Effective Vaccine Research Articles

Epidemiological characteristics and survival analysis of pertussis in Quzhou

ABSTRACT Despite high vaccination coverage in high-income countries, recent reports of pertussis resurgence have heightened public concern about vaccine effectiveness and vaccination. Quzhou City has gradually transitioned from DTwP to DTaP vaccines, achieving a remarkable vaccination coverage rate of 99%. However, since 2024, there has been a significant surge in pertussis cases in Quzhou City. We collected data on pertussis cases, described the epidemiological characteristics of pertussis outbreaks in Quzhou City, examined pertussis vaccination history, and conducted a COX survival analysis. Pertussis cases reported in Quzhou City from January to April 2024 were far higher than those reported in previous years during the same period. Geographically, cases were concentrated in the central region and predominantly affected children under 9 years old, with a focus on the 5–9 age group. Survival analysis revealed that the risk of pertussis incidence increased by 2.84 times (HR = 2.87, 95% CI = 2.27 ~ 3.63) when comparing self-paid vaccines to free vaccines. The pertussis situation in Quzhou City remains critical, emphasizing the need for enhanced immunization strategies and further optimization of pertussis immunization protocols.

Protective Impact of Influenza Vaccination on Healthcare Workers

Background: Influenza vaccine uptake among healthcare workers is crucial for preventing influenza infections, yet its effectiveness needs further investigation. Objectives: This prospective observational study aimed to assess the protective effect of influenza vaccination among healthcare workers in Shenzhen. Methods: We enrolled 100 participants, with 50 receiving the 2023–2024 quadrivalent influenza vaccine (QIV) and 50 serving as unvaccinated controls. Epidemiological data were collected when the participants presented influenza-like illness. Serum samples were collected at three time points (pre-vaccination and 28 and 180 days after vaccination). Hemagglutination inhibition (HI) assay was performed against the strains included in the 2023–2024 QIV (H1N1, H3N2, BV and BY strains) to assess antibody protection levels. Demographics comparisons revealed no significant differences between the vaccinated and control groups (p > 0.05), ensuring group comparability. Results: The incidence of influenza-like illness was significantly lower in the vaccinated (18%) compared to the control group (36%; p = 0.046; OR = 0.39; 95% CI: 0.15 to 0.98). The vaccinated group also exhibited a higher rate of consecutive two-year vaccinations (48% vs. 24% in the control group, p < 0.05). Additionally, the vaccinated healthcare workers were more inclined to recommend vaccination to their families (80% vs. 48%, p < 0.05). HI titers against H1N1 (p < 0.01), H3N2 (p < 0.01), BV (p < 0.001) and BY (p < 0.01) significantly increased in the vaccinated group at 28 days post-vaccination. Moreover, a marked and sustained increase in HI titers against the H3N2 strain (p < 0.001) was observed at 180 days post-vaccination, highlighting the vaccine’s enduring impact on the immune response. The fold change in the HI titers, indicative of the magnitude of the immune response, was significantly higher for H1N1 (p < 0.01), H3N2 (p < 0.001), BV (p < 0.01) and BY (p < 0.05) among the vaccinated individuals compared to the control group, underscoring the vaccine’s efficacy in eliciting a robust and sustained antibody response. Conclusion: Influenza vaccination significantly reduces the incidence of influenza-like illness among healthcare workers and promotes a sustained immune response. The study supports the importance of annual vaccination for this group to enhance personal and public health.

Designs for Vaccine Studies

Due to dependent happenings, vaccines can have different effects in populations. In addition to direct protective effects in the vaccinated, vaccination in a population can have indirect effects in the unvaccinated individuals. Vaccination can also reduce person-to-person transmission to vaccinated individuals or from vaccinated individuals compared with unvaccinated individuals. Design of vaccine studies has a history extending back over a century. Emerging infectious diseases, such as the SARS-CoV-2 pandemic and the Ebola outbreak in West Africa, have stimulated new interest in vaccine studies. We focus on some recent developments, such as target trial emulation, test-negative design, and regression discontinuity design. Methods for evaluating durability of vaccine effects were developed in the context of both blinded and unblinded placebo crossover studies. The case-ascertained design is used to assess the transmission effects of vaccines. The novel ring vaccination trial design was first used in the Ebola outbreak in West Africa.

