Vaccine safety was also assessed.ResultsThe HPV 6/11/16/18 immune responses elicited by the 9vHPV vaccine were comparable with those elicited by the qHPV vaccine. All participants receiving the 9vHPV vaccine seroconverted for HPV 31/33/45/52/58. The 9vHPV and qHPV vaccines showed comparable safety profiles.ConclusionsIn addition to immune responses to HPV 31/33/45/52/58, a three-dose regimen of the 9vHPV vaccine elicited a similar immune response to HPV 6/11/16/18 when compared with the qHPV vaccine in men aged 16–26 years. The safety profile was also similar for the two vaccines. The results from this study support extending the efficacy findings with qHPV vaccine to 9vHPV vaccine in men aged 16–26 years.NCT02114385     

Evaluation of immune response to single dose of quadrivalent HPV vaccine at 10-year post-vaccination

BackgroundThe recent World Health Organization recommendation supporting single-dose of HPV vaccine will significantly reduce programmatic cost, mitigate the supply shortage, and simplify logistics, thus allowing more low- and middle-income countries to introduce the vaccine. From a programmatic perspective the durability of protection offered by a single-dose will be a key consideration. The primary objectives of the present study were to determine whether recipients of a single-dose of quadrivalent HPV vaccine had sustained immune response against targeted HPV types (HPV 6,11,16,18) at 10 years post-vaccination and whether this response was superior to the natural antibody titres observed in unvaccinated women.MethodsParticipants received at age 10–18 years either one, two or three doses of the quadrivalent HPV vaccine. Serology samples were obtained at different timepoints up to 10 years after vaccination from a convenience sample of vaccinated participants and from age-matched unvaccinated women at one timepoint. The evolution of the binding and neutralizing antibody response was presented by dose received. 10-year durability of immune responses induced by a single-dose was compared to that after three doses of the vaccine and in unvaccinated married women.ResultsThe dynamics of antibody response among the single-dose recipients observed over 120 months show stabilized levels 18 months after vaccination for all four HPV types. Although the HPV type-specific (binding or neutralizing) antibody titres after a single-dose were significantly inferior to those after three doses of the vaccine (lower bounds of GMT ratios < 0.5), they were all significantly higher than those observed in unvaccinated women following natural infections (GMT ratios: 2.05 to 4.04-fold higher). The results correlate well with the high vaccine efficacy of single-dose against persistent HPV 16/18 infections reported by us earlier at 10-years post-vaccination.ConclusionOur study demonstrates the high and durable immune response in single-dose recipients of HPV vaccine at 10-years post vaccination.     

Long-term immunogenicity of a quadrivalent human papillomavirus vaccine in systemic lupus erythematosus

ObjectivesTo evaluate the 5-year immunogenicity of a quadrivalent human papillomavirus (HPV) vaccine (GARDASIL) in patients with systemic lupus erythematosus (SLE).MethodsFemale SLE patients and controls, aged 18–35 years, who received GARDASIL in 2011 and sero-converted 12 months post-vaccination were followed for persistence of immunogenicity. Antibody measurement to HPV serotypes 6, 11, 16, 18 was repeated at 5 years. The rate of sero-reversion was compared between patients and controls, and factors associated with sero-reversion of the anti-HPV antibodies were studied.Results50 SLE patients and 50 controls were vaccinated with GARDASIL. Among subjects who sero-converted at 1 year and consented for this study, antibodies to HPV serotypes 6, 11, 16 and 18 at 5 years were persistent in 24/27 (89%), 26/31 (84%), 32/34 (94%) and 24/25 (96%) of the SLE patients; and 32/33 (97%), 32/33 (97%), 32/32 (100%) and 23/24 (96%) of the controls, respectively. Antibody titers to HPV-6 and 16 were significantly lower in patients than controls. Seven (21%) SLE patients had sero-reversion of ≥1 anti-HPV antibodies. Sero-reverted patients experienced significantly more SLE flares, particularly renal, and had received significantly higher cumulative doses of prednisolone, mycophenolate mofetil and tacrolimus than those with persistent immunogenicity. The cumulative doses of prednisolone correlated inversely and significantly with the anti-HPV 6, 11, and 16 titers at 5 years.ConclusionsImmunogenicity of the quadrivalent HPV vaccine was retained in a high proportion of SLE patients at 5 year. Patients with more SLE renal flares and had received more immunosuppression were more likely to have sero-reversion of the anti-HPV antibodies.Clinical trial registration number: US ClinicalTrials.gov (NCT00911521 & NCT02477254).     

