Explore the vast range of titles available.

In this interim phase 1–2a trial of an adenovirus-based vaccine (Ad26.COV2.S), participants were divided into two age groups and received one or two injections of either a low-dose or high-dose vaccine or placebo. The vaccine elicited a local injection response in most patients and high titers of neutralizing antibodies in all vaccinated groups. In addition, T-cell responses were noted.

Pertussis vaccination in pregnancy has been introduced in an increasing number of countries to better protect infants against the disease in their first weeks of life. The optimal timing of pertussis vaccination in pregnancy is however still under debate. We systematically reviewed published literature on safety, immunogenicity and effectiveness of pertussis vaccination in pregnancy related to timing of vaccination. The search was conducted using PubMed, MEDLINE and Web of Science and yielded 1623 articles, thereof 777 duplicates. Screening resulted in the inclusion of 45 publications reporting on safety (n = 11), immunogenicity (n = 26) and/or effectiveness (n = 9). We also mapped pertussis recommendations in pregnancy by government institutions globally according to the recommended timing of vaccination. Overall, the selected publications did not indicate increased safety concerns associated with timing of pertussis vaccination in pregnancy. Immunogenicity studies often suggested optimal protection at birth after early third trimester vaccination. Few studies investigated qualitative antibody characteristics, and none investigated antibody titers in breastmilk or cellular-mediated immunity related to timing of vaccination. Effectiveness studies showed decreased vaccine effectiveness of late third trimester pertussis vaccination compared to vaccination earlier in pregnancy. Worldwide, a general recommendation for pertussis vaccination in pregnancy was found for 58 countries, with as many as 22 different recommended timings registered. The timing of pertussis vaccination in pregnancy seems to impact immunogenicity and vaccine effectiveness, with optimal immune responses at birth suggested following early third trimester vaccination and reduced vaccine effectiveness of late third trimester pertussis vaccination suggested compared to vaccination earlier in pregnancy. However, inconsistent and lacking data are reflected in the divergent national recommendations for pertussis vaccination in pregnancy worldwide. Pertussis vaccination in pregnancy aims to protect infants in their first weeks of life. Our review suggests that immunogenicity and vaccine effectiveness are impacted by the timing of vaccination in pregnancy. National recommendations for pertussis vaccination in pregnancy vary widely worldwide.

•COVID-19 vaccine willingness in Flanders (Belgium) was high: 84.2%.•Though we observed significant variations over time (July-December 2020).•We found multiple vaccine-hesitant spatial clusters, mostly at the Flemish borders.•Many socio-demographic and behavioural factors associated with vaccine willingness. A year after the start of the COVID-19 outbreak, the global rollout of vaccines gives us hope of ending the pandemic. Lack of vaccine confidence, however, poses a threat to vaccination campaigns. This study aims at identifying individuals’ characteristics that explain vaccine willingness in Flanders (Belgium), while also describing trends over time (July–December 2020). The analysis included data of 10 survey waves of the Great Corona Survey, a large-scale online survey that was open to the general public and had 17,722–32,219 respondents per wave. Uni- and multivariable general additive models were fitted to associate vaccine willingness with socio-demographic and behavioral variables, while correcting for temporal and geographical variability. We found 84.2% of the respondents willing to be vaccinated, i.e., respondents answering that they were definitely (61.2%) or probably (23.0%) willing to get a COVID-19 vaccine, while 9.8% indicated maybe, 3.9% probably not and 2.2% definitely not. In Flanders, vaccine willingness was highest in July 2020 (90.0%), decreased over the summer period to 80.2% and started to increase again from late September, reaching 85.9% at the end of December 2020. Vaccine willingness was significantly associated with respondents’ characteristics: previous survey participation, age, gender, province, educational attainment, household size, financial situation, employment sector, underlying medical conditions, mental well-being, government trust, knowing someone with severe COVID-19 symptoms and compliance with restrictive measures. These variables could explain much, but not all, variation in vaccine willingness. Both the timing and location of data collection influence vaccine willingness results, emphasizing that comparing data from different regions, countries and/or timepoints should be done with caution. To maximize COVID-19 vaccination coverage, vaccination campaigns should focus on (a combination of) subpopulations: aged 31–50, females, low educational attainment, large households, difficult financial situation, low mental well-being and labourers, unemployed and self-employed citizens.