Development and characterization of high-throughput serological assays to measure magnitude and functional immune response against S. Paratyphi A in human samples.

Typhoid and Paratyphoid fever cause a global health burden, especially for the children of Southern Asia. The impact of the disease is further exacerbated by the dramatic increase of antimicrobial resistance. While vaccines against Salmonella Typhi have been developed and successfully introduced, an effective vaccine targeting S. Paratyphi A is still lacking. Several efforts are currently ongoing to develop vaccines targeting both S. Typhi and S. Paratyphi A. In order to analyze the immune response induced by vaccination and in sero-epidemiological studies, easy to perform and high throughput immunoassays are needed. Here we present the setup and characterization of a customized ELISA assay and of a luminescent-based serum bactericidal assay (L-SBA) to measure the quantity of S. Paratyphi O antigen specific antibodies and their functional activity against S. Paratyphi A. Robust quality control criteria have been put in place both for ELISA and SBA and assays have been fully characterized in terms of quantitation limit, limit of blanks, specificity, linearity and precision. Assays are being employed to analyze samples from clinical trials, enabling the assessment of immunogenicity during clinical vaccine development.

Detection of Hepatovirus A (HAV) in wastewater indicates widespread national distribution and association with socioeconomic indicators of vulnerability.

Wastewater-based epidemiology, which seeks to assess disease occurrence in communities through measurements of infectious disease biomarkers in wastewater, may represent a valuable tool for understanding the occurrence of hepatitis A infections in communities. In this study, we measured concentrations of Hepatovirus A (HAV) RNA, in samples from 191 wastewater treatment plants spanning 40 US states and the District of Columbia from September 2023 to June 2024 and compared the measurements with traditional measures of disease occurrence. Nationally, 13.76% of the 21,079 wastewater samples were positive for HAV RNA, and both concentrations and positivity rates were associated with NNDSS hepatitis A case data nationally (Kendall rank correlation coefficient = 0.20, concentrations; and 0.33, positivity rate; both P < 0.05). We further demonstrated that higher rates of wastewater HAV detection were positively associated with socioeconomic indicators of vulnerability including homelessness and drug overdose deaths (both P < 0.0001). Areas with above average levels of homelessness were 48% more likely to have HAV wastewater detections, while areas with above average levels of drug overdose deaths were 14% more likely to have HAV wastewater detections. Using more granular case data, we present a case study in the state of Maine that reinforces these results and suggests a potential lead time for wastewater over clinical case detection and exposure events. The ability to detect HAV RNA in wastewater before clinical cases emerge could allow public health officials to implement targeted interventions like vaccination campaigns.IMPORTANCEDespite the existence of a highly effective vaccine for hepatitis A, outbreaks in vulnerable populations remain common. The disease can be asymptomatic or subclinical, and disproportionately impacts populations with inadequate access to healthcare, leading to a severe underestimation of the occurrence of this viral infection. This study investigates the potential for wastewater measurements of biomarkers of the causative agent of hepatitis A (HAV RNA) to provide insights into disease occurrence. Results highlight the potential for wastewater-based epidemiology to be a complementary tool to traditional surveillance for monitoring and controlling HAV transmission.

Epidemiological and Genetic Insights of the Circulating Foot-and-Mouth Disease Virus Serotypes in Egypt

Foot-and-mouth disease virus (FMDV) remains a major threat to livestock in Egypt, with ongoing outbreaks involving serotypes A, O, and SAT2. This study aimed to improve the understanding of these circulating FMDV strains to improve control measures. Between 2022 and 2023, 134 cattle samples from across Egypt were analyzed, revealing a 67.9% positivity rate for Pan FMDV. Of these positive samples, 64 were identified as serotype A and 27 as serotype O. Genetic analysis indicated that serotype O strains clustered within the EA-3 topotype, suggesting endemic persistence and potential vaccine evasion, while serotype A strains were associated with the African topotype and linked to regions such as Ethiopia, Kenya, and Sudan. Notable amino acid mutations in the VP1 protein of both serotypes highlighted potential challenges to vaccine effectiveness. These findings underscore the need for enhanced surveillance, timely vaccine updates, and regional cooperation to effectively manage FMD outbreaks in Egypt and neighboring countries.

