A formulated poly (I:C)/CCL21 as an effective mucosal adjuvant for gamma-irradiated influenza vaccine

Background Several studies on gamma-irradiated influenza A virus (γ-Flu) have revealed its superior efficacy for inducing homologous and heterologous virus-specific immunity. However, many inactivated vaccines, notably in nasal delivery, require adjuvants to increase the quality and magnitude of vaccine responses. Methods To illustrate the impacts of co-administration of the gamma-irradiated H1N1 vaccine with poly (I:C) and recombinant murine CCL21, either alone or in combination with each other, as adjuvants on the vaccine potency, mice were inoculated intranasally 3 times at one-week interval with γ-Flu alone or with any of the three adjuvant combinations and then challenged with a high lethal dose (10 LD50) of A/PR/8/34 (H1N1) influenza virus. Virus-specific humoral, mucosal, and cell-mediated immunity, as well as cytokine profiles in the spleen (IFN-γ, IL-12, and IL-4), and in the lung homogenates (IL-6 and IL-10) were measured by ELISA. The proliferative response of restimulated splenocytes was also determined by MTT assay. Results The findings showed that the co-delivery of the γ-Flu vaccine and CCL21 or Poly (I:C) significantly increased the vaccine immunogenicity compared to the non-adjuvanted vaccine, associated with more potent protection following challenge infection. However, the mice given a combination of CCL21 with poly (I:C) had strong antibody- and cell-mediated immunity, which were considerably higher than responses of mice receiving the γ-Flu vaccine with each adjuvant separately. This combination also reduced inflammatory mediator levels (notably IL-10) in lung homogenate samples. Conclusions The results indicate that adjuvantation with the CCL21 and poly (I:C) can successfully induce vigorous vaccine-mediated protection, suggesting a robust propensity for CCL21 plus poly (I:C) as a potent mucosal adjuvant.

Design of the Recombinant Influenza Neuraminidase Antigen is Crucial for its Biochemical Properties and Protective Efficacy

Supplementing influenza vaccines with recombinant neuraminidase (rNA) antigens remains a promising approach for improving the suboptimal vaccine efficacy. However, correlations among rNA designs, properties, and protection have not been systematically investigated. Here, we performed a comparative analysis of several rNAs produced using the baculovirus/insect cell system. The rNAs were designed with different tetramerization motifs and NA domains from a recent H1N1 vaccine strain (A/Brisbane/02/2018) and were compared for enzymatic property, antigenicity, stability, and protection in mice. We found that distinct enzymatic properties are associated with rNAs containing the NA head-domain versus the full-ectodomain, formation of higher order rNA oligomers is tetramerization domain-dependent, whereas protective efficacy is more contingent on the combination of the tetramerization and NA domains. Following single-dose immunizations, a rNA possessing the full-ectodomain and the tetramerization motif from the human vasodilator-stimulated phosphoprotein provided much better protection than a rNA with ∼10-fold more enzymatically active molecules that is comprised of the head-domain and the same tetramerization motif. In contrast, these two rNA designs provided comparable protection when the tetramerization motif from the tetrabrachion protein was used instead. These findings demonstrate that individual rNAs should be thoroughly evaluated for vaccine development, as the heterologous domain combination can result in rNAs with similar key attributes but vastly differ in protection. IMPORTANCE For several decades it has been proposed that influenza vaccines could be supplemented with recombinant neuraminidase (rNA) to improve the efficacy. However, some key questions for manufacturing stable and immunogenic rNA remain to be answered. We show here that the tetramerization motifs and NA domains included in the rNA construct design can have a profound impact on the biochemical, immunogenic and protective properties. We also show that the single-dose immunization regimen is more informative for assessing the rNA immune response and protective efficacy, which is surprisingly more dependent on the specific combination of NA and tetramerization domains than common attributes for evaluating NA. Our findings may help to optimize the design of rNAs that can be used to improve or develop influenza vaccines.

