Reduced Respiratory Syncytial Virus Load, Symptoms, and Infections: A Human Challenge Trial of MVA-BN-RSV Vaccine.

BACKGROUND: Respiratory syncytial virus (RSV) causes significant disease burden in older adults. MVA-BN-RSV is a novel poxvirus-vectored vaccine encoding internal and external RSV proteins. METHODS: In a phase 2a randomized double-blind, placebo-controlled trial, healthy participants aged 18 to 50 years received MVA-BN-RSV or placebo, then were challenged 4 weeks later with RSV-A Memphis 37b. Viral load was assessed from nasal washes. RSV symptoms were collected. Antibody titers and cellular markers were assessed before and after vaccination and challenge. RESULTS: After receiving MVA-BN-RSV or placebo, 31 and 32 participants, respectively, were challenged. Viral load areas under the curve from nasal washes were lower (P = .017) for MVA-BN-RSV (median = 0.00) than placebo (median = 49.05). Total symptom scores also were lower (median = 2.50 and 27.00, respectively; P = .004). Vaccine efficacy against symptomatic, laboratory-confirmed or culture-confirmed infection was 79.3% to 88.5% (P = .022 and .013). Serum immunoglobulin A and G titers increased approximately 4-fold after MVA-BN-RSV vaccination. Interferon-γ-producing cells increased 4- to 6-fold after MVA-BN-RSV in response to stimulation with the encoded RSV internal antigens. Injection site pain occurred more frequently with MVA-BN-RSV. No serious adverse events were attributed to vaccination. CONCLUSIONS: MVA-BN-RSV vaccination resulted in lower viral load and symptom scores, fewer confirmed infections, and induced humoral and cellular responses. CLINICAL TRIALS REGISTRATION: NCT04752644.

One- and Two-Dose Vaccinations With Modified Vaccinia Ankara-Bavarian Nordic Induce Durable B-Cell Memory Responses Comparable to Replicating Smallpox Vaccines.

BACKGROUND: Although modified vaccinia Ankara-Bavarian Nordic (MVA-BN) vaccination is approved for smallpox and monkeypox prevention, immunological persistence and booster effects remain undescribed. METHODS: Participants naive to smallpox vaccination were randomized to 1 dose MVA-BN (1×MVA, n = 181), 2 doses MVA-BN (2×MVA, n = 183), or placebo (n = 181). Participants with previous smallpox vaccination received 1 MVA-BN booster (HSPX, n = 200). Subsets of the formerly naive groups (approximately 75 each) received an MVA-BN booster 2 years later. RESULTS: Neutralizing antibody (nAb) geometric mean titers (GMTs) increased from 1.1 (baseline, both naive groups) to 7.2 and 7.5 (week 4, 1×MVA and 2×MVA, respectively), and further to 45.6 (week 6, 2×MVA after second vaccination). In HSPX, nAb GMT rapidly increased from 21.6 (baseline) to 175.1 (week 2). At 2 years, GMTs for 1×MVA, 2×MVA, and HSPX were 1.1, 1.3, and 10.3, respectively. After boosting in the previously naive groups, nAb GMTs increased rapidly in 2 weeks to 80.7 (1×MVA) and 125.3 (2×MVA), higher than after primary vaccination and comparable to boosted HSPX subjects. Six months after boosting, GMTs were 25.6 (1×MVA) and 49.3 (2×MVA). No safety concerns were identified. CONCLUSIONS: Anamnestic responses to boosting without sustained high nAb titers support presence of durable immunological memory following primary MVA-BN immunization. Clinical Trials Registration. NCT00316524 and NCT00686582.

Real-world safety data for MVA-BN: Increased frequency of syncope following intradermal administration for immunization against mpox disease.

BACKGROUND: MVA-BN vaccine (Jynneos, Imvamune, Imvanex) was used widely in the 2022 mpox outbreak. This experience provides real-world evidence about the vaccine's safety, particularly regarding intradermal use. METHODS: Bavarian Nordic's global safety database was searched for all adverse events following immunization (AEFIs) with MVA-BN. AEFI numbers were compared among administration routes. Selected events and administered doses were graphed over the mpox outbreak period. RESULTS: A total of 9585 AEFIs have been reported. The rate of myocarditis or pericarditis was <1 per 100,000 doses administered. Eighty-nine cases of syncope, fainting, or loss of consciousness were reported. This number rose after the August 2022 US emergency use authorization for intradermal administration, as did the proportion of all syncope AEFIs reported following intradermal administration (78,7 %). CONCLUSION: Real-world data from large-scale administration of MVA-BN has confirmed the vaccine's established safety profile when administered subcutaneously. Intradermal administration is likely associated with increased syncopal event frequency.