Evaluating the Quality of Studies Assessing COVID-19 Vaccine Neutralizing Antibody Immunogenicity

Objective: COVID-19 vaccine-neutralizing antibodies provide early data on potential vaccine effectiveness, but their usefulness depends on study reliability and reporting quality. Methods: We systematically evaluated 50 published post-vaccination neutralizing antibody studies for key parameters that determine study and data quality regarding sample size, SARS-CoV-2 infection, vaccination regimen, sample collection period, demographic characterization, clinical characterization, experimental protocol, live virus and pseudo-virus details, assay standardization, and data reporting. Each category was scored from very high to low or unclear quality, with the lowest score determining the overall study quality score. Results: None of the studies attained an overall high or very high score, 8% (n = 4) attained moderate, 42% (n = 21) low, and 50% (n = 25) unclear. The categories with the fewest studies assessed as ≥ high quality were SARS-CoV-2 infection (42%), sample size (30%), and assay standardization (14%). Overall quality was similar over time. No association between journal impact factor and quality score was found. Conclusions: We found that reporting in neutralization studies is widely incomplete, limiting their usefulness for downstream analyses.

Person-Centered Web-Based Mobile Health System (Symptoms) for Reporting Symptoms in COVID-19 Vaccinated Individuals: Observational Study of System, Users, and Symptoms.

The full spectrum of side effects from COVID-19 vaccinations and infections, including milder symptoms or health effects that do not lead to health care visits, remains unknown. Person-centered self-reporting of symptoms may offer a solution. Monitoring patient-reported outcomes over time will vary in importance for different patients. Individuals have unique needs and preferences, in terms of both communication methods and how the collected information is used to support care. This study aims to describe how Symptoms, a system for person-centered self-reporting of symptoms and health-related quality of life, was utilized in investigating COVID-19 vaccine side effects. We illustrate this by presenting data from the Symptoms system in newly vaccinated individuals from the RECOVAC (Register-based large-scale national population study to monitor COVID-19 vaccination effectiveness and safety) study. During the COVID-19 pandemic, newly vaccinated individuals were identified as the ideal population to query for milder symptoms related to COVID-19 vaccinations and infections. To this end, we used posters in observation areas at 150 vaccination sites across the Västra Götaland region of Sweden, inviting newly vaccinated individuals to use a novel digital system, Symptoms. In the Symptoms system, users can track their symptoms, functioning, and quality of life as often as they wish, using evidence-based patient-reported outcome measures and short numeric rating scales. These scales cover a prespecified list of symptoms based on common COVID-19 symptoms and previously reported vaccine side effects. Participants could also use numeric rating scales for self-defined symptoms if their symptom was not included on the prespecified list. A total of 731 people created user accounts and consented to share data for research between July 21, 2021, and September 27, 2022. The majority of users were female (444/731, 60.7%), with a median age of 38 (IQR 30-47) years. Most participants (498/702, 70.9%) did not report any of the comorbidities included in the questionnaire. Of the 731 participants, 563 (77.0%) reported experiencing 1 or more symptoms. The most common symptom was pain at the injection site (486/563, 86.3%), followed by fatigue (181/563, 32.1%) and headache (169/563, 30.0%). In total, 143 unique symptoms were reported. Of these, 29 were from the prespecified list, while the remaining 114 (79.7%) were self-defined entries in the symptom field. This suggests that the flexibility of the self-directed system-allowing individuals to decide which symptoms they consider worth tracking-may be an important feature. Self-reported symptoms in the Symptoms system appeared to align with previously observed post-COVID-19 vaccination symptoms. The system was relatively easy to use and successfully captured broad, longitudinal data. Its person-centered and self-directed design seemed crucial in capturing the full burden of symptoms experienced by users.

