Expert Review of Vaccines最新文献

Background: Vaccine hesitancy hinders optimal immunization coverage with fear of adverse events following immunization (AEFI) as a key driver. This study examines how robust district-level AEFI management capacity alleviates vaccine hesitancy among guardians of 0-6-year-olds in Chongqing, China.

Research design and methods: A cross-sectional survey was conducted from January to March 2023. Guardians were recruited via multistage stratified sampling. Two-level multivariate modeling and structural equation modeling (SEM) were employed to explore direct and indirect effects of AEFI management capacity on hesitancy.

Results: Among 2664 valid samples, the mean hesitancy score was 21.9 ± 4.5, with 19.5% self-reporting hesitancy. AEFI incident response capability (β = -1.087, 95% CI: -2.053~-0.121), approval of district AEFI committees (β = -1.202, 95% CI: -1.839~-0.565) and higher vaccination knowledge (β = -0.377, 95% CI: -0.571~-0.183) were negatively correlated with hesitancy. SEM further demonstrated that district-level AEFI management capacity indirectly decreases the guardians' hesitancy by improving their approval of AEFI committees (β = 0.183, 95% CI: 0.093 ~ 0.284).

Conclusions: Robust district AEFI management and higher vaccination knowledge alleviate guardians' hesitancy. Targeted interventions can boost trust and coverage. These findings provide actionable insights for refining immunization policies and practice in China and other countries facing similar challenges.

Introduction: Lyme disease is caused by the tick-borne spirochete pathogen Borrelia burgdorferi sensu lato (s.l.). Outer surface protein A (OspA) is expressed by B. burgdorferi s.l. while in the tick and antibodies against OspA introduced into the tick with the bloodmeal can prevent transmission. OspA-based vaccines have been validated in people, however, there are currently no available human Lyme disease vaccines. Hexavalent OspA vaccine VLA15 is designed to cover the dominant B. burgdorferi s.l. genospecies causing disease in North America and Europe and is currently the most advanced candidate human Lyme disease vaccine in clinical development.

Areas covered: A historical retrospective of the discovery and evolving burden of Lyme disease is covered, as well as relevant aspects of the vector biology, preclinical research underpinning development of VLA15, and its clinical development to date.

Expert opinion: Lyme disease has expanded over the past two decades in both incidence and geographic footprint and is anticipated to continue to increase in the future due to changing climate and human encroachment into wildlife areas. VLA15 is currently in the last stage of clinical development, and if found to be safe and efficacious, may offer an important prophylactic modality for prevention of Lyme disease.

Background: Individuals with chronic obstructive pulmonary disease (COPD) face increased risk of severe respiratory syncytial virus (RSV)-related outcomes. We assessed the uptake of adjuvanted-RSVPreF3 and its effectiveness against RSV hospitalization in such individuals.

Research design and methods: We assembled a Danish nationwide cohort of individuals aged ≥ 60 years with COPD during the 2024/25 RSV season. Vaccinated and unvaccinated individuals were matched using exact and propensity score matching resulting in balanced groups. Individuals were followed from 21 days post-vaccination until the earliest of event, end of data availability, migration, RSV vaccination, or death. Vaccine effectiveness was estimated as (1 - incidence rate ratio [IRR]) x 100, where IRRs were calculated using observed event counts and accumulated person-time. Confidence intervals (CIs) were based on Poisson distributions.

Results: Among 126,249 eligible individuals, 7,448 (5.9%) received adjuvanted-RSVPreF3. RSV hospitalization rates per 100,000 person-years were 0.0 (95% CI: 0.0-58.0) for vaccinated individuals and 200.6 (165.6 - 240.8) for unvaccinated individuals, yielding an effectiveness of 100.0% (71.1-100.0). Incidences of other RSV-related outcomes were lower among vaccinated individuals.

Conclusions: Adjuvanted-RSVPreF3 is highly effective in preventing RSV hospitalization in individuals aged ≥60 years with COPD. Disease outcomes could be improved by incorporating RSV vaccination into routine COPD management.

