Vaccines, Volume 12, Issue 3 (March 2024) – 124 articles

This study aimed to understand Poles’ attitudes and beliefs towards influenza vaccinations in the flu season of 2022–2023, especially among individuals at risk of flu complications. The cross-sectional survey-based study was carried out on a sample of 810 respondents. The questionnaire was disseminated electronically using social media and e-mail. The majority of respondents (71%) could identify “high-risk groups” recommended for influenza vaccination, and 52.01% of respondents reported receiving influenza vaccination at some point in the past, with 32.12% receiving it in the 2022–2023 flu season and 41.09% in the 2021–2022 season. The majority of respondents declaring acceptance of the vaccine for the 2022–2023 season were in the high-risk group. Only 17.28% of respondents declared receiving both influenza and SARS-CoV-2 vaccines in the 2022–2023 season, with the vast majority being respondents from the “high-risk group” (p < 0.0001). Only 26.12% of respondents declared their intention to continue influenza vaccination in the future. Of those expressing the intention to get vaccinated against the influenza virus in future seasons, 46.79% were from the “high-risk group” (p = 0.0087). Results suggest the need for further interaction and education with healthcare providers and targeted informational efforts for at-risk groups regarding the benefits of flu vaccination. Full article

Natural 4-1BBL (CD137L) is a cell membrane-bound protein critical to the expansion, effector function, and survival of CD8⁺ T cells. We reported the generation of an active soluble oligomeric construct, SA-4-1BBL, with demonstrated immunoprevention and immunotherapeutic efficacy in various mouse tumor models. Herein, we developed an oncolytic adenovirus (OAd) for the delivery and expression of SA-4-1BBL (OAdSA-4-1BBL) into solid tumors for immunotherapy. SA-4-1BBL protein expressed by this construct produced T-cell proliferation in vitro. OAdSA-4-1BBL decreased cell viability in two mouse lung cancer cell lines, TC-1 and CMT64, but not in the non-cancerous lung MM14.Lu cell line. OAdSA-4-1BBL induced programmed cell death types I and II (apoptosis and autophagy, respectively), and autophagy-mediated adenosine triphosphate (ATP) release was also detected. Intratumoral injection of OAdSA-4-1BBL efficiently expressed the SA-4-1BBL protein in the tumors, resulting in significant tumor suppression in a syngeneic subcutaneous TC-1 mouse lung cancer model. Tumor suppression was associated with a higher frequency of dendritic cells and an increased infiltration of cytotoxic CD8⁺ T and NK cells into the tumors. Our data suggest that OAdSA-4-1BBL may present an efficacious alternative therapeutic strategy against lung cancer as a standalone construct or in combination with other immunotherapeutic modalities, such as immune checkpoint inhibitors. Full article

The COVID-19 outbreak was a global pandemic with wide-ranging healthcare implications. Although several mRNA-based vaccines delivered using lipid nanoparticles (LNP) have been approved and demonstrated efficacy at reducing the severity and spread of infection, continued rapid viral evolution and disadvantages currently associated with LNP delivery vehicles (such as toxicity) are driving the design of next-generation SARS-CoV-2 vaccines. Herein, we describe the development of a trimethylated chitosan-based nanoparticle layer-by-layer (LbL) delivery platform for multiple antigens as a scalable and safe COVID-19 vaccine, known as, “LbL-CoV19”. These vaccine candidates have been demonstrated to be biocompatible, safe, and effective at stimulating both humoral and cellular responses for protection in preclinical studies. Preliminary results also indicate that LbL-CoV19 can potentially achieve rapid, long-lasting, and broad protection against the SARS-CoV-2 challenge. The “plug-and-play” platform technology is well suited to preparedness for future pandemics and disease outbreaks. Full article

To ensure that limited domestic resources are invested in the most effective interventions, immunization programs in low- and middle-income countries (LMICs) must prioritize a growing number of new vaccines while considering opportunities to optimize the vaccine portfolio, as well as other components of the health system. There is a strong impetus for immunization decision-making to engage and coordinate various stakeholders across the health system in prioritization. To address this, national immunization program decision-makers in LMICs collaborated with WHO to structure deliberation among stakeholders and document an evidence-based, context-specific, and transparent process for prioritization or selection among multiple vaccination products, services, or strategies. The output of this effort is the Country-led Assessment for Prioritization on Immunization (CAPACITI) decision-support tool, which supports using multiple criteria and stakeholder perspectives to evaluate trade-offs affecting health interventions, taking into account variable data quality. Here, we describe the user feedback from Indonesia and Ethiopia, two initial countries that piloted the CAPACITI decision-support tool, highlighting enabling and constraining factors. Potential immunization program benefits and lessons learned are also summarized for consideration in other settings. Full article

