Are two doses of human papillomavirus vaccine sufficient for girls aged 15-18 years? Results from a cohort study in India

Impact of age at vaccination and cervical HPV infection status on binding and neutralizing antibody titers at 10 years after receiving single or higher doses of quadrivalent HPV vaccine

Long-term follow-up of a cohort of unmarried girls who received one, two, or three doses of quadrivalent HPV vaccine, between 10 and 18 years of age, in an Indian multi-centric study allowed us to compare antibody responses between the younger and older age cohorts at 10-years post-vaccination, and study the impact of initiation of sexual activity and cervical HPV infections on antibody levels. Among the younger (10-14 years) recipients of a single dose, 97.7% and 98.2% had detectable binding antibody titers against HPV 16 and HPV 18 respectively at ten years post-vaccination. The proportions among those receiving a single dose at age 15-18 years were 92.3% and 94.2% against HPV 16 and HPV 18 respectively. Mean HPV 16 binding antibody titers were 2.1 folds (95%CI 1.4 to 3.3) higher in those vaccinated at ages 10-14 years, and 1.9 folds (95%CI 1.2 to 3.0) higher in those vaccinated at 15-18 years compared to mean titers seen in the unvaccinated women. Compared to previous timepoints of 36 or 48 months, binding antibodies against HPV 16 and neutralizing antibodies against both HPV 16 and HPV 18 were significantly higher at 10 years. This rise was more pronounced in participants vaccinated at 15-18 years. No association of marital status or cervical HPV infections was observed with the rise in titer. Durability of antibody response in single dose recipients correlated well with the high efficacy of a single dose against persistent HPV 16/18 infections irrespective of age at vaccination, as we reported earlier.

Immunogenicity and safety of a new quadrivalent HPV vaccine in girls and boys aged 9-14 years versus an established quadrivalent HPV vaccine in women aged 15-26 years in India: a randomised, active-controlled, multicentre, phase 2/3 trial

BACKGROUND

To meet global cervical cancer elimination efforts, a wider range of affordable and accessible vaccines against human papillomavirus (HPV) are needed. We aimed to evaluate the immunogenicity and safety of a quadrivalent HPV vaccine (targeting HPV types 6, 11, 16, and 18), developed and manufactured by the Serum Institute of India (SIIPL). Here we report outcomes in the 9-14 years cohort.

METHODS

This randomised, active-controlled, phase 2/3 trial was conducted at 12 tertiary care hospitals across India. Healthy participants aged 9-14 years or 15-26 years with no history of HPV vaccination were eligible for enrolment. Female participants were randomly assigned (1:1) with an interactive web response system, by use of a central computer-generated schedule and block randomisation (block sizes of 2, 4, 6, and 8), to receive the SIIPL quadrivalent HPV vaccine (Cervavac; SIIPL, Pune, India) or the comparator quadrivalent HPV vaccine (Gardasil; Merck Sharp & Dohme, Harleem, the Netherlands). Participants, investigators, laboratory technicians, and sponsors were masked to treatment allocation of female participants. Male participants were given the SIIPL quadrivalent HPV vaccine in an open-label manner. Study vaccines were administered intramuscularly with a two-dose schedule (at day 0 and 6 months) in the cohort aged 9-14 years, and with a three-dose schedule (at day 0, month 2, and month 6) in the cohort aged 15-26-years. Immunogenicity was assessed 30 days after the last dose by use of multiplexed ELISA. The primary outcome was the non-inferiority of immune response in terms of the geometric mean titre (GMT) of antibodies against HPV types 6, 11, 16, and 18 generated by the SIIPL quadrivalent HPV vaccine in girls and boys (aged 9-14 years) compared with the GMT generated by the comparator quadrivalent HPV vaccine in women aged 15-26 years at month 7 in the modified per-protocol population (ie, all participants who received all doses of study vaccines per assigned treatment group and had both day 0 and 1-month immunogenicity measurements after the last dose following protocol-defined window periods with no major protocol deviations). Non-inferiority was established if the lower bound of the 98·75% CI of the GMT ratio was 0·67 or higher. The co-primary outcome of occurrence of solicited adverse events (within 7 days of each dose) and unsolicited adverse events (up to 30 days after the last dose) was assessed in all participants who were enrolled and received at least one dose of study vaccine. The trial is registered with the Clinical Trials Registry - India (CTRI/2018/06/014601), and long-term follow-up is ongoing.