Cost-Effectiveness of Bivalent Respiratory Syncytial Virus Prefusion F Vaccine for Prevention of Respiratory Syncytial Virus Among Older Adults in Greece

Background/Objectives: To evaluate the health benefits, costs, and cost-effectiveness of vaccination with bivalent respiratory syncytial virus stabilized prefusion F vaccine (RSVpreF) for the prevention of lower respiratory tract disease caused by respiratory syncytial virus (RSV) in Greek adults 60 years of age and older. Methods: A Markov model was adapted to simulate lifetime risk of health and economic outcomes from the public payer’s perspective over a lifetime horizon. Epidemiology, vaccine effectiveness, utilities, and direct medical costs (EUR, 2024) were obtained from published studies, official sources, and local experts. Model outcomes included the number of medically attended RSV cases, stratified by care setting (i.e., hospital, emergency department [ED], outpatient visits [OV]), and attributable RSV-related deaths, costs, life years (LY), quality-adjusted life-years (QALY), and incremental cost-effectiveness ratios (ICERs) of RSVpreF vaccination compared with no vaccination. Results: The model projected 258,170 hospitalizations, 112,248 ED encounters, 1,201,604 OV, and 25,463 deaths related to RSV in Greek older adults resulting in direct medical costs of EUR 1.6 billion over the lifetime horizon. Assuming RSV vaccination would reach the same coverage rates as pneumococcal and influenza programmes, 18,118 hospitalizations, 7874 ED encounters, 48,079 OV, and 1706 deaths could be prevented over the modelled time horizon. The health benefits associated with RSVpreF contributed to an incremental gain of 10,976 LYs and 7230 QALYs compared with no vaccination. The incremental analysis reported that vaccination with RSVpreF was estimated to be a cost-effective strategy resulting in ICERs of EUR 12,991 per LY gained, EUR 19,723 per QALY gained, and EUR 7870 per hospitalized RSV case avoided compared with no vaccination. Conclusions: Vaccination with RSVpreF was a cost-effective strategy for the prevention of RSV disease in Greek adults over 60 years of age. The introduction of RSV vaccination can improve public health by averting RSV cases and deaths and has the potential to fulfil an unmet medical need.

Prospects of Carica papaya in the treatment of human viral infections: A comprehensive and a systematic review

BackgroundViruses cause various human diseases, some of which become pandemic outbreaks lack effective treatments and vaccines. This study gathered data on Carica papaya's antiviral effects against various human viruses, highlighting its potential as a natural treatment. Through in-vitro, in-vivo, and clinical study analysis, we illustrated the potential of Carica papaya in combating viral infections and its potential role in cure of common viral diseases. Methodology: Research papers on antiviral activity of Carica papaya were identified by using specific keywords in PUBMED, Google Scholar, and ScienceDirect databases. Articles published between January 2015 and March 2024 were screened for inclusion. Eligible studies utilized Carica papaya leaves (powder or juice) or fruits to investigate their effects against human viral infections. Each selected study applied either qualitative or quantitative antiviral assays to assess the efficacy of Carica papaya in combating human viruses. ResultsFifteen studies went through assessment for antiviral properties of Carica papaya, 7 (46.67 %) of them displayed significant activity against the dengue virus, while 1 study (6.67 %) demonstrated moderate/less effectiveness against dengue serotype-2. Two studies (13.33 %) found no anti-dengue effects. Additionally, Carica papaya exhibited strong antiviral activity against SARS-CoV-2 in 2 studies (13.33 %). One study (6.67 %) showed inhibition of both dengue serotype-2 and chikungunya, and 1 study (6.67 %) each demonstrated inhibitory effects against human immunodeficiency virus and Zika virus infections. ConclusionThe present study listed human diseases for which Carica papaya revealed significant antiviral effects against Dengue virus, Severe acute respiratory syndrome, Human immunodeficiency virus-I, Chikungunya virus and Zika virus suggesting its potential as a treatment candidate for all these viruses. However, the majority of the research involved in-vitro screening, with minimal in-vivo and clinical testing. Further in-vivo studies and clinical trials should be conducted to explore the potential of Carica papaya in the treatment of human viral infections.