Prophylactic HPV vaccines: new interventions for cancer control

Human Papillomavirus (HPV) infection causes cervical cancer, a significant portion of anal, vulvar, vaginal, and oropharyngeal cancers, genital warts, and recurrent respiratory papillomatosis (RRP). HPV 16 and 18 cause 70-90% of HPV-related cancers whereas HPV 6 and 11 cause 90% of RRP and genital wart cases. Together these four types cause 30-50% of all cervical intraepithelial neoplasia such as those detected by Papinicalou screening. In June 2006, a quadrivalent HPV (6, 11, 16, 18) vaccine was licensed in the United States, and subsequently in the European Union (September 2006), both following expedited review. We describe the primary objectives of the quadrivalent HPV vaccine clinical trial program including studies in females aged 9-45 and males aged 9-26. Planned long-term efficacy and safety evaluations, as well as programs to evaluate vaccine impact on oropharyngeal cancer are also described.     

HPV vaccines to prevent cervical cancer and genital warts: an update

Cervical cancer is an important public health problem worldwide, and especially in developing countries. The link between cervical cancer and oncogenic human papillomavirus (HPV) infection has been clearly established. Furthermore, non-oncogenic HPV are responsible for the majority of genital warts. Two prophylactic HPV vaccines are available, which have the potential of considerably reducing HPV-related morbidity and mortality. Both vaccines are based on virus-like particles of the L1 capsid protein, and are highly efficacious and immunogenic if given before exposure to HPV, i.e. to adolescent girls between 9 and 13 years of age in a three-dose schedule. This review describes the immunology of natural HPV infections and the immune response evoked through vaccination. The current duration of protection is 8.4 years with the bivalent vaccine (HPV16/18) and 5 years with the quadrivalent vaccine (HPV6/11/16/18). Research is on-going to evaluate the efficacy of the current vaccines in a two-dose schedule, as compared to the recommended three-dose schedule. To increase the protection, the development and testing of a nine-valent prophylactic HPV vaccine (HPV6/11/16/18/31/33/45/52/58) is being undertaken. Research is also directed towards therapeutic vaccines and the development of a prophylactic L2 vaccine.     

Safety and immunogenicity of a vaccine targeting human papillomavirus types 6, 11, 16 and 18: a randomized, double-blind, placebo-controlled trial in Chinese males and females

In this randomized, double-blind, placebo-controlled trial, 9-15 year old Chinese males (n=100) and 9-45 year old Chinese females (n=500) from Wuzhou, Guangxi, China were randomized (1:1) to receive either quadrivalent HPV vaccine or adjuvant-containing placebo. Blood samples were obtained at day 1 and one month post-dose 3 to determine the level of vaccine-induced antibodies. Among vaccine recipients, high antibody levels were observed for each of the four HPV types and seroconversion was >96%. The vaccine was generally well tolerated, with no vaccine-related serious adverse events. This study demonstrated that the quadrivalent HPV vaccine is highly immunogenic and generally well tolerated among Chinese males and females.     

Bivalent AS04-adjuvanted HPV vaccine provides optimal cancer prevention for HPV types not included in the vaccine

All available HPV vaccines contain oncogenic types 16 and 18, most often found in HPV-related cancers and precursor lesions, but they differ in their valence and adjuvant potency. The quadri- and nonavalent HPV vaccines both contain additional types 6 and 11, related to anogenital warts, while the nonavalent vaccine contains another five types that are less frequently found in cancers. The bivalent vaccine is adjuvanted by AS04. Phase-III randomised controlled trials and population-based studies on bi- and quadrivalent vaccines suggest that the two vaccines when administered to HPV-naive persons, are optimally effective in preventing cervical intra-epithelial neoplasia grade 3 or greater, caused by types 16 or 18 (specific protection). In addition, the bivalent vaccine, but not the quadrivalent vaccine, cross-protects against HPV types not contained in the vaccine. The advantage of the quadrivalent vaccine to provide additional protection against anogenital warts, should not be traded for a lower overall efficacy in preventing pre-cancerous lesions and eventually cancer.     