FINDINGS

Between Sept 20, 2018, and Feb 9, 2021, 2341 individuals were screened, of whom 2307 eligible individuals were enrolled and vaccinated: 1107 (738 girls and 369 boys) in the cohort aged 9-14 years and 1200 (819 women and 381 men) in the cohort aged 15-26 years. No race or ethnicity data were collected. 350 girls and 349 boys in the SIIPL quadrivalent HPV vaccine group and 338 women in the comparator vaccine group were included in the modified per-protocol population for the primary endpoint analysis. The median follow-up for the analyses was 221 days (IQR 215-231) for girls and 222 days (217-230) for boys in the SIIPL quadrivalent HPV vaccine group, 223 days (216-232) for girls in the comparator vaccine group, and 222 days (216-230) for women in the comparator vaccine group. GMT ratios were non-inferior in girls and boys receiving the SIIPL quadrivalent HPV vaccine compared with women receiving the comparator vaccine: GMT ratios for girls were 1·97 (98·75% CI 1·67-2·32) for HPV type 6, 1·63 (1·38-1·91) for HPV type 11, 1·90 (1·60-2·25) for HPV type 16, and 2·16 (1·79-2·61) for HPV type 18. For boys the GMT ratios were 1·86 (1·57-2·21) for HPV type 6, 1·46 (1·23-1·73) for HPV type 11, 1·62 (1·36-1·94) for HPV type 16, and 1·80 (1·48-2·18) for HPV type 18. The safety population comprised all 1107 participants (369 girls and 369 boys in the SIIPL quadrivalent HPV vaccine group, and 369 girls in the comparator group). Solicited adverse events occurred in 176 (48%) of 369 girls and 124 (34%) of 369 boys in the SIIPL vaccine group and 179 (49%) of 369 girls in the comparator vaccine group. No grade 3-4 solicited adverse events occurred within 7 days of each dose. Unsolicited adverse events occurred in 143 (39%) girls and 147 (40%) boys in the SIIPL vaccine group, and 143 (39%) girls in the comparator vaccine group. The most common grade 3 unsolicited adverse event was dengue fever, in one (<1%) girl in the SIIPL vaccine group and three (1%) girls in the comparator group. There were no grade 4 or 5 adverse events. Serious adverse events occurred in three (1%) girls and three (1%) boys in the SIIPL vaccine group, and five (1%) girls in the comparator vaccine group. No vaccine-related serious adverse events were reported. There were no treatment-related deaths.

INTERPRETATION

We observed a non-inferior immune response with the SIIPL quadrivalent HPV vaccine in girls and boys aged 9-14 years and an acceptable safety profile compared with the comparator vaccine. These findings support extrapolation of efficacy from the comparator vaccine to the SIIPL quadrivalent HPV vaccine in the younger population. The availability of the SIIPL quadrivalent HPV vaccine could help meet the global demand for HPV vaccines, and boost coverage for both girls and boys globally.

FUNDING

Biotechnology Industry Research Assistance Council, Department of Biotechnology (DBT), Government of India, and Serum Institute of India.

Human papilloma virus vaccines: A comprehensive narrative review

Cervical cancer is one of the most common cancers in women aged 15-44 years in the world, with more than three-quarters of cases diagnosed at a locally advanced clinical stage with minor prospects of survival. Although only a small percentage of women with Human Papilloma Virus (HPV) develop cervical cancer and most of the HPV infections are cleared subsequently at primary stage itself, but seroconversion not always guarantees that the individual is immune to HPV. The advent of the cervical carcinoma vaccine has raised the expectations that eradication of cervical carcinoma might be possible in the near future as it exhibited remarkably high efficacy against the vaccine-specific types in naive women with no serious vaccine-related adverse events. Few prophylactic HPV vaccines are currently licensed in over 100 countries. It has also been suggested that vaccinating both men and women is more beneficial than vaccinating only females. Vaccination is a cost-effective strategy to reduce the incidence of cervical cancer and mortality compared to no vaccination based on the cost of cancer treatment. Well-coordinated vaccination strategy with focus on adolescent girls and if possible, boys can lead to dramatic impact on disease reduction around the world.