The Quest for a Respiratory Syncytial Virus Vaccine for Older Adults: Thinking beyond the F Protein.

Respiratory syncytial virus (RSV) is a common cause of paediatric respiratory tract infection and causes a significant health burden in older adults. Natural immunity to RSV is incomplete, permitting recurrent symptomatic infection over an individual's lifespan. When combined with immunosenescence, this increases older adults' susceptibility to more severe disease symptoms. As RSV prophylaxis is currently limited to infants, older adults represent an important target population for RSV vaccine development. The relationship between RSV and our immune systems is complex, and these interactions require deeper understanding to tailor an effective vaccine candidate towards older adults. To date, vaccine candidates targeting RSV antigens, including pre-F, F, G (A), G (B), M2-1, and N, have shown efficacy against RSV infection in older adults in clinical trial settings. Although vaccine candidates have demonstrated robust neutralising IgG and cellular responses, it is important that research continues to investigate the RSV immune response in order to further understand how the choice of antigenic target site may impact vaccine effectiveness. In this article, we discuss the Phase 3 vaccine candidates being tested in older adults and review the hurdles that must be overcome to achieve effective protection against RSV.

Perceptions of tick-borne encephalitis risk: a survey of travellers and travel clinics from Canada, Germany, Sweden and the UK.

Background: While the worldwide endemicity of tick-borne encephalitis (TBE) has been increasing, a lack of awareness of the risks of this life-threatening disease may be leading to an underutilization of preventive measures among travellers to TBE-endemic regions. This study's objectives were to assess travellers' awareness of TBE and advice-seeking attitudes, and to evaluate practices of travel clinics regarding pre-travel advice. Methods: We used an online questionnaire to identify individuals aged 18-65 years residing in the UK, Germany, Canada and Sweden, who had travelled to TBE-endemic countries between 2013 and 2016. This sample was defined as the visit-risk sample. Of these, the first 375 respondents who reported that they had engaged in pre-defined at-risk activities (e.g. hiking in forests) were asked to complete an additional online survey and were included in the activity-risk sub-sample. We also used an online/phone questionnaire to interview travel clinic personnel. Results: The TBE visit-risk sample included 4375 individuals; 69% had heard of the disease and 32% had heard of a TBE vaccine. Before travelling, travellers most commonly sought information online (26%); fewer travellers consulted family doctors (8%) or travel clinics (5%). In the activity-risk sample, 79% of the travellers were aware of at least one correct TBE prevention measure; however, only 15% reported being vaccinated within the past 3 years, with 11% of vaccinated travellers doing so following a clinic's recommendation. One hundred and eighty travel clinic representatives responded and reported that TBE vaccination was recommended to an average of 61% of travellers to endemic regions. Vaccination-reminder services such as follow-up appointments, e-mail and text reminders were offered by 50% of the clinics. Conclusions: There is a need to increase awareness of the risk and prevention of TBE among travellers to endemic countries, and travel clinics could play an important role in this process. 5975671594001tay062media15975671594001.

Perceptions of rabies risk: a survey of travellers and travel clinics from Canada, Germany, Sweden and the UK.

Background: Extensive global experience shows that rabies pre-exposure prophylaxis (PrEP) through vaccination is effective and well tolerated, yet many travellers opt not to be vaccinated when travelling to rabies-endemic countries. Previous research has identified several factors influencing the choices travellers make to reduce the risk of rabies, including cost, time constraint and perspective on the importance of vaccination. The objectives of this study were to assess travellers' awareness of rabies and advice-seeking attitudes and to evaluate travel clinics practices regarding rabies pre-travel advice. Methods: We surveyed individuals aged 18-65 years residing in the UK, Germany, Canada and Sweden who had travelled to rabies-endemic countries between 2013 and 2016 and defined this as the rabies visit-risk sample. The first 850 respondents from the visit-risk sample who had undertaken pre-defined at-risk activities (e.g. contact with animals during the trip) completed an additional 15-min online questionnaire and were included in the activity-risk subsample. We also interviewed travel clinic personnel using a 25-min online or phone questionnaire. Results: The visit-risk sample included 4678 individuals. Many sought pre-travel health information online (33%) or talked to a family doctor (24%). Within the activity-risk subsample, 83% of travellers were aware of at least a few basic facts about rabies, and 84% could identify at least one correct rabies prevention measure; 49% were aware of a rabies vaccine, however, only 8% reported receiving PrEP vaccination within the past 3 years. Among 180 travel clinic respondents, 21% reported recommending PrEP against rabies to all travellers to rabies-endemic countries. Travel clinics estimated that 81% of travellers complete their travel vaccination schedules and reported sending reminders by e-mails (38%), text (38%), phone calls (37%) or by using vaccination cards (37%). Conclusions: These findings suggest that although travellers had frequently heard of rabies, awareness of the risks of this serious infectious disease was relatively low. 5975671594001tay062media15975671594001.