Human Papillomavirus neutralizing and cross-reactive antibodies induced in HIV-positive subjects after vaccination with quadrivalent and bivalent HPV vaccines

Ninety-one HIV-infected individuals (61 men and 30 women) were randomized to vaccination either with quadrivalent (Gardasil™) or bivalent (Cervarix™) HPV vaccine. Neutralizing and specific HPV-binding serum antibodies were measured at baseline and 12 months after the first vaccine dose. Presence of neutralizing and binding antibodies had good agreement (average Kappa for HPV types 6, 11, 16, 18, 31, 33 and 45 was 0.65). At baseline, 88% of subjects had antibodies against at least one genital HPV. Following vaccination with Cervarix™, all subjects became seropositive for HPV16 and 18. After Gardasil™ vaccination, 96% of subjects seroconverted for HPV16 and 73% for HPV18. Levels of HPV16-specific antibodies were <1 international unit (IU) in 87% of study subjects before vaccination but >10 IU in 85% of study subjects after vaccination. Antibodies against non-vaccine HPV types appeared after Gardasil™ vaccination for >50% of vaccinated females for HPV 31, 35 and 73 and for >50% of Cervarix™-vaccinated females for HPV 31, 33, 35, 45, 56 and 58. Cross-reactivity with non-genital HPV types was also detected. In conclusion, HIV-infected subjects responded to HPV vaccination with induction of neutralizing antibodies against both vaccine and non-vaccine types.     

Antibody responses to prophylactic quadrivalent human papillomavirus vaccine at 48 months among HIV-infected girls and boys ages 9–14 in Kenya,Africa

ObjectivesHIV infected children remain at increased risk of HPV associated malignancies as they initiate sexual activity. Though they mount a vigorous immune response to the quadrivalent human papillomavirus (QHPV-6, -11,-16, and -18; Gardasil®) vaccine, durability of the immune response is uncertain. We assessed antibody responses to HPV 6, -11, -16 and -18 for up to 48 months following administration of quadrivalent human papillomavirus vaccine in HIV-infected girls and boys ages 9–14 years in Kenya.DesignOf 178 girls and boys who had previously received three doses of the quadrivalent HPV vaccine, 176 enrolled into extended follow up for 4 years. HPV antibodies to -6, -11, -16 and -18 were measured at 24, 36 and 48 months after the first vaccine dose using the total immunoglobulin G immunoassay (IgG LIA). We evaluated the magnitude and trend in HPV vaccine response and the effect of plasma HIV-1 RNA on HPV vaccine response from month 24 to month 48 of follow up.ResultsAt re-enrollment, 24 months after initial vaccination, median age of participants was 14 years (range 11–17); 167 (95%) were receiving antiretroviral therapy and 110 (66%) had plasma HIV RNA < 40 copies/mL. The rate of HPV seropositivity at 48 months was 83% for HPV-6; 80% for HPV-11; 90% for HPV-16; and 77% for HPV-18. There was a plateau in mean log10 HPV-specific antibody titer between month 24 and 48. The mean log10 HPV-type specific antibody titer for children with undetectable HIV viral load (<40) at the time of vaccination consistently remained higher for the 48 months of follow up compared to children with detectable viral load.ConclusionChildren with HIV infection may retain long term antibody response following HPV immunization. Further work to define whether HIV-infected children are protected from HPV acquisition with low levels of HPV antibodies is needed.     

Systematic literature review of neutralizing antibody immune responses to non-vaccine targeted high-risk HPV types induced by the bivalent and the quadrivalent vaccines

IntroductionStudies on the cross-protective effect of HPV bivalent and quadrivalent vaccines demonstrated inconsistent findings against additional HPV types covered by the nonavalent vaccine. The objective of this study was to conduct a systematic literature review to assess the consistency and durability of the cross-protective neutralizing antibody immune responses of the currently licensed bivalent and quadrivalent vaccines to non-vaccine HPV types targeted by the nonavalent vaccine (HPV 6, 11, 31, 33, 45, 52, and 58).MethodsPubMed and EMBASE databases were searched from 2008 to 2019 to identify studies reporting antibody/immune response after vaccination with either the bivalent, quadrivalent, or nonavalent vaccine. Key outcomes were seroconversion, seropositivity or geometric mean titers against HPV types 6, 11, 31, 33, 45, 52, and 58.ResultsEighteen publications met inclusion criteria, reporting on 14 interventional and five observational studies. Across all studies, immune responses to non-vaccine high-risk HPV types after bivalent vaccination were higher than baseline or quadrivalent vaccine. Nonavalent vaccine elicited near total seroconversion to HPV types 31, 33, 45, 52, and 58, with seropositivity remaining near 100% up to 24 months post-dose 1. In contrast, bivalent and quadrivalent vaccination resulted in lower seroconversion levels for non-vaccine types, which waned over time.ConclusionsThe cross-protection antibody/immune response among participants having received all three doses of bivalent or quadrivalent vaccine is not comparable to the specific response elicited by HPV vaccine types. Even in cases where a statistically significant cross-reactive immunological response is reported, long-term data on the duration of the response beyond two years are very limited. Further, the lack of a standard for assays limits comparability of results between studies.     