Vaccination against COVID-19 in a geographically dispersed and underserved population, challenges and solutions in access and distribution of vaccines

Background As of July 2021, only 57% of Ecuador’s population had received the first vaccine dose against COVID-19. The national immunization campaign faced difficulties in reaching and providing vaccines to underserved population in remote areas. Methods The RISE project, funded by USAID and implemented by Jhpiego, aimed to develop an immunization strategy, that through the collaboration of an international non-profit organization, an academic institution and the public sector, could effectively support the national vaccination campaign of the Ecuadorian Ministry of Public Health. Results The program identified gaps in vaccination access and uptake, established specific strategies for targeted communities, analyzed official geographical information on vaccination coverage, ran micro-planning exercises at the local level, and adapted to new needs identified to ensure an effective vaccination uptake. From November 2021 up to May 2023, more than 1.8 million COVID-19 vaccine doses were administered to underserved populations living in geographically dispersed areas, in 18 provinces. Conclusions Employing data-targeted approaches and microplanning to identify underserved populations, strategic planning and collaboration between local governments, private sector, academic institution, and community leaders can substantially improve COVID-19 vaccines coverage and, thus, equity to vaccine access. The lessons learned might be useful to improve overall immunization service delivery.

Large Clostridial Toxins: A Brief Review and Insights into Antigen Design for Veterinary Vaccine Development.

The group of large clostridial toxins (LCTs) includes toxins A (TcdA) and B (TcdB) from Clostridioides difficile, hemorrhagic and lethal toxins from Paeniclostridium sordellii, alpha toxin from Clostridium novyi (TcnA), and cytotoxin from Clostridium perfringens. These toxins are associated with severe pathologies in livestock, including gas gangrene (P. sordellii and C. novyi), infectious necrotic hepatitis (C. novyi), avian necrotic enteritis (C. perfringens), and enterocolitis (C. difficile). Immunoprophylaxis is crucial for controlling these diseases, but traditional vaccines face production challenges, such as labor-intensive processes, and often exhibit low immunogenicity. This has led to increased interest in recombinant vaccines. While TcdA and TcdB are well-studied for human immunization, other LCTs remain poorly characterized and require further investigation. Therefore, this study emphasizes the importance of understanding lesser-explored toxins and proposes using immunoinformatics to identify their immunodominant regions. By mapping these regions using silico tools and considering their homology with TcdA and TcdB, the study aims to guide future research in veterinary vaccinology. It also explores alternatives to overcome the limitations of conventional and recombinant vaccines, offering guidelines for developing more effective vaccination strategies against severe infections in animals.

A Molecular Approach to Understand the Involvement of Mycoplasma in Suppurative Otitis Cases of Cattle in Chittoor District of Andhra Pradesh

In bovines the economic losses mainly due to the outbreak of diseases, leads to mortality, morbidity, treatment cost and reduced production. Recently in August month of 2024, received 13 bovine suppurativeotitis samples from outbreak in KuppamMandal of Chittoor district. The history having the purulent discharges with foul smell from ear infections of cattle that to crossbreed cattle of all age groups are affected. After 5 days of appearing aural discharges the animals were also shown the nervous signs, head tilting and other clinical findings includes unilateral or bilateral ear droop, epiphora, ptosis, abnormal nystagmus, strabismus, regurgitation, stiff neck, opisthotonus, facial hyperesthesia, purulent aural discharge, nasopharyngeal collapse, recumbency and finally death were noticed in severely affected animals. All the samples were processed for cultural tests by inoculating in PPLO selective broth and selective media PPLO agar then incubated anaerobically at 370C and observed the color development in broth pink to yellow color after 3- 5 days of incubation indicative of positive growth and fried egg micro colonies on selective PPLO agar media after 8-14 days of incubation observed under low power and 40X. The DNA was isolated from all the samples and screened for presence of Mycoplasma by targeting 16s rRNA gene and found that out of 13 samples 10 were positive for genus Mycoplasma and produced the predicted 280bp size product in all positive samples. The suppurativeotitis in cattle usually is caused by Actinomyces spp., Corynebacterium pseudotuberculosis, E. coli, Heamophilus, P.multocida, Pseudomonas spp, Streptococcus spp., and Mycoplasma bovis. This study was targeted only the emerging pathogen i.e the cellwall deficient bacteria Mycoplasma because of infections is hampered by a lack of effective vaccines and specific treatments, leads to increasing trends in antimicrobial resistance. Concluded that isolation and identification of the pathogenic ........

