Prospective incidence epidemiology study protocol: conducting active surveillance to assess the burden of Lyme disease (BOLD) in primary care practices in endemic areas of six European countries.

INTRODUCTION: Lyme disease (LD) is the most frequent tick-borne disease in the moderate climates of Europe. This study will inform the phase III efficacy study for Pfizer and Valneva's investigational Lyme disease vaccine, VLA15. VLA15 phase III will be conducted in the USA and Europe due to the vaccine's serotype coverage and public health burden of LD. In Europe, the existence and location of sites that have access to populations with high LD annual incidence is uncertain. This active, prospective surveillance study assesses annual LD incidence at general practice (GP)/primary care sites, allowing for phase III site vetting and better characterisation of LD burden in selected regions for study size calculations. METHODS AND ANALYSIS: This burden of Lyme disease (BOLD) study will assess LD incidence overall and by site at 15 GP/primary care practices in endemic areas of 6 European countries from Spring 2021 to December 2022 and will be summarised with counts (n), percentages (%) and associated 95% CIs. Suspected LD cases identified from site's practice panels are documented on screening logs, where clinical LD manifestations, diagnoses and standard of care diagnostic results are recorded. In the initial 12-month enrolment phase, suspected LD cases are offered enrolment. Participants undergo interview and clinical assessments to establish medical history, final clinical diagnosis, clinical manifestations and quality of life impact. Study-specific procedures include LD serology, skin punch biopsies and Lyme manifestation photographs. For every enrolled participant diagnosed with LD, 6-10 age-matched controls are randomly selected and offered enrolment for an embedded LD risk factor analysis. Persistent symptoms or post-treatment LD will be assessed at follow-up visits up to 2 years after initial diagnosis, while patients remain symptomatic. ETHICS AND DISSEMINATION: This study has been approved by all sites' local ethics committees. The results will be presented at conferences and published in peer-reviewed journals.

A tick-borne encephalitis virus vaccine based on the European prototype strain induces broadly reactive cross-neutralizing antibodies in humans.

After vaccination of humans with tick-borne encephalitis virus (TBEV) vaccine, the extent of cross-neutralization between viruses of the European, Far Eastern, and Siberian subtypes of TBEV and Omsk hemorrhagic fever virus (OHFV) was analyzed. Hybrid viruses that encode the TBEV surface proteins for representative viruses within all subtypes, and OHFV, were constructed using the West Nile virus (WNV) backbone as vector. These viruses allow for unbiased head-to-head comparison in neutralization assays because they exhibit the antigenic characteristics of the TBEV strains from which the surface proteins were derived and showed equivalent biologic properties in cell culture. Human serum samples derived from a TBEV vaccine trial were analyzed and revealed comparable neutralizing antibody titers against European, Far Eastern, and Siberian subtype viruses, indicating equally potent cross-protection against these TBEV strains and a somewhat reduced but still protective neutralization capacity against more distantly related viruses, such as OHFV.

Seropersistence of tick-borne encephalitis antibodies, safety and booster response to FSME-IMMUN 0.5 ml in adults aged 18-67 years.

A clinical study was carried out to evaluate the persistence of tick-borne encephalitis (TBE) antibodies 2 and 3 years after a primary vaccination series (three-dose regimen), and to assess the antibody response to a booster vaccination with FSME-IMMUN. Volunteers (N = 347, 18-67 years) who had received two doses of either FSME-IMMUN or Encepur adults and a third vaccination with FSME-IMMUN were enrolled. Seropositivity rates were assessed by ELISA and neutralization test (NT). After the primary series, seropositivity rates were 99.1% as determined by ELISA and 100% by NT, decreasing to 85% and 96.8% in the first two years and to 88.7% and 95.4% after 3 years. Following booster vaccination, 100% of subjects were seropositive. Age was the only variable with a significant influence on the probability of remaining TBE seropositive 2 or 3 years after the third vaccination. In subjects aged 18-50 years, the pre-booster seropositivity rate was higher (88.7% and 92.3% after 2 and 3 years, respectively) than in those aged 51-67 years (65.5% and 70.9% after 2 and 3 years, respectively). Adverse events after booster vaccination occurred with a low frequency and were predominantly mild. An annual TBE antibody decline rate of 0.58 (based on NT) was estimated to lead to antibody titer decrease from e.g., 260 to 45.6 after 3 years. To conclude, a booster vaccination with FSME-IMMUN, administered 3 years after primary vaccination, is well tolerated and induces a

Safety and immunogenicity of two different doses of a Vero cell-derived, whole virus clade 2 H5N1 (A/Indonesia/05/2005) influenza vaccine.