German travelers' preferences for travel vaccines assessed by a discrete choice experiment.

BACKGROUND: Many travelers to regions with endemic infectious diseases do not follow health authorities' recommendations regarding vaccination against vaccine-preventable infectious diseases, before traveling. The determinants of individual travelers' decisions to vaccinate before traveling are largely unknown. This study aimed to provide this information using a discrete choice experiment (DCE) administered to four types of German travelers: (1) business travelers; (2) travelers visiting friends and relatives (VFR); (3) leisure travelers; and (4) backpackers. METHODS: A DCE survey was developed, pretested and administered online. It included a series of choice questions in which respondents chose between two hypothetical vaccines, each characterized by four disease attributes with varying levels describing the of risk, health impact, curability and transmissibility of the disease they would prevent (described with four disease attributes with varying levels of risk, health impact, curability and transmissibility), and varying levels of four vaccine attributes (duration of protection, number of doses required, time required for vaccination, and vaccine cost). A random-parameters logit model was used to estimate the importance weights each traveler type placed on the various attribute levels. These weights were used to calculate mean monetary equivalents (MMEs) of changes in each attribute (holding all others constant) and of hypothetical disease-vaccine combinations. RESULTS: All traveler types' choices indicated that they attached the greatest importance to the risk and health impact of disease and to the vaccine cost whereas the other disease and vaccine attributes were less important for their decisions about travel vaccines. An option of not choosing any of the vaccine-pairs presented was rarely selected indicating that travelers' generally prefer to be vaccinated rather than not. The MMEs of changes in vaccine attributes indicated a very high variability between the individual travelers within each type. CONCLUSIONS: The travelers' responses indicated strong preferences for selecting vaccination rather than opting out of vaccination, and disease risk, health impact and vaccine cost were the most important features for vaccine choice.

Impact of universal mass vaccination with monovalent inactivated hepatitis A vaccines - A systematic review.

The WHO recommends integration of universal mass vaccination (UMV) against hepatitis A virus (HAV) in national immunization schedules for children aged ≥1 year, if justified on the basis of acute HAV incidence, declining endemicity from high to intermediate and cost-effectiveness. This recommendation has been implemented in several countries. Our aim was to assess the impact of UMV using monovalent inactivated hepatitis A vaccines on incidence and persistence of anti-HAV (IgG) antibodies in pediatric populations. We conducted a systematic review of literature published between 2000 and 2015 in PubMed, Cochrane Library, LILACS, IBECS identifying a total of 27 studies (Argentina, Belgium, China, Greece, Israel, Panama, the United States and Uruguay). All except one study showed a marked decline in the incidence of hepatitis A post introduction of UMV. The incidence in non-vaccinated age groups decreased as well, suggesting herd immunity but also rising susceptibility. Long-term anti-HAV antibody persistence was documented up to 17 y after a 2-dose primary vaccination. In conclusion, introduction of UMV in countries with intermediate endemicity for HAV infection led to a considerable decrease in the incidence of hepatitis A in vaccinated and in non-vaccinated age groups alike.

Should adults with diabetes mellitus be vaccinated against hepatitis B virus? A systematic review of diabetes mellitus and the progression of hepatitis B disease.

Despite the burden of diabetes mellitus (DM), little is known about the role of this and other metabolic syndromes on the severity of hepatitis B virus (HBV) chronicity and liver disease progression. The value of hepatitis B vaccination and its impact on liver diseases and HCC has been largely demonstrated, adult vaccination coverage is however suboptimal and DM diagnosis represents an opportunity for the HCP to discuss hepatitis B and other adult vaccinations. We performed a systematic literature search to identify studies (January 2000 to January 2017) describing liver disease progression among patients with HBV by DM status. Risk factors were assessed including the relationship between HBV and non-alcoholic steatohepatitis (NASH). Data were extracted systematically and assessed descriptively. Twenty articles described liver disease progression and one article evaluated NASH among subjects with HBV by DM status. Fourteen articles reported that DM as a predictor for the outcome, including delayed seroclearance, cirrhosis, hepatocellular carcinoma, transplant/mortality and death, whereas no association on liver outcomes was found in 7 studies. In summary, our review suggests that DM is associated with the progression of severe liver outcomes in adults with HBV, although more studies are needed to understand the benefits of HBV vaccination in adults with DM and liver-diseases.