Fractional-Order Modeling of COVID-19 Transmission Dynamics: A Study on Vaccine Immunization Failure

COVID-19 is an enveloped virus with a single-stranded RNA genome. The surface of the virus contains spike proteins, which enable the virus to attach to host cells and enter the interior of the cells. After entering the cell, the virus exploits the host cell’s mechanisms for replication and dissemination. Since the end of 2019, COVID-19 has spread rapidly around the world, leading to a large-scale epidemic. In response to the COVID-19 pandemic, the global scientific community quickly launched vaccine research and development. Vaccination is regarded as a crucial strategy for controlling viral transmission and mitigating severe cases. In this paper, we propose a novel mathematical model for COVID-19 infection incorporating vaccine-induced immunization failure. As a cornerstone of infectious disease prevention measures, vaccination stands as the most effective and efficient strategy for curtailing disease transmission. Nevertheless, even with vaccination, the occurrence of vaccine immunization failure is not uncommon. This necessitates a comprehensive understanding and consideration of vaccine effectiveness in epidemiological models and public health strategies. In this paper, the basic regeneration number is calculated by the next generation matrix method, and the local and global asymptotic stability of disease-free equilibrium point and endemic equilibrium point are proven by methods such as the Routh–Hurwitz criterion and Lyapunov functions. Additionally, we conduct fractional-order numerical simulations to verify that order 0.86 provides the best fit with COVID-19 data. This study sheds light on the roles of immunization failure and fractional-order control.

Vaccination status and long COVID symptoms among patients hospitalized with COVID-19: the WHF COVID-19 Long-term Study

Abstract Background COVID-19 vaccinations have been found to be effective in reducing the severity of COVID-19 infection and in-hospital deaths; however, insufficient evidence exists about the effect of vaccination on long term morbidity and mortality after hospitalization in patients from low- and middle-income countries. Methods The global WHF COVID-19 Long-Term Follow-up Study recruited 2,504 COVID-19 hospitalized patients from 26 collaborating sites in 16 countries between January 2022 - June 2023. Patients were followed up , at 1, 3, 6, and 9-12 months post-discharge to examine short- and long-term physical and psycho-social outcomes. A standardised questionnaire was used to collect data on demographics, pre-existing comorbidities, COVID-19 symptoms on admission, vaccination status, and outcomes at discharge, including persisting symptoms, new onset hypertension or diabetes, major adverse cardiovascular events (MACE), and mortality. We compared persistent long COVID symptoms, MACE, and mortality outcomes up to one year by COVID-19 vaccination status. Results The majority of study participants were Asians (78%), males (56%) with a mean (SD) age of 59.2 (19.9) years and from low- and middle-income (65%), upper middle-income (20%) and high-income (15%) countries. The most commonly reported comorbidities were hypertension: 54% and diabetes: 38%. Approximately two-thirds of the patients had received at least one dose of COVID-19 vaccination prior to hospitalization. Unvaccinated patients were more likely to present with dyspnea (60% vs 53%, p-value&amp;lt;0.001) and acute respiratory infection (15% vs 9%, p-value&amp;lt;0.001) during hospitalization. Unvaccinated patients also had twice the in-hospital mortality rate, compared with vaccinated patients (6% vs 3%, p-value&amp;lt;0.001). Unvaccinated patients had a greater incidence of MACE (23% vs 18%, p-value=0.016) during hospitalization and across all follow-up visits. Unvaccinated patients also had a higher mortality rate across all follow-up visits (mortality at one year post-discharge 14% vs 10%, p&amp;lt;0.001). At the 9-12 month follow-up, about a quarter of the patients had at least one long COVID symptom, but unvaccinated patients had a higher rate of long COVID symptoms, including fatigue (23% vs 14%, p&amp;lt;0.001), palpitations (17% to 7%, p-value&amp;lt;0.001), and anxiety (13% to 7%, p=0.002). Conclusions Our data highlight the long-term protective effect of COVID-19 vaccination on reducing morbidity and mortality among COVID-19 patients after hospital discharge. However, a substantial proportion of COVID-19 vaccinated patients still showed persistent long COVID symptoms (22%) and mortality (10%). Future research is needed to investigate individual- and health system-level factors contributing to poor health outcomes post-COVID-19 infection.

