The levels of anti-HPV16/18 and anti-HPV31/33/35/45/52/58 antibodies among AS04-adjuvanted HPV16/18 vaccinated and non-vaccinated Ugandan girls aged 10-16 years

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.

Prevalence of vaccine and non-vaccine human papillomavirus types among women in Accra and Kumasi, Ghana: a cross-sectional study

BACKGROUND

Human Papillomavirus (HPV) infection is the main etiological factor for pre-invasive and invasive cervical cancer. HPV type-specific vaccination is being widely recommended to control the burden of disease, but the genotype-specific distribution of HPV may vary in different countries. The aim of the study was to determine the prevalence and distribution of HPV genotypes among women attending reproductive health services in Ghana, their associated risk factors, and to assess the potential coverage of identified HPV genotypes by three licensed vaccines among these women.

METHOD

Women presenting for reproductive health services in two regional hospitals in Accra and Kumasi from October 2014 to March 2015 were conveniently recruited into the study (n = 317). HPV-DNA detection and genotype identification were carried out by a nested multiplex PCR assay that combines degenerate E6/E7 consensus primers and type-specific primers for the detection and typing of eighteen HPV genotypes. Cytology was performed to screen women for cervical cancer lesions. Risk factors for HPV infection were analyzed by logistic regression. Statistical significance was accepted for p < 0.05.

RESULTS

The age of study participants ranged from 21 to 76 years. Among women positive for HPV, 35.0% were infected with high-risk HPV, 14.5% with probable high-risk HPV, and 17.0% with low-risk HPV. The prevalence of HPV 16/18 was 8.2%, HPV 6/11/16/18 was 9.1% and HPV 6/11/16/18/31/33/45/52/58 was 28.4%. The most prevalent among HR-HPV were types 52 (18.3%) and 58 (8.8%). HPV positivity may be associated with educational background (p < 0.001), age at first pregnancy (p = 0.028), and age at coitarche (p = 0.016).

CONCLUSIONS

Our study revealed a high prevalence of HR-HPV infection among women. The high prevalence of HR HPV indicates that multivalent vaccines will be useful for controlling HPV burden in general population contexts. The distribution of HPVs in this population suggests that of the three currently available vaccines the nonavalent vaccine, which protects against seven HPV types in addition to HPV 16 and 18, has the highest coverage of HPV infections among Ghanaian women. Healthcare officials planning to reduce the transmission of HPV and cervical cancer must consider the coverage of the nonavalent vaccine as an advantage.

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

INTRODUCTION

Studies 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).

METHODS

PubMed 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.

RESULTS

Eighteen 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.

CONCLUSIONS

The 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.

Natural and vaccine-induced B cell-derived systemic and mucosal humoral immunity to human papillomavirus

Introduction: Human papillomavirus (HPV) are the causative agent of mucosal neoplasia. Both cervical, anal and oropharyngeal cancers incidence is constantly increasing, making the HPV infection, a significant worldwide concern. Together, the CD8+ T cytotoxic cell-mediated response and the HPV-specific antibody response control most of the HPV infections before the development of cancers.Areas covered: We searched the MEDLINE and EMBASE databases and identified 228 eligible studies from 1987 to 2019 which examines both naturally acquired and vaccine induced humoral immunity against HPV infection in female and male subjects from worldwide origin. Herein, we synthesize current knowledge on the features of systemic and mucosal humoral immunity against HPV. We discuss the issues of the balance between the viral clearance or the escape to the host immune response, the differences between natural and vaccine-induced HPV-specific antibodies and their neutralizing capability. We also discuss the protection afforded after natural infection or following prophylactic vaccination.Expert opinion: Understanding the antibody response induced by HPV infection has led to the design of first-generation prophylactic vaccines. Now, prophylactic vaccination induces protective and long-lasting antibody response which would also strengthened the natural moderate humoral response in people previously exposed to the virus.