Background: This cross-sectional survey investigated the knowledge, attitudes, and coverage of recommended vaccinations among a random sample of patients with chronic medical conditions, at higher risk of vaccine-preventable diseases (VPDs), in Italy. Methods: The survey was conducted via telephone-based interviews. Results: Multinomial regression analysis showed that the patients who believed that VPDs were severe were more likely to know one recommended vaccination; those who believed that VPDs were severe and those who were advised from a general practitioner (GP) were more likely to know two vaccinations; those who were older, graduated, with more time from diagnosis, who believed that VPDs were severe, who did not need additional information, and who were advised from a GP were more likely to know three or four vaccinations. Patients who knew at least one vaccination, who perceived themselves at risk, and who were advised from a GP were more likely to have received one vaccination; those who knew more than one vaccination and who were advised from a GP were more likely to receive two or three vaccinations. Among the unvaccinated, patients who were unmarried/not cohabiting, those who needed information, and who believed that vaccinations were useful and safe were more willing to receive the recommended vaccinations. Conclusions: Educational interventions are needed to improve the adherence of individuals with chronic medical conditions. Full article

Background: Despite the efforts of the World Health Organization, some childhood viral diseases, for which there is already an effective vaccine, have not yet been eradicated. Among these, we find varicella, mumps, measles, and rubella, which although in most cases have a benign course, can in some cases be responsible for infectious outbreaks, especially in nosocomial settings. The aim of this study was to verify the immunological situation of a cohort of trainee obstetricians in Campania regarding varicella, mumps, measles, and rubella to be used as an example for the evaluation of possible preventive strategies to avoid infectious outbreaks. Methods: All the samples collected and sent to the laboratory were eligible for analysis and have been included in the study. Specific IgG for varicella, measles, mumps, and rubella were assayed on serum samples taken from 517 trainee obstetricians using the enzyme-linked immunosorbent assay (ELISA) technique. The seropositivity results were statistically analyzed by correlating them to age group and gender. Results: The results obtained show that a percentage of trainee obstetricians tested do not have an effective immunological coverage against at least one of the vaccine-preventable diseases considered, especially for mumps. Conclusions: Therefore, it is proposed to extend surveillance to other professionals in contact with frail patients and increase awareness of vaccination campaigns. Full article

Varicella-zoster virus (VZV) poses lifelong risks, causing varicella and herpes zoster (HZ, shingles). Currently, varicella and HZ vaccines are predominantly live attenuated vaccines or adjuvanted subunit vaccines utilizing VZV glycoprotein E (gE). Here, we propose our vaccine candidates involving a comparative analysis between recombinant baculoviral vector vaccines (AcHERV) and a live attenuated vaccine strain, vOka. AcHERV vaccine candidates were categorized into groups encoding gE only, VZV glycoprotein B (gB) only, or both gE and gB (gE-gB) as AcHERV-gE, AcHERV-gB, and AcHERV-gE-gB, respectively. Humoral immune responses were evaluated by analyzing total IgG, IgG1, IgG2a, and neutralizing antibodies. Cell-mediated immunity (CMI) responses were evaluated by enzyme-linked immunospot (ELISPOT) assay and Th1/Th2/Th17 cytokine profiling. In the mouse model, AcHERV-gE-gB elicited similar or higher total IgG, IgG2a, and neutralizing antibody levels than vOka and showed robust VZV-specific CMI responses. From the perspective of antigens encoded in vaccines and their relationship with CMI response, both AcHERV-gB and AcHERV-gE-gB demonstrated results equal to or superior to AcHERV-gE, encoding only gE. Taken together, these results suggest that AcHERV-gE-gB can be a novel candidate for alleviating risks of live attenuated vaccine-induced latency and effectively preventing varicella during early stages of life while providing strong CMI for effective resistance against HZ and therapeutic potential in later stages of life. Full article

An mpox outbreak occurred suddenly and rapidly spread worldwide in 2022. Research has demonstrated a link between the sexual behavior of men who have sex with men (MSM) and the contraction of mpox. This study assessed the factors related to mpox-vaccine uptake among MSM in Taiwan, focusing on the roles of information sources and emotional problems. In total, 389 MSM participated in an online survey. Data on the participants’ vaccination statuses; anxiety symptoms, which were assessed using the State–Trait Anxiety Inventory; depressive symptoms, which were assessed using the Center for Epidemiologic Studies Depression Scale; and risk perceptions of contracting mpox were collected. Factors related to mpox-vaccine uptake were examined using a multivariable logistic regression model. The results revealed that MSM who were older (p < 0.001), perceived a higher risk of contracting mpox (p = 0.040), and received mpox information from health-care providers (p < 0.001) were more likely to receive mpox vaccination, whereas MSM who reported a greater severity of depression (p = 0.017) were less likely to receive mpox vaccination. However, age did not moderate the associations of perceiving a higher risk of contracting mpox, receiving mpox information from health-care providers, and depression with having an mpox vaccination. Health-care providers should consider these factors when developing intervention programs for enhancing mpox-vaccine uptake among MSM. Full article