Different dose series of human papillomavirus vaccine in young females: a pair-wise meta-analysis and network meta-analysis from randomized controlled trials

Objective

To investigate the application value of different dose of HPV vaccine in young females.

Data sources

The following databases were searched: Cochrane Library, PubMed, Embase, Web of Science, SINOMED, and Wanfang Data, from the establishment of the database to August 1st, 2022.

Study eligibility criteria

The inclusion criterias were: healthy young women younger than 25 years old as the research object, randomized controlled study as the research type, and the efficacy and safety of single-dose, two-dose or three-dose HPV vaccines as the intervention measures and research endpoints.

Study appraisal and synthesis methods

Meta-analysis was performed to analyze the protective effects of single-dose, 2-dose and 3-dose HPV vaccine series on young females.

Results

A total of eight eligible studies involving 16 publications were included. There is no difference in the immunogenicity between the 2-dose and 3-dose series within 12 months after the last dose of HPV vaccine. However, 3-dose series was better than the 2-dose series, which performed better than the single-dose vaccine, after 12 months. With respect to the prevention of HPV16/18 infection or HPV31/33/45 infection, the single-dose vaccine worked better than 2-dose or 3-dose series.

Conclusions

The present study showed that the immunogenicity of low-dose HPV vaccine was significantly less, but it reduced the risk of high-risk HPV infection. The low-dose HPV vaccine series may not offer a preventive effect on cervical lesions, though it needs to be further confirmed by additional studies.

Stated preferences for human papillomavirus vaccination for adolescents in selected communities in Ibadan, Southwest Nigeria: A discrete choice experiment

Administration of the human papillomavirus (HPV) vaccine in early adolescence is effective in preventing cervical cancer, a common cancer in sub-Saharan Africa. Nigeria is in the pre-introduction era of the HPV vaccine. Understanding the preferences of the population for the vaccine can help design the HPV immunization program to ensure high uptake of the vaccine. This study explored the preferences for the HPV vaccine among stakeholders in selected communities in Ibadan, Nigeria. A discrete choice experiment survey based on six attributes of the HPV vaccine (which were the number of doses, the efficacy of the vaccine, cost of the vaccine, location of the service point, other benefits of the vaccine apart from prevention of cervical cancer and the odds of a side effect from the vaccine) was carried out in five communities. Data were analyzed using conditional and mixed logit models. Seven hundred community members were recruited, 144 (20.7%) were adolescents and 248 (35.4%) were males. In line with expectations, respondents preferred vaccines with higher efficacy, less severe side effects and lower costs. Preference heterogeneity was identified for adolescents that were less price-sensitive and other community members who were less likely to prefer using schools as the service point. The high socioeconomic class preferred a vaccine that also prevents genital warts. There were variabilities in the preferences for the attributes of the HPV vaccine in the study communities. These variabilities need to be considered in the introduction of the HPV vaccine to ensure high uptake of the vaccine.

Humans with inherited T cell CD28 deficiency are susceptible to skin papillomaviruses but are otherwise healthy

We study a patient with the human papilloma virus (HPV)-2-driven "tree-man" phenotype and two relatives with unusually severe HPV4-driven warts. The giant horns form an HPV-2-driven multifocal benign epithelial tumor overexpressing viral oncogenes in the epidermis basal layer. The patients are unexpectedly homozygous for a private CD28 variant. They have no detectable CD28 on their T cells, with the exception of a small contingent of revertant memory CD4+ T cells. T cell development is barely affected, and T cells respond to CD3 and CD2, but not CD28, costimulation. Although the patients do not display HPV-2- and HPV-4-reactive CD4+ T cells in vitro, they make antibodies specific for both viruses in vivo. CD28-deficient mice are susceptible to cutaneous infections with the mouse papillomavirus MmuPV1. The control of HPV-2 and HPV-4 in keratinocytes is dependent on the T cell CD28 co-activation pathway. Surprisingly, human CD28-dependent T cell responses are largely redundant for protective immunity.