Introduction: Next-generation COVID-19 vaccines hold promise to reduce severe outcomes in populations most at risk. While the original mRNA COVID-19 vaccine, mRNA-1273, targets the full-length SARS-CoV-2 spike protein, mRNA-1283 is a novel next-generation mRNA COVID-19 vaccine that specifically targets immunodominant domains within the spike protein.

Areas covered: This review summarizes literature on the development of mRNA-1283, from its design and preclinical evaluation to phase 1-3 clinical trial findings, with a particular focus on immunogenicity and efficacy in at-risk populations, specifically older adults and adults with comorbidities. The potential public health impact of this next-generation vaccine is explored, along with ongoing challenges facing COVID-19 vaccination.

Expert opinion: Phase 1-3 clinical trials demonstrated that mRNA-1283 was well-tolerated and no safety concerns were identified. Furthermore, mRNA-1283 demonstrated higher point estimates of immunogenicity and relative vaccine efficacy than mRNA-1273, including among older adults and individuals with underlying conditions who are most susceptible to severe COVID-19. Initial modeling studies indicate that mRNA-1283 could prevent more hospitalizations than current COVID-19 vaccines. Evidence to date suggests that the novel next-generation mRNA-1283 vaccine holds promise to advance progress in reducing the ongoing burden of COVID-19 across vulnerable populations.

Background: To compare the adherence and efficacy between the 0 - 7 - 21-day and the 0 - 1 - 6-month hepatitis B virus (HBV) vaccination schedules among people who use drugs (PWUD) in China.

Research design and methods: A randomized controlled trial was conducted in 1261 HBV-susceptible PWUD from compulsory isolated detoxification centers (CIDCs) and methadone maintenance treatment (MMT) clinics in Xi'an. A 20 µg per-dose vaccine was used. HBV surface antibody (anti-HBs), surface antigen, and core antibody were tested at months 7, 15, and 22 after the first dose.

Results: Third-dose coverage was significantly higher in the 0 - 7 - 21-day group (74.40%) than in the 0 - 1 - 6-month group (51.58%, p < 0.001), mainly driven by participants from CIDCs (77.75% vs. 45.69%). Anti-HBs positive rates at months 7, 15, and 22 among participants who completed all three doses were significantly higher for the 0 - 1 - 6-month schedule (90.71%, 76.82%, and 67.35%) than for the 0 - 7 - 21-day schedule (74.23%, 49.40%, and 40.95%; all p < 0.001). HBV infection incidence was similar between schedules, but significantly different between vaccinees and non-vaccinees (p = 0.018).

Conclusions: The 0 - 7 - 21-day schedule substantially enhances three-dose completion in PWUD, but induces a notably weaker anti-HBs response and persistence. Schedules should be selected based on the management models for PWUD and their individual characteristics.

Clinical trial registration: Chinese Clinical Trial Registry (ChiCTR1900022403).

Background: Herpes zoster (HZ), caused by varicella-zoster virus, primarily affects the elderly. In May 2023, the first domestically produced live attenuated zoster vaccine was approved for use in adults aged 40 years or older in China.

Research design and methods: We conducted a self-controlled case series study to collect hospitalization events among 25,000 vaccinated adults (April 2020-December 2023, 5 regions) during the risk period (0-42 days) and the control period (72-162 days). Conditional Poisson regression models and conditional logistic regression models were applied to compare the risk of hospitalization.

Results: The rate ratio of hospitalization following immunization was 0·381 (0·323-0·450). Compared with those in control period, the incidence rates of the following hospitalization events decreased: RRs of 0·297 (0·203-0·435) for stroke, cerebrovascular, and nervous system diseases; 0·296 (0·205-0·527) for cardiovascular diseases; 0·183 (0·054-0·627) for genitourinary system diseases; 0·246 (0·155-0·391) for respiratory, thoracic, and mediastinal diseases; 0·238 (0·089-0·635) for diseases of eye and adnexal diseases; and 0·202 (0·053-0·766) for skin and subcutaneous tissue diseases.