Vaccine hesitancy has been included among the top ten threats to global health by the World Health Organization. Pharmacists can play a pivotal role in removing the individual barrier to vaccination, because of the relationship of trust they have with citizens and their ease of access. The aim of this study was to examine the impact of a pharmacy-based intervention to support the 2019 influenza vaccination campaign conducted in the Carnia district through one-to-one counseling. We analyzed data collected by pharmacists between 22 October 2019 and 20 January 2020, and trends in vaccination adherence in the context of the Local Health Authority and the entire province of Udine since 2016. The results showed that 77.2% of people who had not received an influenza vaccination in the previous year changed their minds about vaccination after receiving counseling. The pharmacy-based intervention improved influenza vaccination adherence in the target district (+13.4%), even when compared to the neighboring district of Gemona or considering the data in the broader local and provincial context, and this effect was particularly pronounced among those aged 65 to 74 years (p < 0.01). Considering these findings, pharmacies should be more effectively involved in the provision of public health services aimed at improving accessibility, timeliness, and equity. Full article

Coronaviruses (CoVs) are a large class of positively stranded RNA viruses that pose a significant threat to public health, livestock farming, and wild animals. These viruses have the ability to cross species barriers and cause devastating epidemics. Animals are considered to be intermediate hosts for many coronaviruses, and many animal coronaviruses also have the potential for cross-species transmission to humans. Therefore, controlling the epidemic transmission of animal coronaviruses is of great importance to human health. Vaccination programs have proven to be effective in controlling coronaviruses infections, offering a cost-effective approach to reducing morbidity and mortality, so the re-emergence of lethal coronaviruses emphasizes the urgent need for the development of effective vaccines. In this regard, we explore the progress in animal coronavirus vaccine development, covering the latest taxonomy of the main animal coronaviruses, spillover events, diverse vaccine development platforms, potential main targets for animal coronavirus vaccine development, and primary challenges facing animal coronavirus vaccines. We emphasize the urgent need to create a “dual-effect” vaccine capable of eliciting both cellular and humoral immune responses. The goal is to highlight the contributions of veterinary scientists in this field and emphasize the importance of interdisciplinary collaboration between the veterinary and medical communities. By promoting communication and cooperation, we can enhance the development of novel and super vaccines to combat human and animal coronavirus infections in the future. Full article

(1) Background: Some individuals are more susceptible to developing respiratory tract infections (RTIs) or coronavirus disease (COVID-19) than others. The aim of this work was to identify risk factors for symptomatic RTIs including COVID-19 and symptomatic COVID-19 during the coronavirus pandemic by using infection incidence, participant baseline, and regional COVID-19 burden data. (2) Methods: Data from a prospective study of 1000 frontline healthcare workers randomized to Bacillus Calmette–Guérin vaccination or placebo, and followed for one year, was analyzed. Parametric time-to-event analysis was performed to identify the risk factors associated with (a) non-specific symptomatic respiratory tract infections including COVID-19 (RTIs+COVID-19) and (b) symptomatic RTIs confirmed as COVID-19 using a polymerase chain reaction or antigen test (COVID-19). (3) Results: Job description of doctor or nurse (median hazard ratio [HR] 1.541 and 95% confidence interval [CI] 1.299–1.822), the reported COVID-19 burden (median HR 1.361 and 95% CI 1.260–1.469 for 1.4 COVID-19 cases per 10,000 capita), or a BMI > 30 kg/m² (median HR 1.238 and 95% CI 1.132–1.336 for BMI of 35.4 kg/m²) increased the probability of RTIs+COVID-19, while positive SARS-CoV-2 serology at enrollment (median HR 0.583 and 95% CI 0.449–0.764) had the opposite effect. The reported COVID-19 burden (median HR 2.372 and 95% CI 2.116–2.662 for 1.4 COVID-19 cases per 10,000 capita) and a job description of doctor or nurse (median HR 1.679 and 95% CI 1.253–2.256) increased the probability of developing COVID-19, while smoking (median HR 0.428 and 95% CI 0.284–0.648) and positive SARS-CoV-2 serology at enrollment (median HR 0.076 and 95% CI 0.026–0.212) decreased it. (4) Conclusions: Nurses and doctors with obesity had the highest probability of developing RTIs including COVID-19. Non-smoking nurses and doctors had the highest probability of developing COVID-19 specifically. The reported COVID-19 burden increased the event probability, while positive SARS-CoV-2 IgG serology at enrollment decreased the probability of RTIs including COVID-19, and COVID-19 specifically. Full article