The aim of this study was to explore vaccine confidence, a factor influencing vaccination uptake, in Flanders (Belgium) during November 2023. The study evaluated confidence in vaccines generally and in specific vaccines: MMR, HPV, seasonal influenza, and COVID-19. This cross-sectional study surveyed 1500 individuals: 1000 from the general population (>18 years) and 500 parents with children (≤13 years). Vaccine confidence was measured using the Vaccine Confidence Index™ (VCI). Weighted analysis and multivariable binary logistic regressions were employed to explore the association between sociodemographic and other potential predictors influencing vaccine confidence. The results showed that 77.9 % (CI 75.0–80.8) of the general population and 81.6 % (CI 76.5–86.6) of parents considered vaccines to be generally safe, while >80 % of both groups saw them as effective and important for children. A total of 56.9 % (CI 53.2–60.6) of the general population and 64.5 % (CI 54.5–74.5) of the parents agreed that vaccines are important, safe, effective, and compatible with their beliefs. Lower VCI scores were observed for COVID-19 (52.1 % (CI 48.2–55.9)) and HPV vaccines (56.2 % (CI 52.2–60.2)) in the general population, and for COVID-19 (50.2 % (CI 39.4–61.0)) and influenza vaccines (61.7 % (CI 51.5–72.0)) among parents. Higher VCI scores were observed in older generations (>45 years) and higher-educated individuals. Most participants are confident in vaccines. While quantitative monitoring has been conducted across Europe, including in Belgium, this monitoring study focuses on Flanders, providing a valuable baseline for future reference. Longitudinal research, preferably including also qualitative research, is needed to further understand trends and how to build and sustain confidence in Flanders.

Our study aims to investigate the dynamics of conventional memory T cells (Tconv) and regulatory memory T cells (Treg) following activation, and to explore potential differences between these two cell types. To achieve this, we developed advanced statistical mixed models based on mathematical models of ordinary differential equations (ODE), which allowed us to transform post-vaccination immunological processes into mathematical formulas. These models were applied to in-house data from a de novo Hepatitis B vaccination trial. By accounting for inter- and intra-individual variability, our models provided good fits for both antigen-specific Tconv and Treg cells, overcoming the challenge of studying these complex processes. Our modeling approach provided a deeper understanding of the immunological processes underlying T cell development after vaccination. Specifically, our analysis revealed several important findings regarding the dynamics of Tconv and Treg cells, as well as their relationship to seropositivity for Herpes Simplex Virus Type 1 (HSV-1) and Epstein-Barr Virus (EBV), and the dynamics of antibody response to vaccination. Firstly, our modeling indicated that Tconv dynamics suggest the existence of two T cell types, in contrast to Treg dynamics where only one T cell type is predicted. Secondly, we found that individuals who converted to a positive antibody response to the vaccine earlier had lower decay rates for both Tregs and Tconv cells, which may have important implications for the development of more effective vaccination strategies. Additionally, our modeling showed that HSV-1 seropositivity negatively influenced Tconv cell expansion after the second vaccination, while EBV seropositivity was associated with higher Treg expansion rates after vaccination. Overall, this study provides a critical foundation for understanding the dynamic processes underlying T cell development after vaccination.

•The combined NTHi-Mcat vaccine had an acceptable safety and reactogenicity profile.•Most reactions were mild/moderate and resolved within a few days after vaccination.•Reactogenicity was highest in the adjuvanted NTHi-Mcat vaccine groups.•The protein vaccine had good immunogenicity in older adults with a smoking history. Non-typeable Haemophilus influenzae (NTHi) and Moraxella catarrhalis (Mcat) are frequent pathogens in acute exacerbations of COPD. We assessed the safety, reactogenicity and immunogenicity of different investigational vaccine formulations containing surface proteins of NTHi (PD and PE-PilA) and Mcat (UspA2) in adults with smoking history ≥10 pack-years, to immunologically represent the COPD population. Participants received two doses 60 days apart in a randomised, observer-blind, placebo-controlled study (NCT02547974). In step 1, 30 healthy adults aged 18–40 years were randomised (1:1) to receive a non-adjuvanted formulation (10-10-PLAIN) or placebo. In step 2, 90 smokers/ex-smokers aged 50–70 years randomly (1:1:1) received an AS01-adjuvanted formulation containing either 10 µg of each antigen (10-10-AS01) or 10 µg of each NTHi antigen and 3.3 µg of Mcat antigen (10-3-AS01), or placebo. Incidences of solicited local adverse events (AEs) tended to be highest in the AS01-adjuvanted vaccine groups. Most solicited AEs had mild/moderate intensity. No vaccine-related serious AEs were reported. The 10-3-AS01 formulation induced the best humoral immune response against the NTHi antigens. Responses against the Mcat antigen were similar across groups, with waning immunogenicity after 30 days post-dose 2. The investigational NTHi-Mcat vaccine had an acceptable safety and reactogenicity profile and good immunogenicity in older adults with a smoking history.