Safety and immunogenicity of co-administered quadrivalent human papillomavirus (HPV)-6/11/16/18 L1 virus-like particle (VLP) and hepatitis B (HBV) vaccines

Adolescents and young adults are at high risk for human papillomavirus (HPV) and hepatitis B virus (HBV) infections, which are preventable by currently available, safe and effective, prophylactic vaccines. However, development of a combined immunization strategy may lead to better compliance for these vaccines, thereby contributing to the overall goal of protection against these diseases. This study assessed the safety and immunogenicity of co-administered quadrivalent HPV-6/11/16/18 L1 VLP and HBV vaccines in women (n=1877) aged 16-23 years. Co-administration of HPV and HBV vaccines induced robust anti-HPV-6, HPV-11, HPV-16, HPV-18 geometric mean titers (GMTs) and > or =99% seroconversion rates (Month 7) that were both non-inferior (p<0.001) to those induced by HPV vaccine alone. High Month 7 anti-HBs GMTs were also observed following concomitant vaccination. These GMTs were lower compared to those induced by the HBV vaccine itself; however, >96% of subjects achieved an anti-HBs seroprotection level of > or =10 mIU/mL that was non-inferior (p<0.001) to that of HBV vaccine alone. Overall, co-administered and individual vaccines were generally well-tolerated and did not interfere with the immune response of either vaccine (ClinicalTrials.gov number, NCT00092521).     

Enhanced humoral and memory B cellular immunity using HPV16/18 L1 VLP vaccine formulated with the MPL/aluminium salt combination (AS04) compared to aluminium salt only

An effective virus-like particle (VLP) based prophylactic vaccine designed to protect against persistent infection with human papillomavirus (HPV) types 16 and 18 and subsequent lesion development will need to induce a strong humoral and cellular immune response capable of providing long-term protection. Our objective was to evaluate the ability of an HPV16/18 L1 VLP vaccine formulated with the AS04 adjuvant system (3-O-desacyl-4'-monophosphoryl lipid A (MPL) and aluminium salt) to induce an immune response of higher magnitude and persistence compared to a vaccine formulated with aluminium salt only. We demonstrated that MPL adsorbed onto aluminium salt retains its capacity to activate an innate immune response as assessed by the production of TNFalpha by human monocytes (U937). In addition, vaccination of mice, monkeys or human subjects with AS04 formulations induced higher total anti-L1 VLP16 and L1 VLP18 antibody responses (1.6-8.5-fold) than the aluminium salt only formulations. The enhanced antibody response induced by the AS04 vaccine formulation (1.6-4.1-fold) in monkeys and humans was shown to be targeted to functional neutralising L1 VLP16 and L1 VLP18 epitopes as assessed by V5/J4 specific ELISAs or HPV16 and HPV18 pseudo-neutralization assays. The enhanced immune profile observed with the AS04 formulation in terms of both total, V5/J4 specific and neutralizing antibodies was shown to persist for at least 3.5-year post-vaccination in human subjects. Finally, using the newly developed B cell ELISPOT assay we also demonstrated that the AS04 formulation elicited an increased frequency (2.2-5.2-fold) of HPV L1 VLP specific memory B cells when compared with the aluminium salt only formulations. These data strongly support the role of the AS04 adjuvant, which includes the immunostimulant MPL, in triggering a persistent vaccine-induced immune response of high quality.     

Systematic literature review of cross-protective effect of HPV vaccines based on data from randomized clinical trials and real-world evidence