The immunogenicity and safety of GSK's recombinant hepatitis B vaccine in adults: a systematic review of 30 years of experience.

INTRODUCTION: Engerix B (GSK HepB, GSK, Belgium) was the first recombinant hepatitis B virus vaccine to be licensed, and marked its 30th anniversary in 2016. Vaccination of adult populations against HBV is usually implemented on a risk-based approach with varying degrees of success. Confirmation of ongoing vaccine effectiveness requires monitoring the performance of HBV immunization as reported in individual studies, using systematic methods. Areas covered: We conducted a systematic review of the literature to summarize 30 years of immunogenicity and safety data for GSK HepB in adult populations. Expert commentary: Primary 3-dose vaccination of healthy individuals is generally associated with seroprotection rates of 90% or more, although seroprotection decreases with older age. Accelerated 0, 1, 2-month or 0, 7 and 21-day schedules require the recommended booster dose to achieve similar rates of seroprotection. Lower rates of seroprotection were also observed in adults with underlying chronic disease and with a weakened immune system. GSK HepB had a clinically acceptable safety profile in all of the populations studied, including individuals with underlying co-morbidities and immunosuppression. GSK HepB will continue to contribute to global HBV control for the foreseeable future. Further investigation is needed into how to optimize seroprotection in less immune-competent groups.

The immunogenicity of GSK's recombinant hepatitis B vaccine in children: a systematic review of 30 years of experience.

INTRODUCTION: The World Health Organization recommends hepatitis B virus (HBV) vaccines to be included in national immunization schedules everywhere, and has adopted the strategic goal of halting viral hepatitis as a major public health threat by 2030, under which vaccination plays a major role. Engerix™ B (GSK HepB, GSK, Belgium) was the first recombinant HBV vaccine to be licensed, and marked its 30th anniversary in 2016. Areas covered: We conducted a systematic review of the literature summarizing 30 years of immunogenicity and safety data for GSK HepB in children and adolescents. Expert commentary: Primary 3-dose vaccination of healthy infants and children, including infants born to HBsAg-positive mothers, using the standard 0, 1, 6 month schedule was associated with seroprotection rates ≥96.0%. In high-risk infants, vaccine efficacy at year 5 was 96.0% after 3-dose priming in infancy and immunoglobulin at birth. Lower seroprotection rates were observed in children with severe underlying disease including human immunodeficiency virus infection and cancer. GSK HepB had a clinically acceptable safety profile in all of the populations studied. HBV vaccines have demonstrated long-term impacts on rates of fulminant hepatitis, chronic liver disease and hepatocellular carcinoma. GSK HepB will continue to contribute to global HBV control for the foreseeable future.

Systematic literature review comparing rapid 3-dose administration of the GSK tick-borne encephalitis vaccine with other primary immunization schedules.

INTRODUCTION: Tick-borne encephalitis (TBE), which is endemic across large regions of Europe and Asia, is most effectively prevented through vaccination. Three-dose primary TBE vaccination schedules are either rapid (0,7,21-days) or conventional (0,28-84-days, 9-12-months). The second dose can also be administered at 14 days for faster priming and sero-protection). Areas covered: We used a three-step selection process to identify 21 publications comparing the immunogenicity and/or safety of different schedules. Expert commentary: Priming with two or three TBE vaccine doses was highly immunogenic. After conventional priming (0-28 days), 95% adults and ≥95% children had neutralization test (NT) titers ≥10 at 14 days post-dose-2 compared with 92% adults and 99% children at 21 days post-dose-3 (rapid schedule). Most subjects retained NT titers ≥10 at day 300. A single booster dose induced a strong immune response in all subjects irrespective of primary vaccination schedule or elapsed time since priming. GMT peaked at 42 days post-dose-1 (i.e., 21 days post-dose 3 [rapid-schedule], or 14-28 days post-dose-2 [conventional-schedule]), and declined thereafter. Adverse events were generally rare and declined with increasing doses. In the absence of data to recommend one particular schedule, the regimen choice will remain at the physician's discretion, based on patient constraints and availability.