(1) Background: Measles remains a major cause of disease and death worldwide, especially in the World Health Organization African Region. This study aimed to estimate the coverage of measles vaccinations and map the spatial distribution of measles vaccination dropout in Ethiopia; (2) Methods: A cross-sectional survey was conducted in Ethiopia’s underprivileged areas. The study included 3646 mothers/caregivers of children. ArcGIS for the spatial analysis, Global Moran’s I statistic for spatial autocorrelation, and Getis-Ord Gi* statistics for hot spot analysis were applied; (3) Results: Overall, coverages of measles-containing-vaccine first- and second-doses were 67% and 35%, respectively. Developing regions had the lowest coverages of measles-containing-vaccine first- and second-doses, 46.4% and 21.2%, respectively. On average, the measles vaccination dropout estimate was 48.3%. Refugees had the highest measles vaccination dropout estimate (56.4%). The hot spot analysis detected the highest burden of measles vaccination dropout mainly in the northeastern parts of Ethiopia, such as the Afar Region’s zones 1 and 5, the Amhara Region’s North Gondar Zone, and peripheral areas in the Benishangul Gumuz Region’s Assosa Zone; (4) Conclusions: The overall measles vaccination coverages were relatively low, and measles vaccination dropout estimates were high. Measles vaccination dropout hot spot areas were detected in the northeastern parts of Ethiopia. Full article

Purpose: To determine the impact of booster COVID-19 vaccination on SARS-CoV-2 symptoms. Background: The Omicron surge of infections provided an opportunity to evaluate symptoms in relation to booster receipt. Methods: At a US medical college, the number, type, and duration of symptoms were evaluated for 476 students or employees, factoring in days between last vaccination and SARS-CoV-2 diagnosis. Results: Compared with vaccinated non-boosted individuals, boosted individuals reported a significantly higher frequency of nasal congestion (57.9% vs. 44.4%, p = 0.018) and nasal congestion and/or sore throat (77.2% vs. 62.0%, p = 0.003); in contrast, the frequency of body/muscle aches was significantly less among boosted individuals (22.1% vs. 32.4%, p = 0.038). With each one week increase in time since booster receipt, the probability of fever increased significantly by 4.4% (OR 1.044, 95% CI 1.01, 1.07, p = 0.001), and the probability of cough increased significantly by 4.8% (OR 1.048, 95% CI 1.01, 10.8, p= 0.010). Conclusions: Within a medical college population, during the first 7 months of the Omicron surge of infections, compared with vaccinated non-boosted individuals, boosted individuals significantly more often reported the following: nasal congestion as well as nasal congestion and/or sore throat. In contrast, body/muscle aches were reported significantly less often. The rates of fever and cough each significantly increased as time since booster dose receipt increased. These data suggest that having had a booster vaccination, as well the timing of receiving it, impacts the clinical manifestations of breakthrough SARS-CoV-2 infections. Additional studies are needed to precisely define SARS-CoV-2 symptoms in relation to booster vaccinations. Full article

Few data are available on antibody response for some SARS-CoV-2 vaccines, and there is a lack of ability to compare vaccine responses in the same population. This cross-sectional study conducted in Nicaragua examines the SARS-CoV-2 antibody responses in individuals, previously exposed to high infection rates who have received various vaccines. The vaccines under comparison include well-known ones like Pfizer (BNT162b2) and AstraZeneca (ChAdOx1-S), alongside less-studied vaccines including Soberana (Soberana 02), Abdala (CIGB-66), and Sputnik V/Sputnik Light. Overall, 3195 individuals participated, with 2862 vaccinated and 333 unvaccinated. We found that 95% of the unvaccinated were seropositive, with much lower titers than the vaccinated. Among the vaccinated, we found that Soberana recipients mounted the highest anti-spike response (mean difference (MD) = 36,498.8 [20,312.2, 52,685.5]), followed by Abdala (MD = 25,889.9 [10,884.1, 40,895.7]), BNT162b2 (MD = 12,967.2 [7543.7, 18,390.8]) and Sputnik with AstraZeneca as the reference group, adjusting for age, sex, vaccine status, days after last dose, and self-reported COVID-19. In addition, we found that subjects with complete vaccination series had higher antibody magnitude than those with incomplete series. Overall, we found no evidence of waning in the antibody magnitude across vaccines. Our study supports the conclusion that populations with high infection rates still benefit substantially from vaccination. Full article

