Antibody persistence after a single dose of quadrivalent HPV vaccine and the effect of a dose of nonavalent vaccine given 3-8 years later – an exploratory study

Abstract

The objective of this study was to assess the persistence of antibodies after a single dose of quadrivalent HPV vaccine (4vHPV) and the effect of a dose of nonavalent HPV vaccine (9vHPV) given 3-8 years later. Such data might be of interest in the decision-making process regarding the 2-dose course completion in non-compliant vaccinees in jurisdictions which switched from 4vHPV to 9vHPV. Girls who previously received a single dose of 4vHPV were eligible to participate. Blood specimens were collected just before and one month post-9vHPV administration. The specimens were tested by ELISA for the presence of antibodies to 9 HPV types included in the 9vHPV. Thirty-one girls aged 13-18 years (mean 15.5 years) participated in the study. Pre-9vHPV administration, all participants were seropositive to 4 HPV types included in 4vHPV and 58%-87% were seropositive to the five other HPV types included in the 9vHPV. GMTs were 6.1 AU/ml, 7.7 AU/ml, 20.1 IU/ml and 6.3 IU/ml to HPV6, HPV11, HPV16 and HPV18, respectively. The GMTs for the other five HPV types varied from 1.0 to 2.9 AU/ml. One month post-9vHPV administration all 31 participants were seropositive to all 9 HPV types with a 36.1 to 89.1-fold increase of GMTs. High seropositivity rates observed several years after a single dose of 4vHPV and 100% seropositivity after a dose of 9vHPV suggest that this schedule might be used in non-compliant vaccinees or when switching immunization programs from 4vHPV to 9vHPV. ARTICLE HISTORY

Immunogenicity of Alternative Dosing Schedules for HPV Vaccines among Adolescent Girls and Young Women: A Systematic Review and Meta-Analysis

“…Ages were aggregated in the following ranges to match current HPV vaccine policy and in response to differential immunogenicity by age group: 9-14 and 15-26. Studies with reported data aggregated across our age groups (e.g., ages 10-18) were excluded, with one exception: Gilca 2019 [20], a key source of single and extended dose data, which reported aggregated results for ages [13][14][15][16][17][18]. As prior research shows that younger groups tend to have higher immunogenicity [21], these data were coded as 9-14 for a more conservative estimate of immune response in alternative schedules.…”

Virus-like Particle-Based L2 Vaccines against HPVs: Where Are We Today?

“…VLP-based HPV vaccines have recently been shown to prevent cases of cervical intraepithelial neoplasias, with protection levels lasting for at least 10 years [19,20]. Moreover, recent studies show that a single dose of the HPV VLP-based vaccine can lead to long-lasting protection from HPV infection [21]. These vaccines are based on VLPs derived from over-expression of the capsid proteins in yeast (Gardasil vaccines) or in insect cells (Cervarix vaccine).…”

“…Although aforementioned preclinical protective studies look promising, there are still some questions that remain to be answered with both candidate vaccines. For example, we still do not know if immune responses elicited by HPV16 L1-16L2 (aa 17-31) VLPs or mixed MS2-L2 VLPs will last 3-8 years, as has been shown with a single dose of Gardasil-4 [21]. Recent preclinical studies with four doses (25-50 µg/dose) of HPV16 L1-16L2 (aa 17-31) VLPs show that the antibodies are protective 1 year after immunization [69].…”

Long intervals between two doses of HPV vaccines and magnitude of the immune response: a post hoc analysis of two clinical trials

“…26 The relative titers across types are the same for the 9-10 year old pre-adolescents not yet sexually active and 13-18-years-old adolescents, an age group in which we cannot rule out sexual activity. 27,28 This observation suggests that adolescents vaccinated with one dose of vaccine are not getting significant boosting from viruses shed by their sex partners. A study conducted in the same province five years post vaccination program implementation showed a 1% combined prevalence of HPV6/11/16/18 DNA in 17-19 year-old sexually active girls.…”

“…6,29 Methods Data were obtained from two previously reported clinical trials conducted by our team, in Quebec City, Quebec, Canada. 27,28 The serological assays for both studies were performed using a 9-plex VLP IgG ELISA (M9ELISA) at the Centers for Disease Control and Prevention (CDC, Atlanta, USA). 30 Antibody titers were measured in International Units (IU/ml) for HPV16 and 18.…”