Hella Pasmans (Netherlands)
RIVM IIVPresenter of 3 Presentations
CHANGES IN HPV SEROPREVALENCE FROM AN UNVACCINATED TOWARDS A GIRLS-ONLY HPV VACCINATED POPULATION IN THE NETHERLANDS (ID 370)
Abstract
Introduction
In the Netherlands, HPV vaccination was included in the National Immunisation Programme for 12-year old girls in 2010 with the bivalent vaccine. Vaccine uptake initially increased from 56% to 61%, but declined to 45%. To assess its impact on the population level, we examined the changes in HPV seroprevalence in the Dutch population comparing pre-and post-vaccination data.
Methods
Serum samples were used of men and women (0-89 years of age) from two nationwide cross-sectional population based serosurveillance studies performed before (2006-07 survey, n=6384) and after (2016-17 survey, n=6612) implementation of HPV-vaccination in the Netherlands. The last survey included an oversampling of the migrant population. Seven high-risk HPV-specific antibodies; HPV16, 18, 31, 33, 45, 52 and 58, were tested in a VLP-based multiplex-immunoassay. Vaccinated individuals were excluded from seroprevalence and riskfactor analyses.
Results
Preliminary results show us that overall HPV-prevalence is higher in the 2016-17 survey compared to the 2006-07 survey, 25.8% and 23.6%, respectively. Prevalence for HPV16 was highest (13% and 11.4%) and males have a lower seroprevalence than females. The step up in HPV-seroprevalence occurred around 15-19 years of age in both study periods, especially in women. HPV seropositivity for any type was significantly associated with sex, ethnicity, number of sexual partners and history of reported STD. Interestingly, seroprevalence for HPV16 in men was lower in the post-vaccination survey. Although in the male age group 15-39 this effect was not significant(Table 2).
Conclusions
We showed that HPV-seroprevalence has risen in the Netherlands in a decade, especially in women. Interestingly, a decrease in HPV16 seroprevalence among the male population was observed. This effect seems to be unlikely to be attributed to herd immunity from the girls-only HPV-vaccination program since the seroprevalence among men in age 15-39 years, likely to benefit from vaccination effect in women, between the surveys was not statistically significant different.
CHARACTERIZATION OF THE EARLY CELLULAR IMMUNE RESPONSES INDUCED BY HPV VACCINES AND THE RELATION TO LONG-TERM IMMUNITY (ID 261)
Abstract
Introduction
Vaccination triggers a broad array of immune cells. Early reactions, almost immediate after vaccination, include induction of innate cells followed by recruitment and activation of antigen-specific B- and T-cells. Here we analyzed a broad set of cellular immune responses induced by two HPV vaccines to get a better understanding of the early immune responses. Moreover, we aim to correlate these to long-term antibody and cellular responses.
Methods
We studied innate, plasma-cell, antibody, memory B-cell and T-cell responses in 20 healthy HPV-seronegative women following a three-dose schedule with either the bivalent or nonavalent HPV vaccine. Peripheral blood samples were collected at eight predefined time-points after primary vaccination and four time-points post booster. These samples were subjected to in-depth analysis of up to 250 innate and adaptive immune cell subsets by the means of high-throughput flow cytometry (Blanco et al., JACI, 2018), specific antibody levels analyzed by VLP-based MIA and specific memory B and T-cell responses determined by ELISPOT assays.
Results
Preliminary results revealed early expansion of several innate cell subsets already at day 1 after the first vaccination. This expansion was followed by a T-cell response at day 3, showing a difference in Thelper (Th) cell skewing between the two vaccinated groups. All donors showed a clear expansion of plasma cells at day-7 post vaccination, which were mostly of the IgG1 isotype. This study is ongoing and the cellular dynamics of all participants at all time points will be analysed.
Conclusions
For the first time we show an in depth analysis of immune cellular dynamics after HPV vaccinations. Based on the preliminary analysis of the results after the first HPV vaccination we conclude that the kinetics of multiple innate and adaptive immune cell subsets post vaccination are intriguing. All results will be further discussed at the IPVC.