Healthcare providers (HCP) are seen by the public as the most trustworthy source of information about vaccination. While HCPs could be a valuable partner to increase vaccine confidence in general, it is not clear whether they feel confident themselves to address questions concerning vaccination. In the context of the EU Joint Action on Vaccination (EU-JAV), the Vaccine Training Barometer, an online survey tool, was developed to assess how frequently HCPs receive questions about vaccination, how confident they feel to answer these questions, and to what extent they are willing to follow extra training. After a pilot test in Flanders, Belgium, the Barometer was launched and completed by 833 HCPs in Flanders and 291 HCPs in the Spanish regions of Catalonia, Navarre and Valencian Community from November 2020 until January 2021, during the COVID-19 pandemic, just before and during the start of the first COVID-19 vaccination campaigns. In both countries, HCPs frequently received questions about vaccination (mostly on a daily or weekly basis), and about two thirds of them indicated that the frequency of questions had increased during the three months prior to completing the survey. Most questions were about the side effects and safety of vaccines. In both countries, a considerable proportion of HCPs did not feel confident to answer vaccine-related questions (31.5% felt confident in Flanders, 21.6% in Spain). A large proportion of HCPs received questions in the last three months before the survey that they could not answer (52.4% of respondents in Flemish sample, 41.5% in Spanish sample). Only 11.4% (Flanders) and 11.3% (Spain) of the respondents felt they gained sufficient knowledge through their standard education to be able to answer questions about vaccination. Almost all respondents were willing to follow extra training on vaccination (Flanders: 95.4%, Spain: 96.6%). The Vaccine Training Barometer is thus a useful tool to monitor HCPs’ confidence to answer questions about vaccination and to capture their training needs.

[Display omitted] •Systematic review of the impact of two- and one-dose non-live hepatitis A virus vaccination programs in children.•two- and one-dose programs induced rapid declines in incidence of hepatitis A in all age groups.•two-dose programs induced declines in incidence of hepatitis A for ≥14 years.•Effects of one-dose programs on incidence of hepatitis A are unknown beyond 6 years.•Antibody persistence was followed-up and documented for ≥15 and ≥10 years after 2 and one vaccine doses. Hepatitis A virus (HAV) is a global health concern as outbreaks continue to occur. Since 1999, several countries have introduced universal vaccination (UV) of children against HAV according to approved two-dose schedules. Other countries have implemented one-dose UV programs since 2005; the long-term impact of this schedule is not yet known. We conducted a systematic literature search in four electronic databases for data published between January 2000 and July 2019 to assess evidence for one-dose and two-dose UV of children with non-live HAV vaccines and describe their global impact on incidence, mortality, and severity of hepatitis A, vaccine effectiveness, vaccine efficacy, and antibody persistence. Of 3739 records screened, 33 peer-reviewed articles and one conference abstract were included. Rapid declines in incidence of hepatitis A and related outcomes were observed in all age groups post-introduction of UV programs, which persisted for at least 14 years for two-dose and six years for one-dose programs according to respective study durations. Vaccine effectiveness was ≥95% over 3–5 years for two-dose programs. Vaccine efficacy was >98% over 0.1–7.5 years for one-dose vaccination. Antibody persistence in vaccinated individuals was documented for up to 15 years (≥90%) and ten years (≥74%) for two-dose and one-dose schedules, respectively. Experience with two-dose UV of children against HAV is extensive, demonstrating an impact on the incidence of hepatitis A and antibody persistence for at least 15 years in many countries globally. Because evidence is more limited for one-dose UV, we were unable to draw conclusions on immune response persistence beyond ten years or the need for booster doses later in life. Ongoing epidemiological monitoring is essential in countries implementing one-dose UV against HAV. Based on current evidence, two doses of non-live HAV vaccines are needed to ensure long-term protection.