Quality control testing of vaccines, including potency assessment, is critical to ensure equivalence of clinical lots. We developed a potency assay to support the clinical advancement of Nous-209, a cancer vaccine based on heterologous prime/boost administration of two multivalent viral vector products: GAd-209 and MVA-209. These consist of a mix of four Adeno (Great Ape Adenovirus; GAd) and four Modified Vaccinia Ankara (MVA) vectors respectively, each containing a different transgene encoding a synthetic polypeptide composed of antigenic peptide fragments joined one after the other. The potency assay employs quantitative Reverse Transcription PCR (RT-Q-PCR) to quantitatively measure the transcripts from the four transgenes encoded by each product in in vitro infected cells, enabling simultaneous detection. Results showcase the assay’s robustness and biological relevance, as it effectively detects potency loss in one component of the mixture comparably to in vivo immunogenicity testing. This report details the assay’s setup and validation, offering valuable insights for the clinical development of similar genetic vaccines, particularly those encoding synthetic polypeptides. Full article

Porcine circovirus type 2 (PCV2) is the main causative agent of porcine circovirus-associated disease (PCVAD) that profoundly impacts the swine industry worldwide. While most of the commercial PCV vaccines are developed based on PCV genotype 2a (PCV2a), PCV genotype 2b (PCV2b) has become predominant since 2003. In this study, we developed and evaluated DNA-based bivalent vaccines covering both PCV2a and PCV2b. We generated a new immunogen, PCV2b-2a, by combining consensus sequences of the PCV2a and PCV2b capsid proteins (Cap2a and Cap2b) in a form of fusion protein. We also examined whether modifications of the PCV2b-2a fusion protein with a signal sequence (SS) and granulocyte macrophage-colony stimulating factor (GM-CSF) fusing with interleukine-4 (IL-4) (GI) could further improve the vaccine immunogenicity. An immunogenicity study of BALB/cAJcl mice revealed that the DNA vector pVAX1 co-expressing PCV2b-2a and GI (pVAX1.PCV2b-2a-GI) was most potent at inducing both antibody and cellular immune responses against Cap2a and Cap2b. Interestingly, the vaccines skewed the immune response towards Th1 phenotype (IgG2a > IgG1). By performing ELISA and ELISpot with predicted epitope peptides, the three most immunogenic B cell epitopes and five putative T cell epitopes were identified on Cap2a and Cap2b. Importantly, our DNA vaccines elicited broad immune responses recognizing both genotype-specific and PCV2-conserved epitopes. Sera from mice immunized with the DNAs expressing PCV2b-2a and PCV2b-2a-GI significantly inhibited PCV2a cell entry at serum dilution 1:8. All these results suggest a great potential of our PCV2b-2a-based vaccines, which can be further developed for use in other vaccine platforms to achieve both vaccine efficacy and economical production cost. Full article

African American men who have sex with men (MSM) are disproportionately impacted by HIV and may benefit from the development of an HIV vaccine. African American MSM are adversely affected by discrimination as a function of both their race and sexual behaviors. This may further increase the challenges associated with persuading them to adopt an HIV vaccine. Developing a knowledge base characterizing African American MSM HIV vaccine perceptions, attitudes, and concerns may help strengthen how healthcare providers and other health stakeholders describe and discuss the advent of an HIV vaccine. This study assessed the knowledge, attitudes, beliefs, and intentions related to HIV vaccination among African American MSM. This study comprised 432 African American MSM, 18–64 years, residing in the United States. Vaccine intention was defined as how likely it is that an individual would adopt an HIV vaccine if a vaccine was available and it was 90% effective against HIV, easy to obtain, free, and had few side effects. Relative to African American MSM who intend to delay receiving an HIV vaccination, controlling for age, education, and income, early vaccine adopters who had received ≥ 2 COVID-19 vaccinations and who had high WHO HIV Vaccine Positive Attitude Scale scores were, respectively, 3.2 times and 2.4 times more likely to report the intention to vaccinate within one year. Early vaccine adopters were also 2.4 times more likely to feel that HIV prevention support discriminates against African American MSM. Those reporting three or more sexual partners and medical mistrust were, respectively, 60% and 59% more likely to report the intention to delay HIV vaccination. The lack of a knowledge base on HIV vaccine perceptions and acceptability is a missed opportunity to provide guidance on how stakeholders, such as health providers and policymakers, should address HIV vaccine hesitancy once this crucial vaccine is licensed. The key factors affecting vaccine adoption are valuable in developing and implementing campaigns to enhance the HIV vaccine coverage in this vulnerable population. Full article