One-pot synthesis of chiral cysteine-capped gold nanoparticles for use as vaccine adjuvants in mice

The influence of chirality on the biological activity of nanoparticles, including their interaction with the immune system, is a growing area of interest. This study presents a one-pot synthesis method for 15 nm L-cysteine or D-cysteine capped gold nanoparticles (L/D-Cys-GNPs) and evaluates their immunological potential as adjuvants in mice. The synthesized GNPs were comprehensively characterized using UV–visible absorption spectroscopy, FTIR, CD spectra, and TEM, revealing enhanced stability and effective internalization by human umbilical vein endothelial cells (HUVEC), with L-Cys-GNPs exhibiting a higher uptake rate. In vivo immunization studies demonstrated that L-Cys-GNPs significantly boosted the production of anti-ovalbumin(OVA) IgG antibodies compared to D-Cys-GNPs (>66 folds), underscoring the importance of chiral surface properties in modulating immune responses. However, the encapsulation of GNPs in liposomes negated the chiral effect, suggesting that delivery methods may influence the interaction of GNPs with the immune system. The findings highlight the role of chirality in vaccine development and provide insights into targeted antigen delivery systems. This work contributes to the understanding of chirality in vaccine development and paves the way for the design of more effective vaccines against challenging diseases.

Roles of helminth extracellular vesicle-derived let-7 in host-parasite crosstalk.

Helminth infections are a major public health problem as they can cause long-term chronic infections in their hosts for which there is no effective vaccine. During the long-term interaction between helminths and their hosts, helminth-derived extracellular vesicles (EVs) can participate in host immunomodulatory processes by secreting bioactive molecules (BMAs). Growing data suggests that microRNAs (miRNAs) in helminth EVs have a significant impact on the host's immune system. The let-7 family is highly conserved among helminth EVs and highly homologous in the host, and its function in host-parasite crosstalk may reflect active selection for compatibility with the host miRNA machinery. In-depth studies targeting this aspect may better elucidate the mechanism of parasite-host interactions. Hence, this review summarizes the current studies on the cross-species involvement of helminth EV-derived let-7 in host immune regulation and discusses the barriers to related research and potential applications of helminth EVs.

Influenza vaccine effectiveness in Ireland during two influenza seasons, 2022/23 and 2023/24

Abstract Background Live Attenuated Influenza Vaccine (LAIV) is recommended in Ireland for all children aged 2-17 years. Quadrivalent influenza vaccine is recommended for all others eligible for vaccination, including those aged ≥18 years with underlying medical conditions and all aged ≥65 years. We aimed to estimate influenza vaccine effectiveness (IVE) against Acute Respiratory Infection (ARI) presentations to primary care due to influenza over two influenza seasons in Ireland, to inform vaccination recommendations and communication campaigns. Methods We undertook a test-negative design case control study within the national sentinel surveillance General Practice network, as part of the European Vaccine Effectiveness Burden and Impact Studies (VEBIS) network. We compared influenza vaccination status among influenza Polymerase Chain Reaction (PCR) positive cases with influenza PCR negative controls, amongst patients consulting with ARI. We verified vaccination status using the national influenza vaccination database. We estimated end of season IVE for 2022/23, and mid-season IVE (up to 7th April 2024) for 2023/24, using multivariable logistic regression and adjusting for age, onset time, medical condition, and sex. Results In 2022/23, there were 288 cases and 765 controls. In 2023/24 there were 515 cases and 1,482 controls. Overall vaccination coverage was 23% in both seasons. Coverage in 2-17 year-olds was 10% in 2022/23 and 12% in 2023/24. In 2022/23, overall IVE was 42% (95%CI 9-54) and 50% (95%CI -30-83) in 2-17 year-olds. Overall IVE in 2023/24 was 37% (95%CI 16-54) and was 67% (95%CI 28-87) in 2-17 year-olds. Conclusions Influenza vaccination reduced medical attendance to primary care with ARI due to influenza, demonstrating benefits of vaccination, particularly among children. Influenza vaccination should continue to be offered and promoted to recommended groups, including children. Key messages • This study suggests that influenza vaccination protected population health and the health service from medical attendance to primary care with acute respiratory infection due to influenza. • Higher influenza vaccine effectiveness was observed in children aged 2-17 years. These findings can inform influenza vaccination programmes with LAIV for children in Ireland and internationally.