A successful vaccine development strategy for areas with clustered H5N1 events requires conduct of vaccine trials in potentially non-naïve subjects and evaluation of post-vaccination responsiveness. An open-label, randomized, phase I/II study therefore assessed the immunogenicity and safety of two different dose levels of an inactivated, non-adjuvanted, whole virus clade 2.1 (A/Indonesia/05/2005) H5N1 Vero cell-derived influenza vaccine in healthy adults (21-45 years) from a region where the virus has been circulating (Hong Kong) as well as Singapore. Subjects (N=110) were randomized 1:1 to receive two vaccinations with either 3.75 µg or 7.5 µg H5N1 haemagglutinin antigen 21 days apart. Safety, immunogenicity (microneutralization [MN] and single radial haemolysis [SRH] at baseline and post-vaccination) and cross-reactivity against a heterologous clade 1 strain (A/Vietnam/1203/2004) of the vaccine were assessed. Pre-existing immunity to the vaccine strain was 14% which is higher than previously reported for these regions. Two vaccinations with either vaccine formulation induced high seroprotection rates (MN titre ≥ 1:20) against the vaccine strain A/Indonesia/05/2005: 82.7% and 86.5% in the 3.75 µg and 7.5 µg dose groups. Seroconversion rates and fold increase exceeded the CPMP criterion of >40% and >2.5 for MN and SRH in both dose groups after the second vaccination, while the seroprotection rate in the 7.5 µg dose group determined by SRH was only marginally lower (69.2%) than the CPMP criterion of >70%. Thus, 11 of 12 CHMP criteria were fulfilled. A cross-reactive antibody response against the heterologous A/Vietnam/1203/2004 strain was demonstrated after the second vaccination (>21% by MN and ≥ 25% by SRH). Persistence of antibodies against the vaccine strain was also demonstrated 6 months after the first vaccination, indicating that a booster vaccination would be effective in those who have received two priming doses. No serious adverse events were reported. The H5N1 influenza vaccine against clade 2.1 strain A/Indonesia/05/2005 was well tolerated and immunogenic after two vaccinations, and induced a cross-neutralizing antibody response, with no dose effect.

A non-adjuvanted whole-virus H1N1 pandemic vaccine is well tolerated and highly immunogenic in children and adolescents and induces substantial immunological memory.

This phase 1/2 open-label, randomized clinical study investigated the safety and immunogenicity of a non-adjuvanted, whole virus, Vero cell-derived H1N1 pandemic influenza vaccine (A/H1N1/California/07/2009) in children and adolescents (6 months to 17 years). Subjects were stratified by age (6-11 months, 12-35 months, 3-8 years, 9-17 years) to receive two vaccinations 21 days apart of either the 3.75 µg or 7.5 µg dose. A booster with a licensed trivalent seasonal (2010/2011) influenza vaccine was administered one year after the first vaccination to a subgroup that had previously received the 7.5 µg dose. A single vaccination with the 7.5 µg dose induced high seroprotection rates in all subjects, namely: 88.0% (9-17 years); 68.0% (3-8 years); 42.9% (12-35 months); and 50.0% (6-11 months). Following a second vaccination, seroprotection rates ranged from 84.2% to 100%. GMTs after two vaccinations with the 7.5 µg dose (as determined by HI) were also substantial: reaching 210.0 (9-17 years), 196.2 (3-8 years), 118.9 (12-35 months) and 99.6 (6-11 months). Antibody persistence was demonstrated at 6 months (GMTs ranging from 65.6 to 212.8 with the 7.5 µg dose) and at 12 months (GMTs ranging from 33.6 to 124.1 with the 7.5 µg dose) after primary vaccination. The booster vaccination induced a strong response to the A/California/07/2009 strain, reaching 100% seroprotection in all age groups, with GMTs ranging from 640.0 to 886.3. The vaccine was well tolerated, inducing low adverse reaction rates (overall fever rate: 6% after the first vaccination; 7% after the second vaccination), even in young children. These data confirm that the H1N1 whole-virus Vero cell-derived pandemic influenza vaccine is suitable for use in children and adolescents; a 2-dose primary vaccination induces a memory response in a naïve population that can be effectively boosted with the A/H1N1/California/07/2009 component of a seasonal influenza vaccine. ClinicalTrials.gov Identifier: NCT00976469.

Pre-vaccination immunity and immune responses to a cell culture-derived whole-virus H1N1 vaccine are similar to a seasonal influenza vaccine.