The Marburg virus (MARV), the virus responsible for Marburg hemorrhagic fever (MHF), is considered a top-priority pathogen for vaccine development. Recent outbreaks in Equatorial Africa have highlighted the urgency of MARV because of its high fatality rate and historical concerns about potential weaponization. Currently, there are no licensed vaccines for MARV. Existing vaccine candidates rely on attenuated recombinant vesicular stomatitis virus carrying MARV glycoprotein (VSVΔG) or the chimpanzee replication-defective adenovirus 3 vector ChAd3-MARV. Although these platforms provide significant protection in animal models, they face challenges because of their limited thermal stability and the need for cold storage during deployment in resource-poor areas. An alternative approach involves using adjuvanted poly (lactic-co-glycolic acid) (PLGA) microparticles loaded with synthetic peptides representing MHC class I—restricted T cell epitopes. This vaccine platform has demonstrated effectiveness in protecting against SARS-CoV-2 and EBoV disease in animal models and has the advantage of not requiring cold storage and remaining stable at room temperature for over six months. This report outlines the design, manufacturing, and in vivo immunogenicity testing of PLGA microparticle human vaccines designed to prevent Marburg hemorrhagic fever. Full article

This study explored the optimum immunization schedule for the quadrivalent influenza split-virion vaccine containing influenza A strains (H1N1 and H3N2) and B lineage strains (Yamagata and Victoria) in children aged 3–8 years. The 652 participants enrolled were divided into two groups based on a history of influenza immunization (IH group) or no history of influenza immunization (NH group). The groups were administered a two-dose immunization schedule on days 0 and 30. In the NH group, on day 30 after the first dose, the positive rates of influenza hemagglutination-inhibition antibodies of strains H1N1, H3N2, BV, and BY were 85.85%, 71.70%, 65.27% and 60.45%, respectively. The positive rates of BV and BY failed to meet the absolute criteria for evaluating the immunogenicity of influenza vaccine in the population aged 3–60 years (for each strain antibody). On day 30 after the second dose, HI antibodies to strains H1N1, H3N2, BV, and BY met the immunogenicity acceptable criteria. In the IH group, on day 30 after the first dose, HI antibodies to strains H1N1, H3N2, BV, and BY met the acceptable criteria for immunogenicity. The incidence rates of adverse reactions (vaccine-related adverse events) from the first dose up until 30 days after the second dose were 20.80% in the IH group and 19.50% in the NH group. Only two Grade 3 adverse reactions (fever: temperature ≥ 39.5 °C, swelling: area ≥ 50% of the injection site area) occurred in the IH group, and no Grade 3 adverse reactions occurred in the NH group. No serious adverse reactions occurred in either group. We conclude that for the NH group, two doses of quadrivalent influenza vaccine should be administered, and for the IH group, a one-dose regimen is acceptable. Full article

Currently, vaccine development against different respiratory diseases is at its peak. It is of utmost importance to find suitajble adjuvants that can increase the potency of the vaccine candidates. This study aimed to determine the systemic and splenic immune mechanisms in mice models induced by anionic and cationic lipid adjuvants in the presence of the vaccine-candidate influenza antigen hemagglutinin (HA). In the presence of the HA antigen, the cationic adjuvant (N3) increased conventional dendritic cell 1 (cDC1) abundance with enhanced MHCI and CD80-CD86 costimulatory marker expression, and significantly higher CD8T and Th17 populations with enhanced interferon-gamma (IFNγ) expression in CD8T and CD4T populations. Conversely, the anionic adjuvant (L3) increased the cDC2 population percentage with significantly higher MHCII and DEC205 expression, along with an increase in the CD4T and regulatory T cell populations. The L3-treated group also exhibited higher percentages of activated B and plasma cell populations with significantly higher antigen-specific IgG and IgA titer and virus neutralization potential. While the anionic adjuvant induced significantly higher humoral responses than the cationic adjuvant, the latter influenced a significantly higher Th1/Th17 response. For customized vaccine development, it is beneficial to have alternative adjuvants that can generate differential immune responses with the same vaccine candidate antigen. This study will aid the selection of adjuvants based on their charges to improve specific immune response arms in the future development of vaccine formulation. Full article