Vaccine confidence remains a global public health challenge, especially highlighted during the COVID-19 pandemic. Public trust in vaccines is crucial, with healthcare providers (HCPs) playing a pivotal role in navigating this sensitive topic. This requires an understanding of HCPs' perceptions of vaccines. Most European studies focus solely on the 27 EU countries, with sparse evidence available among other European countries. This study aims to expand the scope of HCPs' vaccine confidence oversight into European regions where limited research has been conducted thus far. The study employed a mixed-methods approach to examine vaccine confidence among HCPs (general practitioners and nurses) in six European countries outside of the EU: North Macedonia, Bosnia & Herzegovina (Balkans), Belarus (Eastern Europe), Armenia, Georgia (Caucasus), and Kazakhstan (Central Asia). Quantitative surveys (N = 600) assessed vaccine confidence levels and recommendation practices, which were analyzed using SPSS. Qualitative interviews (N = 30) provided deeper insights into HCPs' perceptions of vaccination, role, and training needs, and were processed using NVivo. Findings revealed varying levels of vaccine confidence among HCPs across the six countries. The quantitative survey indicated disparities in confidence levels, with Belarus and Kazakhstan exhibiting notably lower confidence in vaccines. North Macedonia stands out as the country where HCPs are most confident about their role in encouraging vaccination, while the remaining five countries share similar lower levels. Qualitative interviews provided deeper insights into HCP perspectives, highlighting the complexities of tailoring recommendations and the collaborative decision-making process. HCPs expressed a clear need for training on vaccination, particularly in understanding effective doctor-patient communication. These findings underscore the value of implementing targeted interventions to support HCPs, for example by providing training in vaccination knowledge and communication to improve their confidence in addressing patient concerns about vaccination. Ultimately, responding to skills and knowledge needs, this can contribute to improved vaccine acceptance. •HCPs from Belarus and Kazakhstan exhibit the lowest vaccine confidence levels.•Flu and COVID-19 vaccine recommendations drop for pregnant women•HCP vaccine hesitancy impacts their vaccine recommendations.•Training on vaccine communication can boost HCPs' confidence in patient consultations.

We investigated and compared current national vaccination policies for health-care personnel (HCP) in Europe with results from our previous survey. Data from 36 European countries were collected using the same methodology as in 2011. National policies for HCP immunization were in place in all countries. There were significant differences in terms of number of vaccinations, target HCP and healthcare settings, and implementation regulations (recommended or mandatory vaccinations). Vaccination policies against hepatitis B and seasonal influenza were present in 35 countries each. Policies for vaccination of HCP against measles, mumps, rubella and varicella existed in 28, 24, 25 and 19 countries, respectively; and against tetanus, diphtheria, pertussis and poliomyelitis in 21, 20, 19, and 18 countries, respectively. Recommendations for hepatitis A immunization existed in 17 countries, and against meningococcus B, meningococcus C, meningococcus A, C, W, Y, and tuberculosis in 10, 8, 17, and 7 countries, respectively. Mandatory vaccination policies were found in 13 countries and were a pre-requisite for employment in ten. Comparing the vaccination programs of the 30 European countries that participated in the 2011 survey, we found that more countries had national vaccination policies against measles, mumps, rubella, hepatitis A, diphtheria, tetanus, poliomyelitis, pertussis, meningococcus C and/or meningococcus A, C, W, Y; and more of these implemented mandatory vaccination policies for HCP. In conclusion, European countries now have more comprehensive national vaccination programs for HCP, however there are still gaps. Given the recent large outbreaks of vaccine-preventable diseases in Europe and the occupational risk for HCP, vaccination policies need to be expanded and strengthened in several European countries. Overall, vaccination policies for HCP in Europe should be periodically re-evaluated in order to provide optimal protection against vaccine-preventable diseases and infection control within healthcare facilities for HCP and patients.