Immunogenicity of 2 and 3 Doses of the Quadrivalent Human Papillomavirus Vaccine up to 120 Months Postvaccination: Follow-up of a Randomized Clinical Trial

Background

Several countries have implemented a 2-dose (2D) human papillomavirus (HPV) vaccination schedule for adolescents based on immunobridging studies. We compared immunogenicity of 2D vs 3-dose (3D) schedules of the quadrivalent vaccine (4vHPV) up to 10 years after the first dose.

Methods

Girls aged 9–13 years were randomized to receive 2D or 3D and were compared with women aged 16–26 receiving 3D at day 1 and months 7, 24, and 120 after the first dose. Antibody levels for HPV6/11/16/18 were evaluated using the competitive Luminex immunoassay (cLIA) and total immunoglobulin G assay. Geometric mean titers (GMTs) and seropositivity rates were compared between the different groups at different time points. Noninferiority of GMT ratios was defined as the lower bound of the 2-sided 95% confidence interval (CI) being greater than 0.5. Kinetics of antibody titers over time among study groups were examined.

Results

At 120 months, data from 35 2D girls, 38 3D girls, and 30 3D women were used for analyses. cLIA seropositivity rates were above 95% for all HPV vaccine types and all schedules, except HPV18, with the lowest seropositivity observed among 3D women (60.0%; 95% CI, 40.6%–77.3%). GMT ratios (cLIA) for both 2D and 3D girls were noninferior to 3 doses in women for HPV6/11/16/18. Trends were comparable between assays.

Conclusions

GMTs for HPV6/11/16/18 after 2D or 3D of 4vHPV in girls were noninferior to 3D in adult women up to 120 months postvaccination. This study demonstrates long-term immunogenicity of the 2D HPV vaccine schedule.

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

BACKGROUND

The 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.

METHODS

PubMed 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.

RESULTS

Data 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.

CONCLUSIONS

RCTs 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.

Experience of Human Papillomavirus Vaccination Project in a Community Set Up-An Indian Study

Background:

Initial introduction of HPV vaccination from 2006 to 2008 was largely confined to high-income countries (HIC), such as Australia, the United States, and Europe, where cervical cancer incidence is lowest. Much of the post-introduction literature has come from HICs, with a focus on coverage levels achieved, provider acceptability and early impact of vaccination on disease endpoints. However, there are a few literature evaluating the mechanics of delivery, feasibility of the health system and acceptability from low and middle income countries (LMICs). The primary objective was to evaluate the feasibility, acceptability and safety of two dose HPV vaccination in adolescent girls between 9-14 years.

Methods:

After an orientation camp followed by filling up of prevaccine questionnaires by parents on HPV related diseases and its vaccines and informed consent, girls between9-14years were vaccinated. They were asked to report any side effects in the next 24 hours after each dose. Parents were contacted on Day 7 and Day 30 to enquire about any side effects . Total 3 visits were required i.e two for the vaccination and one visit at 7th month post completion of second dose. To estimate the acceptability, successful completion of two doses by at least 80% of the girls were measured. For measurement of acceptability, either of the parents were recalled along with their daughter at 7th month and were asked to fill up a pre-set questionnaire.

Results:

After institutional ethical clearance, 555 girls were recruited in the study from rural parts of West Bengal, India between July, 2017 to November, 2017. Out of which, 544 girls (98%) received their 2^nd dose between January, 2018 and May, 2018 without any serious adverse effects. No serious adverse effect was reported on follow up till December, 2019.

Conclusion:

The introduction of HPV vaccination is feasible in large scale and the vaccine is well accepted and safe.

Current and future vaccine clinical research with the licensed 2-, 4-, and 9-valent VLP HPV vaccines: What's ongoing, what's needed?