Conclusions: This study confirms the safety of the live attenuated zoster vaccine, demonstrating that vaccination does not increase the risk of hospitalization and may even reduce the incidence of hospitalization.

Introduction: Prophylactic human papillomavirus vaccines have been in use in populations worldwide for nearly 20 years. Much has been learnt in relation to their effectiveness, safety, and how best to effectively implement them in populations to prevent cancer and other HPV-related diseases. Global challenges such as limited supply and the mismatch between those who can afford them and those with the greatest disease burden from cervical cancer have prevented optimal usage to date.

Areas covered: Here we identified recent papers and focus upon the accumulated evidence regarding HPV vaccine: i) effectiveness in preventing cancer and precancerous lesions, ii) safety in population usage, iii) trial evidence supporting registration of four newer vaccines, iv) progress in country-level introductions and coverage, and v) lessons learned in effective implementation.

Expert opinion: Reasons for optimism are many, with vast cumulative knowledge on impact, safety and implementation and accelerating HPV vaccine introductions, simplification of delivery and reduced costs through single dose approaches and supply constraints easing. However, considerable challenges remain in achieving and maintaining high and equitable global coverage, given the uncertainty in funding, risk to ongoing prioritization of health equity and to vaccine confidence in the current global public health environment.

Background: This study analyzed the health and economic outcomes of the 21-valent pneumococcal conjugate vaccine (PNEU-C-21; CAPVAXIVE®) compared to either PNEU-C-20 or PNEU-P-23. Cohorts in the cost-effectiveness analyses included vaccine-naïve 57- and 65-year-olds and vaccine-experienced 70-year-olds.

Research design and methods: A published Markov model simulated the movement of the Canadian population among four health states: healthy, pneumococcal disease (invasive pneumococcal disease and community-acquired pneumonia attributed to S. pneumoniae), post-meningitis sequelae, and death. The model was populated with published literature and publicly available databases and/or reports. Model inputs included demographic data, epidemiologic data, serotype distribution, vaccine effectiveness, costs, and health-related utilities. The model used a lifetime horizon and 1.5% discounting of costs and life years. Key outcomes included the following: cases, deaths, costs, and incremental cost-effectiveness ratios.

Results: The PNEU-C-21 strategy prevented substantially more cases and deaths when compared to the PNEU-C-20 or PNEU-P-23 strategies. For both vaccine-naïve cohorts, the ICERs were dominant for both PNEU-C-21 vs. PNEU-C-20 and PNEU-C-21 vs. PNEU-P-23; among adults aged 70 years, previously vaccinated with PNEU-P-23, PNEU-C-21 was dominant over PNEU-C-20.

Conclusions: These results demonstrate that PNEU-C-21 can prevent a substantial number of cases and deaths while remaining highly cost-effective over a range of inputs and scenarios in Canada.

Introduction: Neonatal sepsis, a systemic infection occurring in infants within their first 28 days of life, is a leading cause of mortality globally. The burden is especially severe in low- and middle-income countries (LMICs), where incidence and mortality rates are higher than in high-resource settings. Antimicrobial resistance, driven by multidrug-resistant pathogens prevalent in LMICs, further complicates its effective management. Vaccination offers a promising strategy to prevent infections caused by common neonatal sepsis pathogens, potentially reducing sepsis incidence and mitigating resistance.

Area covered: This review examines the burden of bacterial pathogens, specifically Group B Streptococcus (GBS), Klebsiella pneumoniae, and Escherichia coli, responsible for neonatal sepsis, drawing from a comprehensive literature search focusing on the last ten years across major databases. It provides an overview of vaccine candidates in clinical development, highlights innovative approaches in preclinical research, and discusses the key challenges associated with vaccine strategies preventing neonatal sepsis.

Expert opinion: Given the multivalency of vaccines for neonatal sepsis, innovative technologies are under investigation. Defining correlate of protections has been critical for GBS vaccine development, and may pave the way for vaccines against K. pneumoniae and E. coli. Novel regulatory and clinical strategies, including disease-based rather than pathogen-specific approaches, should be explored.