Helminth infection is associated with dampened cytokine responses to viral and bacterial stimulations in Tsimane hunter-horticulturalists

BackgroundSoil-transmitted helminth (STH) infections can catalyze immunological changes that affect the response to subsequent infections, particularly those that elicit strong inflammatory responses. As globalization heightens the risk that remote communities with high STH prevalence will encounter novel pathogens, understanding how STHs shape immune responses to these downstream infections becomes increasingly crucial.MethodologyWe worked with Tsimane forager-horticulturalists in the Bolivian Amazon, where STHs are prevalent. We tested whether STHs and eosinophil levels—most likely indicative of infection in this population—are associated with dampened immune responses to in vitro stimulation with H1N1 and lipopolysaccharide (LPS) antigens. Whole blood samples (n = 179) were treated with H1N1 vaccine and LPS and assayed for 13 cytokines (interferon gamma [INF-γ], interleukin [IL]-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p70, IL-13, Granulocyte-macrophage colony-stimulating factor [GM-CSF], and Tumor necrosis factor-alpha [TNF-α]). We evaluated how STHs and eosinophil levels affected cytokine responses and T helper (Th) 1 and Th2-cytokine suite responses to stimulation.ResultsInfection with Ascaris lumbricoides was significantly (p ≤ 0.05) associated with lower response of some cytokines to H1N1 and LPS in women. Eosinophils were significantly negatively associated with some cytokine responses to H1N1 and LPS, with the strongest effects in women, and associated with a reduced Th1- and Th2-cytokine response to H1N1 and LPS in women and men.Conclusions and implicationsWe find that STHs were associated with dampened cytokine responses to certain viral and bacterial antigens, and suggest that this mitigation of host-induced damage may reduce the incidence of cytokine storms in populations with high STH prevalence.

COVID-19 Vaccine Acceptability and Hesitancy in Africa: Implications for Addressing Vaccine Hesitancy

Background: Increased acceptance and uptake of Coronavirus Disease 2019 (COVID-19) vaccines is very essential in containing the ongoing COVID-19 pandemic. Vaccine hesitancy is a threat to public health containment of infectious diseases. Aim: The main aim of this study was to review published articles regarding COVID-19 vaccine acceptability and hesitancy across all populations in Africa. Materials and methods: This was a narrative review. A comprehensive literature search was done using PubMed, Google Scholar, Scopus, and EMBASE using the keywords vaccine acceptability, vaccine hesitancy, COVID-19 vaccine, COVID-19 pandemic, H1N1 vaccine, swine flu, swine flu vaccine, Africa, and the Boolean word AND. The cited literature was published between March 2001 and June 2021. Results: The few studies were done in Africa so far are among healthcare workers and medical students. Acceptance of vaccination against COVID-19 in Africa ranged from 15.4% to 55.9%. This shows increased hesitancy to receive the COVID-19 vaccines in African countries. Many people were concerned about the potential adverse effects and ineffectiveness of COVID-19 vaccines. Misinformation about the COVID-19 vaccines has contributed to the hesitancy reported from different studies. Moreover, sociodemographic characteristics were also predictors of the acceptability of COVID-19 vaccines. Conclusion: Low acceptability rates reported in Africa indicates increased hesitancy to vaccination against COVID-19. The low acceptance of vaccines in Africa can hinder the required 60-70% vaccinations to achieve herd immunity. Therefore, there is a need to develop strategies that will address hesitancy against the COVID-19 vaccines across countries and populations in Africa and the entire globe.

Use of hemagglutinin and neuraminidase amplicon-based high-throughput sequencing with variant analysis to detect co-infection and resolve identical consensus sequences of seasonal influenza in a university setting