Prophylactic HPV vaccination has been a great public health success. For >20 years, clinical trials were conducted with the 2-, 4-, and/or 9-valent vaccines in young-adult females, mid-adult women, males, and adolescents. In all studies, the vaccines were highly efficacious, immunogenic, and well tolerated. Following vaccine licensure and utilization in national vaccine programs globally (real-world settings primarily in high income countries), numerous studies demonstrated that the vaccines continue to have an excellent safety profile and have dramatically reduced the incidence of genital warts, HPV vaccine-type prevalence, and precancerous lesions. Thirty-eight clinical trials with the currently licensed HPV vaccines are ongoing. Key questions being addressed in new trials include: efficacy against persistent infection and immunogenicity of a 1-dose regimen; efficacy of 3 doses in 20-45-year-old females; use in postpartum women and immunocompromised individuals (HIV, liver and kidney transplants); dose sparing via intradermal administration; use in combination with a PD1 monoclonal antibody in patients with cervical cancer; impact on recurrent disease in women undergoing cervical conization; persistence of protection; and use to prevent oropharyngeal cancer. Additional clinical research that should be conducted includes: long-term follow-up, particularly of 1- and 2-dose regimens; further evaluation of flexible 2-dose regimens; immunogenicity of 1- or 2-dose regimens in persons ≥15 years old and immunocompromised populations; safety and immunogenicity of 1 or 2 doses in children <9 years old; assessment of the vaccine in the prevention of transmission; interchangeability with newer HPV vaccines; additional concomitant use studies; and prevention of penile cancer and recurrent respiratory papillomatosis.

Human papillomavirus vaccination: Good clinical practice recommendations from the Federation of Obstetric and Gynecological Societies of India

Human papillomavirus (HPV) vaccination offers an excellent prospect for the primary prevention of cervical cancer. The bivalent and quadrivalent vaccines are both available in India. The nonavalent vaccine is licensed but not yet available. However, there still remain controversies regarding the vaccination of older women, immunocompromised females and other special groups. To provide recommendations for HPV vaccination in India. The Federation of Obstetric and Gynecological Societies of India (FOGSI) convened an expert group on cervical cancer prevention to formulate good clinical practice recommendations (GCPR) with respect to vaccine efficacy and safety, target groups, optimal timing and dosing schedules. HPV vaccines are licensed for females aged 9-45 years in India and have been seen to be safe and effective. FOGSI recommends HPV vaccination of all girls <15 years of age as the best target group, in whom two-doses at an interval of 6 months, extendable to 18 months, are recommended. Three-doses are recommended in girls >15 years of age, immunocompromised persons and sexual assault survivors. Older women and women with abnormal screening results may be vaccinated with an understanding that vaccination does not protect against already acquired infections and screening has to continue. Single-dose vaccination results are promising. Increased awareness is required to reduce vaccine hesitancy. HPV vaccination should be the priority to achieve the elimination of cervical cancer. The introduction of affordable HPV vaccines and reduced dose schedules will improve coverage.

Chinese mothers' intention to vaccinate daughters against human papillomavirus (HPV), and their vaccine preferences: a study in Fujian Province

Little is known regarding Chinese mothers' intention to vaccinate their daughters against human papillomavirus (HPV) since the HPV vaccine was approved for use in China in 2016. The aim was to explore maternal HPV vaccination acceptance, preference for 2-, 4- or 9-valent HPV vaccine and acceptance of domestically manufactured HPV vaccines. Study participants were mothers of primary school children in Southeastern region of Fujian. An online cross-sectional survey was undertaken between June and August 2019. Among the total of 3,586 completed responses (response rate 28.5%), the intention to vaccinate daughter against HPV was high (83.3%). Higher maternal education and perceived benefit and barriers were associated with greater intention to vaccinate. Among mothers who did not intend to vaccinate their daughters, the three most common reasons were daughter being too young to receive HPV vaccination (40.6%), fear of side effects (31.9%) and vaccine price is too high (16.0%). The largest proportion (41.4%) preferred their daughter to be vaccinated with the 9-valent HPV vaccine (9vHPV). Greater preference for 9vHPVwas strongly associated with higher maternal education level and annual household income. The majority of mothers expressed a preference for imported HPV vaccine (56.3%). Our result indicates that lower intentions to vaccinate daughters against HPV among less educated and lower-income mothers may lead to significant social inequalities in HPV vaccine uptake in the country.