BackgroundThe extent of cross-protection provided by currently licensed bivalent and quadrivalent HPV vaccines versus direct protection against HPV 31-, 33-, 45-, 52-, and 58-related disease is debated. A systematic literature review was conducted to establish the duration and magnitude of cross-protection in interventional and observational studies.MethodsPubMed and Embase databases were searched to identify randomized controlled trials (RCT) and observational studies published between 2008 and 2019 reporting on efficacy and effectiveness of HPV vaccines in women against non-vaccine types 31, 33, 45, 52, 58, and 6 and 11 (non-bivalent types). Key outcomes of interest were vaccine efficacy against 6- and 12-month persistent infection or genital lesions, and type-specific genital HPV prevalence or incidence. RCT data were analyzed for the according-to-protocol (bivalent vaccine) or negative-for-14-HPV-types (quadrivalent vaccine) efficacy cohorts.ResultsData from 23 RCTs and 33 observational studies evaluating cross-protection were extracted. RCTs assessed cross-protection in post-hoc analyses of small size subgroups. Among fully vaccinated, baseline HPV-naïve women, the bivalent vaccine showed statistically significant cross-protective efficacy, although with wide confidence intervals, against 6-month and 12-month persistent cervical infections and CIN2+ only consistently for HPV 31 and 45, with the highest effect observed for HPV 31 (range 64.6% [95% CI: 27.6 to 83.9] to 79.1% [97.7% CI: 27.6 to 95.9] for 6-month persistent infection; maximal follow-up 4.7 years). No cross-protection was shown in extended follow-up. The quadrivalent vaccine efficacy reached statistical significance for HPV 31 (46.2% [15.3–66.4]; follow-up: 3.6 years). Similarly, observational studies found consistently significant effectiveness only against HPV 31 and 45 with both vaccines.ConclusionsRCTs and observational studies show that cross-protection is inconsistent across non-vaccine HPV types and is largely driven by HPV 31 and 45. Furthermore, existing data suggest that it wanes over time; its long-term durability has not been established.     

Seropositivity to non-vaccine incorporated genotypes induced by the bivalent and quadrivalent HPV vaccines: A systematic review and meta-analysis

BackgroundHuman papillomavirus vaccines have demonstrated remarkable efficacy against persistent infection and disease associated with vaccine-incorporated genotypes and a degree of efficacy against some genetically related, non-vaccine-incorporated genotypes. The vaccines differ in the extent of cross-protection against these non-vaccine genotypes. Data supporting the role for neutralizing antibodies as a correlate or surrogate of cross-protection are lacking, as is a robust assessment of the seroconversion rates against these non-vaccine genotypes.MethodsWe performed a systematic review and meta-analysis of available data on vaccine-induced neutralizing antibody seropositivity to non-vaccine incorporated HPV genotypes.ResultsOf 304 articles screened, 9 were included in the analysis representing ca. 700 individuals. The pooled estimate for seropositivity against HPV31 for the bivalent vaccine (86%; 95%CI 78–91%) was higher than that for the quadrivalent vaccine (61%; 39–79%; p = 0.011). The pooled estimate for seropositivity against HPV45 for the bivalent vaccine (50%; 37–64%) was also higher than that for the quadrivalent vaccine (16%; 6–36%; p = 0.007). Seropositivity against HPV33, HPV52 and HPV58 were similar between the vaccines. Mean seropositivity rates across non-vaccine genotypes were positively associated with the corresponding vaccine efficacy data reported from vaccine trials.ConclusionsThese data improve our understanding of vaccine-induced functional antibody specificity against non-vaccine incorporated genotypes and may help to parameterize vaccine-impact models and improve patient management in a post-vaccine setting.     

Protecting our patients from HPV and HPV-related diseases: the role of vaccines

The clinical burden of disease resulting from human papillomavirus (HPV) infection is substantial and extends from genital warts to cytologic abnormalities to cervical, vaginal, and vulvar cancers and their associated precursor lesions. In addition, HPV is implicated in anal, penile, and head and neck cancers. Thus, HPV-related disease constitutes a significant burden for both men and women. Large phase 2 and 3 clinical trials with a quadrivalent preventive HPV vaccine (HPV 6/11/16/18) and phase 2 trials with a bivalent preventive HPV vaccine (HPV 16/18) have demonstrated that both products are highly efficacious in preventing type-specific HPV infections and HPV-related disease and are well tolerated. Nearly all recipients demonstrate a robust immunologic response that currently appears to be durable for 4 or more years. Immunogenicity data among girls 9 to 15 years of age were used to "bridge" efficacy data from quadrivalent HPV vaccine trials completed to date. In June 2006, the US Food and Drug Administration approved the quadrivalent HPV vaccine for use among females 9 to 26 years of age. The Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices has recommended the 3-dose series for girls 11 to 12 years of age, catch-up vaccination for girls and women 13 to 26 years of age, and permissive use as early as age 9. Computer models projecting the impact of these preventive HPV vaccines predict that they will be cost-effective and beneficial to the population; the use of preventive HPV vaccines will complement continued cytologic screening programs. Trials are under way to evaluate the duration of immune response as well as efficacy among men and women 27 years of age and older. Girls and women within the targeted age ranges should be offered vaccination to achieve the disease prevention potential of these vaccines.