BACKGROUND: Immune responses to novel pandemic influenza vaccines may be influenced by previous exposure to antigenically similar seasonal strains. METHODS: An open-label, randomized, phase I/II study was conducted to assess the immunogenicity and safety of a non-adjuvanted, inactivated whole-virus H1N1 A/California/07/2009 vaccine. 408 subjects were stratified by age (18-59 and >60 years) and randomized 1:1 to receive two vaccinations with either 3.75 or 7.5 µg hemagglutinin antigen 21 days apart. Safety, immunogenicity and the influence of seasonal influenza vaccination and antibody cross-reactivity with a seasonal H1N1 strain was assessed. RESULTS: A single vaccination with either dose induced substantial increases in H1N1 A/California/07/2009 hemagglutination inhibition (HI) and neutralizing (MN) antibody titers in both adult and elderly subjects. A single 7.5 µg dose induced seroprotection rates of 86.9% in adults and 75.2% in elderly subjects. Two 7.5 µg vaccinations induced seroprotection rates in adult and elderly subjects of 90.9% and 89.1%, respectively. The robust immune response to vaccination was confirmed by analyses of neutralizing antibody titers. Both HI and MN antibodies persisted for ≥ 6 months post-vaccination. Between 34% and 49% of subjects had seroprotective levels of H1N1 A/California/07/2009 antibodies at baseline. Higher baseline HI titers were associated with receipt of the 2008-09 or 2009-10 seasonal influenza vaccine. High baseline A/California/07/2009 neutralizing antibody titers were also associated with high baseline titers against A/New Caledonia/20/99, a seasonal H1N1 strain which circulated and was included in the seasonal vaccine from 2000-01 to 2006-07. Pre-adsorption with A/H1N1/New Caledonia/20/99 antigen reduced A/H1N1/California/07/2009 baseline titers in 55% of tested sera. The vaccine was well tolerated with low rates of fever. CONCLUSIONS: A whole-virus H1N1 A/California/07/2009 vaccine was safe and well tolerated and a single dose induced substantial immune responses similar to seasonal influenza vaccines, probably due to immunological priming by previous seasonal influenza vaccines or infections.

Prevention of tick-borne encephalitis by FSME-IMMUN vaccines: review of a clinical development programme.

The need for highly effective tick-borne encephalitis (TBE) vaccines has increased globally due to a variety of factors including climate, social, economic and demographic changes, which are thought to have promoted the expansion of the endemic region of TBE viruses. The first TBE vaccine, FSME-IMMUN Inject, was introduced in the 1970s and has been continually improved since then to enhance both its safety and immunogenicity. The current formulation was established in 2001 and is marketed as FSME-IMMUN. This review summarizes findings of the clinical development programme since 2001 regarding determination of the optimal dose, conventional and rapid vaccination schedules, vaccination in adults, the elderly and special patient populations, safety, immunogenicity, and immunopersistence in adults and children, comparison of FSME-IMMUN with another commercially available TBE vaccine as well as post-marketing vaccination outcome. This successful research programme demonstrated the strong immunogenicity and continued safety of the FSME-IMMUN vaccine, which is further confirmed by the performance reported under field conditions.

Tolerability of modified tick-borne encephalitis vaccine FSME-IMMUN "NEW" in children: results of post-marketing surveillance.

A new, highly purified, inactivated tick-borne encephalitis (TBE) vaccine FSME-IMMUN "NEW" has been developed by Baxter using a production virus seed derived from chick embryo cells instead of mouse brain. In clinical trials, the vaccine was shown to be highly immunogenic and well tolerated in adults and children. Following licensure in 2001, the tolerability of half the adult dose of FSME-IMMUN "NEW" (1.2 microg antigen/0.25 ml) was investigated in a post-marketing surveillance in 1899 children aged 6 months to 12 years. Rectal body temperature was measured daily for 3 days after the first vaccination. An overall fever rate of 20.3% (95% CI=18.5; 22%) was observed, which was mostly mild in nature (>38.0 to

Randomized, phase II dose-finding studies of a modified tick-borne encephalitis vaccine: evaluation of safety and immunogenicity.

Two clinical studies were conducted to identify the optimal dose of a modified tick-borne encephalitis (TBE) vaccine (FSME-IMMUN "new") in adults. A prospective, randomised, phase II, double-blind dose-finding study with the FSME-IMMUN "new" vaccine was performed in volunteers aged 16-65 years (n=405) to evaluate the immunogenicity and safety of two vaccinations with three vaccine doses (0.6, 1.2 and 2.4microg antigen). The safety and immunogenicity of the third vaccination were investigated in a follow-up study on the same study population. Antibody response to vaccination was assessed by enzyme-linked immunosorbent assay (ELISA) and, after the third vaccination, by neutralisation test (NT). Seroconversion rates (ELISA) in the different dose groups (0.6, 1.2 and 2.4 microg) were 85.1, 96.2 and 97.0%, respectively, after the second vaccination, which 73% of the volunteers received only 21 days after the first vaccination. Seroconversion rates after the third vaccination were 96, 99.2 and 100% (ELISA) as well as 77, 93 and 96.6% (NT) with the 0.6, 1.2 and 2.4 microg doses, respectively. No unexpected AEs or vaccine-related serious adverse events (SAE) were observed during either study. Local and systemic reactions were mainly mild and not dose-dependent, with an overall fever rate of <1% after the first vaccination. The 2.4 microg dose is the optimal dose for the FSME-IMMUN "new" preparation in adults, as it was found to: (1) be non-inferior to the 1.2 microg dose with respect to fever rate after the first vaccination; (2) induce the highest seroconversion rate; and (3) be well-tolerated with respect to local and systemic reactions. The results of both studies demonstrate that the FSME-IMMUN "new" vaccine is safe and highly immunogenic in adults.