Pertussis is an important cause of mortality and morbidity in infancy. It is recommended that close contacts of the baby be vaccinated with Tdap, and this practice is called the cocoon strategy. This study aimed to investigate the applicability of the cocoon strategy and to determine the factors affecting the process. Mothers of babies who were hospitalized in the neonatal intensive care unit were included in the study. In the first stage, a face-to-face questionnaire was given to the mothers to measure their level of knowledge about whooping cough and its vaccine. In the second stage, written and verbal information about the cocoon strategy was given, and then vaccination intentions for Tdap were learned. In the third stage, all mothers were contacted 3 weeks after and asked whether they had received a Tdap vaccination and why. Of these mothers, 68% could not answer any questions about pertussis disease and vaccines correctly. After the information, 35% (n = 78) of the mothers stated that they were considering getting vaccinated, while only 2% (n = 5) of the mothers were able to get the Tdap vaccine. The most important reasons for not getting vaccinated were a lack of time (24%) and the cost of vaccination (23%). It is predicted that Tdap vaccination rates may increase if the cost of vaccine, availability of vaccine, and the access of mothers to the vaccine application are facilitated. Full article

SARS-CoV-2 virus, the causative agent of COVID-19, has produced the largest pandemic in the 21st century, becoming a very serious health problem worldwide. To prevent COVID-19 disease and infection, a large number of vaccines have been developed and approved in record time, including new vaccines based on mRNA encapsulated in lipid nanoparticles. While mRNA-based vaccines have proven to be safe and effective, they are more expensive to produce compared to conventional vaccines. A special type of mRNA vaccine is based on self-amplifying RNA (saRNA) derived from the genome of RNA viruses, mainly alphaviruses. These saRNAs encode a viral replicase in addition to the antigen, usually the SARS-CoV-2 spike protein. The replicase can amplify the saRNA in transfected cells, potentially reducing the amount of RNA needed for vaccination and promoting interferon I responses that can enhance adaptive immunity. Preclinical studies with saRNA-based COVID-19 vaccines in diverse animal models have demonstrated the induction of robust protective immune responses, similar to conventional mRNA but at lower doses. Initial clinical trials have confirmed the safety and immunogenicity of saRNA-based vaccines in individuals that had previously received authorized COVID-19 vaccines. These findings have led to the recent approval of two of these vaccines by the national drug agencies of India and Japan, underscoring the promising potential of this technology. Full article

Vaccine hesitancy poses a significant threat to the health of individuals across all age groups, which has been exacerbated by the COVID-19 pandemic. In this cross-sectional study, an extension of the Theory of Planned Behavior (TPB) was applied to investigate psychosocial variables predicting intention to vaccinate children under 12 against COVID-19 in a sample of 420 Italian parents (Mean age = 40.4, SD = 5.9; Women = 78.1%). Hierarchical regression analysis revealed that, among the TPB variables, cognitive attitude, descriptive norms, and perceived behavioral control significantly predicted parents’ vaccination intention. Furthermore, including trust in the institutions’ ability to manage the vaccination campaign in the model significantly increased the explained variance in intention. These findings suggest that campaigns promoting childhood COVID-19 vaccination should not only emphasize the safety and effectiveness of vaccines for children but also focus on reducing barriers to vaccination. Additionally, attention should be given to enhancing the perception that this behavior is widespread among other parents, thus leveraging the power of social influence. Finally, and not less important, significant efforts should be directed toward building and reinforcing trust in the system of actors promoting and managing the COVID-19 vaccination campaign. Full article

Dengue virus (DENV) infection continues to be a public health challenge, lacking a specific cure. Vaccination remains the primary strategy against dengue; however, existing live-attenuated vaccines display variable efficacy across four serotypes, influenced by host serostatus and age, and predominantly inducing humoral responses. To address this limitation, this study investigates a multiepitope-based immunogen designed to induce robust cellular immunity across all DENV serotypes. The chimeric immunogen integrates H-2^d specific MHC-I binding T-cell epitopes derived from conserved domains within the DENV envelope protein. Immuno-informatics analyses supported its stability, non-allergenic nature, and strong MHC-I binding affinity as an antigen. To assess the immunogenicity of the multiepitope, it was expressed in murine bone-marrow-derived dendritic cells (BMDCs) that were used to prime mice. In this experimental model, simultaneous exposure to T-cell epitopes from all four DENV serotypes initiated distinct IFNγ-CD8 T-cell responses for different serotypes. These results supported the potential of the multiepitope construct as a vaccine candidate. While the optimization of the immunogen design remains a continuous pursuit, this proof-of-concept study provides a starting point for evaluating its protective efficacy against dengue infection in vivo. Moreover, our results support the development of a multiepitope vaccine that could trigger a pan-serotype anti-dengue CD8 response. Full article