Eliminating Cervical Cancer in Mali and Senegal, Two Sub-Saharan Countries: Insights and Optimizing Solutions

BACKGROUND

The number of cases with cervical cancer is rapidly increasing in Sub-Saharan Africa driven by inadequate rates of human papilloma virus (HPV) vaccination and screening programs and accompanied by poor health delivery systems. There are other factors to contend with such as lack of awareness, social myths, reluctance to vaccine acceptance and stigma with sexually transmitted diseases. Here, we formulate strategies to implement intervention programs against HPV infections and other risk factors for cervical cancer in these countries.

METHODS

We searched PubMed, Web of Science, and African Journals Online for this review. The current status of anti-HPV vaccination and precancerous screening programs in Mali and Senegal has been assessed by onsite visits. Collaborators from Mali and Senegal collected data and information concerning HPV vaccination and screening programs in these countries.

FINDINGS

We found that anti-HPV vaccination and cervical cancer screening have been conducted sporadically mainly in urban areas of Mali and Senegal. No known population-based programs are in progress in either of the two countries. We highlighted the advantages and drawbacks of currently available screening tests and proposed that screening by visual inspection with acetic acid (VIA) accompanied by self-sampling is the most cost-effective, culturally acceptable and most feasible strategy to implement in primary care settings. In addition, HPV DNA testing would be affordable, if local laboratory facilities could be established. We found that many of the factors that increase HPV acquisition and promote the oncogenic effect of the virus are largely widespread in both Senegal and Mali. These include infections with HIV and other sexually transmitted infections (STIs), immunosuppression, polygamous marriages, high parity, early sexual activities, early pregnancies, and multiple sexual partners.

INTERPRETATION

Neither vaccines nor screening tests are within the reach of the population in Mali and Senegal because of the high cost. The effective intervention measure would be to integrate anti-HPV vaccines into the Extended Program for Immunization (EPI), which has saved 3 million young lives per year in Africa with the support of GAVI, to implement cost control mechanisms for HPV vaccinations via price negotiations with manufacturing companies, as has recently been done by Rwanda. The collective efforts by local governments, researchers, private sector, and donors may lead to the introduction of affordable screening tests. A robust awareness campaign coupled with sustained and regular engagement of local communities about the prevention and risk factors is extremely important. The projected solutions may be well applicable to other Sub-Saharan countries that face similar challenges containing cervical cancer.

Current status of human papillomavirus vaccination in India's cervical cancer prevention efforts

Efforts are being made to scale up human papillomavirus (HPV) vaccination for adolescent girls in India. Bivalent and quadrivalent HPV vaccines were licensed in the country in 2008, and a nonavalent vaccine was licensed in 2018. Demonstration projects initiated in Andhra Pradesh and Gujarat in 2009 introduced HPV vaccination in public health services in India. Following a few deaths in these projects, although subsequently deemed unrelated to vaccination, HPV vaccination in research projects was suspended. This suspension by default resulted in some participants in a trial evaluating two versus three doses receiving only one dose. Since 2016, the successful introduction of HPV vaccination in immunisation programmes in Punjab and Sikkim (with high coverage and safety), government-sponsored opportunistic vaccination in Delhi, prospects of a single dose providing protection, and future availability of an affordable Indian vaccine shows promise for future widespread implementation and evaluation of HPV vaccination in India.

Current issues facing the introduction of human papillomavirus vaccine in China and future prospects

The introduction of human papillomavirus (HPV) vaccination in China aims to prevent HPV infection in all women. The issues that China might face include high cost of vaccines made in other countries, shortage in HPV vaccine supply, negative events attributed to vaccination (whether justified or not) that jeopardizes the general public's confidence in the HPV vaccine, cultural and literacy barriers, and sensitivity to receiving a vaccine for a sexually transmitted disease. Ensuring the effective delivery of the HPV vaccine in China, a country with vast economic, geographical, and cultural complexities, will require a commitment of significant resources. In light of the high price of imported vaccines, the availability of locally manufactured HPV vaccines would greatly facilitate the national HPV vaccination program. New evidence supporting the efficacy of a two-dose regime in younger adolescents would also be advantageous in terms of affordability and logistical simplicity of vaccine administration. Furthermore, it would potentially enhance the compliance and uptake, especially for hard to reach women in remote regions.