HAV & HBV vaccination among travellers participating in the National Health and Wellness Survey in five European countries.

BACKGROUND: A main cause of hepatitis A and B infections in European countries is travel to endemic countries. Most research on hepatitis vaccination among travellers from Europe has been conducted in airports or travel clinics, samples which potentially overrepresented frequent travellers. METHODS: 2102 respondents across France, Germany, Italy, Spain, and UK completed an internet-based questionnaire. Vaccination status, travel to endemic countries, and other characteristics were compared across frequent, occasional, and non-travellers. Logistic regressions tested association between vaccination and travel adjusting for potential confounders. RESULTS: Most respondents were occasional travellers (61%) and 24% were frequent travellers. Frequent travellers had 2.3-2.4 times the odds of being vaccinated relative to non-travellers, and odds of vaccination were 2.5-3.1 times higher among travellers to endemic areas relative to others (all p < .05). Frequent travellers were more aware of their vaccination status (HAV: 80% vs. 72%; HBV: 82% vs. 74%), though many who were vaccinated could not identify the number of injections to complete the series (47% vs. 29%) (all p < .05). CONCLUSION: Travel frequency and destination endemicity are associated with increased hepatitis A and B vaccination. The number of unvaccinated travellers and the lack of recall for the dosing schedule suggest the need to improve travellers' awareness and adherence to recommendations.

Immunogenicity, effectiveness and safety of combined hepatitis A and B vaccine: a systematic literature review.

BACKGROUND: Hepatitis A and B are two of the most common vaccine-preventable diseases and vaccination for Hepatitis A virus (HAV) and hepatitis B virus (HBV) is recommended for those at risk of contracting HAV and/or HBV through their occupation, travel or lifestyle. OBJECTIVE: To describe the vaccine efficacy, immunogenicity, effectiveness and safety of the combined vaccine against hepatitis A and hepatitis B. METHODS: A systematic review of the literature published between 1990 and 2015. RESULTS: Anti-HAV seropositivity rates ranged from 96.2% to 100% and anti-HBs seroprotection rates from 82% to 100%. Antibodies persisted up to 15 years and geometric mean concentration (GMC) remained above the seropositivity cut-off value for both. Anti-HAV and anti-HBs immune responses were lower in less immunocompetent individuals one month after completion of the immunization schedule. The safety profiles of Twinrix(TM) and monovalent hepatitis A and B vaccines were similar. CONCLUSION: The vaccine offers satisfactory long-term immunogenicity rates, expected duration of protection and safety profile similar to the monovalent hepatitis A or B vaccines.

Pre-travel advice, attitudes and hepatitis A and B vaccination rates among travellers from seven countries†.

BACKGROUND: Knowledge about the travel-associated risks of hepatitis A and B, and the extent of pre-travel health-advice being sought may vary between countries. METHODS: An online survey was undertaken to assess the awareness, advice-seeking behaviour, rates of vaccination against hepatitis A and B and adherence rates in Australia, Finland, Germany, Norway, Sweden, the UK and Canada between August and October 2014. Individuals aged 18-65 years were screened for eligibility based on: travel to hepatitis A and B endemic countries within the past 3 years, awareness of hepatitis A, and/or combined hepatitis A&B vaccines; awareness of their self-reported vaccination status and if vaccinated, vaccination within the last 3 years. Awareness and receipt of the vaccines, sources of advice, reasons for non-vaccination, adherence to recommended doses and the value of immunization reminders were analysed. RESULTS: Of 27 386 screened travellers, 19 817 (72%) were aware of monovalent hepatitis A or combined A&B vaccines. Of these 13 857 (70%) had sought advice from a healthcare provider (HCP) regarding combined hepatitis A&B or monovalent hepatitis A vaccination, and 9328 (67%) were vaccinated. Of 5225 individuals eligible for the main survey (recently vaccinated = 3576; unvaccinated = 1649), 27% (841/3111) and 37% (174/465) of vaccinated travellers had adhered to the 3-dose combined hepatitis A&B or 2-dose monovalent hepatitis A vaccination schedules, respectively. Of travellers partially vaccinated against combined hepatitis A&B or hepatitis A, 84% and 61%, respectively, believed that they had received the recommended number of doses. CONCLUSIONS: HCPs remain the main source of pre-travel health advice. The majority of travellers who received monovalent hepatitis A or combined hepatitis A&B vaccines did not complete the recommended course. These findings highlight the need for further training of HCPs and the provision of reminder services to improve traveller awareness and adherence to vaccination schedules.