Estimated number of COVID-19 deaths averted by vaccination in Belgium

Abstract Background Vaccination campaigns have been rolled out globally to limit the impact of COVID-19 on severe health outcomes, including mortality. We aimed to estimate the number of averted deaths by COVID-19 vaccination in the Belgian population aged ≥65 years, between January 2021 and January 2023. Methods Nationwide data on COVID-19 infections, vaccinations and all-cause mortality were individually linked. We estimated Vaccine Effectiveness against COVID-19 mortality (VE) in persons having received a vaccine dose in the last 6 months using a Cox proportional hazards model adjusted for age, sex, time since vaccination, previous infection, comorbidities, province and income. COVID-19 death was defined as a death within 1-7 weeks after a positive SARS-CoV-2 laboratory-test. Based on obtained VE estimates, vaccine coverage and national COVID-19 mortality data, we estimated the number of averted deaths (expected deaths without vaccinating minus the reported deaths). Results By January 31st 2023, 11,033 COVID-19 deaths have been reported in Belgium. The average vaccine coverage was 48% during alpha, 85% during delta and 63% during omicron dominance. VE was estimated at 0-59 days after vaccination, for 65-79 year and ≥80 year-olds respectively, at 65% (58%-60%) and 35% (28%-41%) during Alpha, at 84% (82%-87%) and 79% (77%-81%) during Delta and at 83% (80%-85%) and 71% (68%-73%) during Omicron dominance. We estimated 10,042 deaths averted (range: 8,917-11,188) among the Belgian population aged ≥65 years, representing a 48% reduction (range 45%-50%) in the expected deaths. Out of 10,042 averted deaths, the majority was averted during Delta (47%; 4,670) or Omicron dominance (43%; 4,366), compared to during Alpha dominance (10%; 1,006). Conclusions Vaccinating against COVID-19 led to an important reduction in COVID-19-related mortality among the Belgian population ≥65 years, in particular during Delta and Omicron dominance, underscoring the effectiveness of vaccines against mortality. Key messages • Vaccinating against COVID-19 led to an important reduction of 48% in COVID-19-related mortality among the Belgian population ≥65 years, in particular during Delta and Omicron dominance. • Vaccine effectiveness against COVID-19 mortality was estimated as high in the Belgian population ≥65 years (range: 71-84%) during Delta and Omicron dominance, also among elderly over 80 years.

Estimating the impact of the COVID-19 vaccination programme in Ireland: December 2021-March 2023

Abstract Background In Autumn 2023, COVID-19 booster vaccines were offered to all those aged ≥50 years in Ireland. There was concern that vaccine fatigue would impact uptake. We aimed to quantify the direct impact of the COVID-19 vaccination programme on averted outcomes in individuals aged ≥50 years, during a period of Omicron variant dominance, to inform vaccination strategy and public health communication. Methods We conducted a retrospective observational study from December 2021 to March 2023 in Ireland. We considered as averted outcomes symptomatic SARS-CoV-2 presentations to primary care, emergency department (ED) presentations, hospitalisations, intensive care unit (ICU) admissions and deaths due to COVID-19. We used an adapted formula from other vaccine impact published studies, including national data on notified outcomes, vaccine coverage data and vaccine effectiveness (VE) estimates, sourced from the WHO’s live systematic VE review, to estimate the count and prevented fraction of outcomes in ≥ 50-year-olds averted by the COVID-19 vaccination programme. The number of expected outcomes in the absence of vaccination was calculated by summing the counts of outcomes observed and outcomes averted. Results Between December 2021 and March 2023, the COVID-19 vaccination programme averted 48,551 symptomatic presentations to primary care (36% of expected), 9,517 ED presentations (53% of expected), 102,160 hospitalisations (81% of expected), 3,303 ICU admissions (89% of expected) and 15,985 deaths (87% of expected). Conclusions During Omicron dominance, the COVID-19 vaccination programme averted symptomatic and severe outcomes, including deaths due to COVID-19, underscoring the benefits of COVID-19 vaccination. In the context of vaccine fatigue emerging as an important public health issue in Ireland and internationally, these findings can inform future COVID-19 booster vaccination programmes and communication about the reason for and importance of COVID-19 vaccination. Key messages • The COVID-19 vaccination programme in Ireland prevented illness and death in people aged ≥50-years. Vaccination therefore protected population health and the healthcare system. • These findings can be used to inform future COVID-19 vaccination policies, planning for winter, pandemic preparedness and communisation about the importance of ongoing COVID-19 vaccination programmes.