Two-dose recommendation for Human Papillomavirus vaccine can be extended up to 18 years - updated evidence from Indian follow-up cohort study

Earlier publication from the ongoing multi-centric study of the International Agency for Research on Cancer to evaluate less than three doses of the quadrivalent Human Papillomavirus (HPV) vaccine in India amongst unmarried girls demonstrated non-inferior total antibody titres, neutralizing antibody titres and antibody avidity in 2-dose recipients compared to 3-dose recipients at 15-18 years of age (Bhatla et al., 2018) [7]. The number of participants recruited at 15-18 years of age was 1515 and 1795 in the 3-dose and the 2-dose groups respectively. At a median follow-up of 7 years, incident HPV 16/18 infections were detected in 1.6% women receiving two doses and 0.8% women receiving three doses at 15-18 years. Frequency of incident infection was 7.0% in the age- and site-matched unvaccinated women (N = 1484). No persistent infection from HPV 16 was observed in the 2- or 3-dose recipients and one (0.2%) persistent HPV 18 infection was documented, each in the 3-dose and 2-dose cohorts. Among the unvaccinated women, the frequency of HPV 16/18 persistent infection was 1.7%. The protection offered by two doses of quadrivalent HPV vaccine against incident and persistent infections in recipients at 15-18 years is comparable to that seen in 3-dose recipients at 15-18 years.

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.

Immunogenicity and safety of a mixed vaccination schedule with one dose of nonavalent and one dose of bivalent HPV vaccine versus two doses of nonavalent vaccine - A randomized clinical trial

BACKGROUND

Limited data is available on the use of different HPV vaccines in the same subjects. We evaluated the immunogenicity and safety of a mixed vaccination schedule with one dose of nonavalent (9vHPV) and one dose of bivalent vaccine (2vHPV) administered in different order versus two doses of 9vHPV vaccine.

METHODS

371 girls and boys aged 9-10 years were randomized (1:1) to receive (I) two doses of 9vHPV or (II) a mixed schedule of 2vHPV + 9vHPV or 9vHPV + 2vHPV with a 6 month interval. Antibodies to HPV were tested by ELISA in blood samples collected one or six months post-first dose and one month post-second dose.

RESULTS

Post-first dose of 9vHPV 99.4-100% of subjects were seropositive to 9 HPV types included in the vaccine. GMTs varied from 5.0 to 73.6 IU(AU)/ml depending on HPV type. Post-first dose of 2vHPV all subjects were seropositive to HPV16 and 18 (GMTs 16.7 and 11.7 IU/ml, respectively) and 50.0-76.7% were seropositive to 7 types not included in 2vHPV (GMTs varied from 0.3 to 17.5 AU/ml depending on type). Post-second dose all subjects, regardless of the study group, were seropositive to 9 HPV types included in 9vHPV. Anti-HPV16 and 18 GMTs were higher in subjects with the mixed schedule and for the other 7 HPV types higher in subjects who received two doses of 9vHPV vaccine. A higher proportion of subjects who received 2vHPV reported local or systemic adverse events than those who received 9vHPV as the first dose. Post-second dose there were no differences in reported adverse events between the two vaccines.

CONCLUSIONS

The results show the mixed HPV vaccination schedules used in this study are immunogenic and have an acceptable safety profile. Although the seroprotective threshold of antibodies remains unknown the 100% seropositivity to all 9 HPV types included in 9vHPV and the increase of GMTs observed in all study groups post-second dose administration are reassuring and suggest protection might be achieved regardless of the schedule used.

CLINICAL TRIALS REGISTRATION

Clinicaltrials.gov NCT02567955.