Priming effect of bivalent and quadrivalent vaccine for HPV 31/33/45/52: an exploratory analysis from two clinical trials

The main objective of this post hoc analysis is to compare the magnitude of the immune response to HPV31/33/45/52 and 58 after a dose of 9vHPV vaccine given to naïve (previously unvaccinated) subjects and subjects previously vaccinated with a dose of 2vHPV or 4vHPV vaccine. Results from two clinical trials conducted in the same region, in comparable populations and by the same research team were included in this analysis. In study A, a dose of 9vHPV was administered 6 months after a single dose of 2vHPV as well as to naïve subjects. In study B, a dose of 9vHPV was administered 36-96 months (mean 65 months) after a single dose of 4vHPV. Blood samples were collected just before and one month post-9vHPV vaccine administration. For both studies, antibody responses were measured using the same 9-plex virus-like particle based IgG ELISA (M9ELISA). One month after 9vHPV dose administration, all subjects were seropositive to HPV 31/33/45/52 and 58. Subjects who had previously received 2vHPV or 4vHPV had significantly higher (1.8-8.0-fold) GMTs than naive subjects for HPV31/33/45/52 types but not for HPV58. GMTs to HPV31/33/45/52 and 58 were not significantly different between subjects who received a 2vHPV or 4vHPV dose prior to 9vHPV. The strong anamnestic response to one dose of 9vHPV given as late as 3-8 years after a single dose of 2vHPV or 4vHPV vaccine indicates these vaccines induced priming to types only included in the 9vHPV vaccine.

Comprehensive Human Papillomavirus Genotyping in Cervical Squamous Cell Carcinomas and Its Relevance to Cervical Cancer Prevention in Malawian Women

PURPOSE

Cervical squamous cell carcinoma (SCC) continues to be a significant cause of cancer morbidity and is the third leading cause of cancer-related death in women worldwide. In sub-Saharan Africa, cervical cancer is not only the most common female cancer but also the leading cause of cancer-related deaths in women. Malawi, in particular, has the highest burden of cervical cancer. With the increasing use of human papillomavirus (HPV) vaccination, documenting the prevalent HPV types in those high-risk populations is necessary to both manage expectations of HPV vaccination and guide future vaccine development.

MATERIALS AND METHODS

In this study, we performed HPV typing on 474 cervical SCC samples and analyzed the potential impact of HPV vaccination in this population.

RESULTS

Ninety-seven percent of tumors were positive for at least one HPV type, and 54% harbored more than one HPV type. HPV 16 was the most common type (82%), followed by HPV 18 (34%), HPV 35 (24%), and HPV 31 (12%). A vaccine against HPV 16 and 18 would ideally prevent 53% of cervical SCC, and the nonavalent HPV vaccine (covering HPV 16, 18, 31, 33, 45, 52, and 58) would prevent 71% of cervical SCC in Malawi (assuming 100% vaccine efficacy). The main reason for a lack of coverage was high prevalence of HPV 35, which was also present as a single infection in a small subset of patients.

CONCLUSION

Although any HPV vaccination in this population would likely prevent a significant proportion of cervical cancer, the nonavalent vaccine would provide better coverage. Furthermore, investigation of the role of HPV 35 in this population, including possible cross-protection with other HPV types, should be pursued.

Vaccines against human papillomavirus in low and middle income countries: a review of safety, immunogenicity and efficacy

Currently, there is limited data on the immunogenicity and efficacy of human papillomavirus vaccines in Low and Middle income countries (LMIC). The review aims to summarize the current status from published HPV vaccine safety, immunogenicity and efficacy studies in low and middle income countries (LMIC). Electronic databases (PubMed/MEDLINE and HINARI) were searched for peer reviewed English language articles on HPV vaccination in LMIC that have so far been published from 1st January 2006 up to 30th January 2015. Eligible studies were included if they had used the bivalent (bHPV) or quadrivalent HPV (qHPV) vaccines in a LMIC and investigated safety, immunogenicity and/or efficacy. The main findings were extracted and summarized. A total of fourteen HPV vaccine studies assessing safety, Immunogenicity and efficacy of the bivalent or quadrivalent vaccines in LMIC were included. There are only ten published clinical trials where a LMIC has participated. There was no published study so far that assessed efficacy of the HPV vaccines in Sub-Saharan Africa. From these studies, vaccine induced immune response was comparable to that from results of HICs for all age groups. Studies assessing HPV vaccine efficacy of the bivalent or quadrivalent vaccine within LMIC were largely missing. Only three studies were found where a LMIC was part of a multi center clinical trial. In all the studies, there were no vaccine related serious adverse events. The findings from the only study that investigated less than three doses of the bivalent HPV-16/18 vaccine suggest that even with less than three doses, antibody levels were still comparable with older women where efficacy has been proven. The few studies from LMIC in this review had comparable safety, Immunogenicity and efficacy profiles like in HIC. Overall, the LMIC of Africa where immune compromising/modulating situations are prevalent, there is need for long term immunogenicity as well as surveillance studies for long term clinical effectiveness after two and three dose regimens.