Background: COVID-19 vaccination is the most significant step toward the long-term mitigation of SARS-CoV-2-related complication, avoiding disease and death and decreasing virus spread. This study aimed to evaluate, in a real-world setting, booster dose effectiveness to reduce COVID-19 risk considering the amount of time after the end of the two-dose vaccination cycle. A sub-analysis was conducted to adjust the booster dose effect for occupational and demographic factors. Methods: About 16,000 COVID-19-vaccinated HCWs of three University Hospital Networks in Milan (HN1/HN2/HN3) were included in the study. Data were collected by Occupational Health Physicians of the HNs within specific computerized databases. Results: In univariable analysis, booster dose administration displayed a slightly higher risk of infection with respect to not receiving it, OR = 1.18, with 95% confidence interval (C.I) [0.99, 1.41]. When the model was adjusted with the modulating effect of time from the completion of the vaccination cycle on booster dose administration, the latter resulted in strong protective effect against infection, OR = 0.43, 95% CI [0.26, 0.74]. However, considering the modifying influence of time from the vaccination cycle’s completion, the administration of booster doses appeared to have a protective effect against infection. In HN1, students and resident physicians displayed lower odds of infection with respect to physicians. Lastly, a non-linear effect of age was reported. Conclusions: Our findings suggest that the correct timing in vaccine scheduling and administration is critical to vaccine effectiveness. These findings, applicable to all vaccinations, should help in setting up more effective vaccination strategies. Full article

Somalia is a complex and fragile setting with a demonstrated potential for disruptive, high-burden measles outbreaks. In response, since 2018, Somalian authorities have partnered with UNICEF and the WHO to implement measles vaccination campaigns across the country. In this paper, we create a Somalia-specific model of measles transmission based on a comprehensive epidemiological dataset including case-based surveillance, vaccine registries, and serological surveys. We use this model to assess the impact of these campaign interventions on Somalian’s measles susceptibility, showing, for example, that across the roughly 10 million doses delivered, 1 of every 5 immunized a susceptible child. Finally, we use the model to explore a counter-factual epidemiology without the 2019–2020 campaigns, and we estimate that those interventions prevented over 10,000 deaths. Full article

Burkholderia are a group of Gram-negative bacteria that can cause a variety of diseases in at-risk populations. B. pseudomallei and B. mallei, the etiological agents of melioidosis and glanders, respectively, are the two clinically relevant members of the B. pseudomallei complex (Bpc). The development of vaccines against Bpc species has been accelerated in recent years, resulting in numerous promising subunits and glycoconjugate vaccines incorporating a variety of antigens. However, a second group of pathogenic Burkholderia species exists known as the Burkholderia cepacia complex (Bcc), a group of opportunistic bacteria which tend to affect individuals with weakened immunity or cystic fibrosis. To date, there have been few attempts to develop vaccines to Bcc species. Therefore, the primary goal of this review is to provide a broad overview of the various subunit antigens that have been tested in Bpc species, their protective efficacy, study limitations, and known or suspected mechanisms of protection. Then, we assess the reviewed Bpc antigens for their amino acid sequence conservation to homologous proteins found in Bcc species. We propose that protective Bpc antigens with a high degree of Bpc-to-Bcc sequence conservation could serve as components of a pan-Burkholderia vaccine capable of protecting against both disease-causing groups. Full article

This study assessed IgG levels to influenza/pertussis and neutralizing antibody (Nab) responses of COVID-19 vaccines in blood of pregnant women following immunization with pertussis (Tdap), influenza, and COVID-19 vaccines. We prospectively collected 71 participants categorized by the following vaccine combinations: 3TI, 4TI, 3T, and 4T groups (three and four doses of COVID-19 vaccines plus Tdap/influenza or Tdap vaccines alone). Our findings have indicated that the 3TI group exhibited elevated IgG levels for influenza B compared to the 3T group (12.90 vs. 7.75 U, p = 0.001); this pattern was not observed for influenza A. Pertussis IgG levels remained uniform across all groups. The 4TI group demonstrated a greater Nab inhibition rate from COVID-19 vaccines compared to both the 3TI and 3T groups (61.34% vs. 22.5% and 15.16%, respectively, p = 0.001). We observed no correlation between Nab inhibition rate and IgG levels for Tdap/influenza, with the exception of a moderate correlation with influenza B in the 3TI group. The efficacy of Tdap vaccine in pregnant women remained consistent, regardless of the administration of COVID-19 or influenza vaccines. Interestingly, without the influenza vaccine, both three and four doses of the COVID-19 vaccine still offered protection against influenza A, but not B. Hence, co-administering COVID-19, influenza, and Tdap vaccines during prenatal care maintains immunogenicity and is highly advised to safeguard pregnant women fully. Full article