Background Local transmission of seasonal influenza viruses (IVs) can be difficult to resolve. Here, we study if coupling high-throughput sequencing (HTS) of hemagglutinin (HA) and neuraminidase (NA) genes with variant analysis can resolve strains from local transmission that have identical consensus genome. We analyzed 24 samples collected over four days in January 2020 at a large university in the US. We amplified complete hemagglutinin (HA) and neuraminidase (NA) genomic segments followed by Illumina sequencing. We identified consensus complete HA and NA segments using BLASTn and performed variant analysis on strains whose HA and NA segments were 100% similar. Results Twelve of the 24 samples were PCR positive, and we detected complete HA and/or NA segments by de novo assembly in 83.33% (10/12) of them. Similarity and phylogenetic analysis showed that 70% (7/10) of the strains were distinct while the remaining 30% had identical consensus sequences. These three samples also had IAV and IBV co-infection. However, subsequent variant analysis showed that they had distinct variant profiles. While the IAV HA of one sample had no variant, another had a T663C mutation and another had both C1379T and C1589A. Conclusion In this study, we showed that HTS coupled with variant analysis of only HA and NA genes can help resolve variants that are closely related. We also provide evidence that during a short time period in the 2019–2020 season, co-infection of IAV and IBV occurred on the university campus and both 2020/2021 and 2021/2022 WHO recommended H1N1 vaccine strains were co-circulating.

The Importance of Pharmacy Partnerships in Effective COVID-19 Vaccine Distribution

Narrative Abstract The goal of vaccinating the majority of Americans against COVID-19 in a timely manner requires a robust federal vaccine distribution plan involving pharmacy partnerships. Previously, the 2009 Centers for Disease Control and Prevention (CDC) H1N1 Vaccine Pharmacy Initiative resulted in approximately 10% of adults who received a vaccine during the 2009 pandemic reporting they were vaccinated at a pharmacy. This proportion has already largely increased for COVID-19 vaccinations, with the U.S. Department of Health and Human Services (HHS) using similar channels for vaccination as existing partnerships with national pharmacy and grocery retail chains for the COVID-19 Community-Based Testing Program. It continues to prove crucial that the Biden Administration’s national COVID-19 vaccine distribution plan, including the Federal Retail Pharmacy Program, focus on ensuring equitable vaccine distribution and access in medically underserved areas and to vulnerable populations, enabling maximum uptake of COVID-19 vaccines.

Assessment of Factors Affecting Inactivated COVID-19 (CORONAVAC) Vaccine Response and Antibody Response in Healthcare Professionals

BackgroundAlthough COVID-19 pandemic Phase III trial results of many vaccines were reported, the literature about community results is inadequate. This study aims to evaluate the experience gained during the vaccination process of healthcare workers (HCW), the measured antibody responses and the factors affecting the response, and to contribute to the literature in this field by presenting the data. MethodAnti-RBD anti-SARS Cov2 IgG antibodies were measured by the ELISA method in blood samples taken at least a month after the second vaccine from 264 HCW vaccinated twice with an interval of 28 days. Information from individuals were collected with an online participation form. Results264 HCW (166 females (63%), 98 males (37%)) were included in the study whose age are between 23-69 (mean 44.22 ± 11.58). After vaccination, 22 (8.3%) were unresponsive, 25 (9.5%) had weak response, and 217 (82.2%) had a response. The overall rate of weak response and the high response was 91.6%. In our study, that the antibody response was found to be statistically significantly lower in males (p: 0.022), there was a significant decrease in antibody response with advanced age (p <0.005), and the difference was highly significant (p: 0.0005) above the age of 60.ConclusionIn this study, 91.6% anti spike antibodies were detected with CoronaVac which an inactivated vaccine and the antibody response is was lower in cases of advanced age, male gender, not having COVID-19, not developing PVAE, and having pandemic H1N1 vaccine.

Design of the recombinant influenza neuraminidase antigen is crucial for protective efficacy

Supplementing influenza vaccines with recombinant neuraminidase (rNA) remains a promising approach for improving the suboptimal efficacy. However, correlations among rNA designs, properties, and protection have not been systematically investigated. Here, we performed a comparative analysis of several rNAs produced from different construct designs using the baculovirus/insect cell system. The rNAs were designed with different tetramerization motifs and NA domains from a recent H1N1 vaccine strain (A/Brisbane/02/2018) and were analyzed for enzymatic properties, antigenicity, thermal and size stability, and protection in mice. We found that rNAs containing the NA head-domain versus the full-ectodomain possess distinct enzymatic properties and that the molecular size stability is tetramerization domain-dependent, whereas protection is more contingent on the combination of the tetramerization and NA domains. Following single-dose immunizations, a rNA possessing the full-ectodomain, non-native enzymatic activity, and the tetramerization motif from the human vasodilator-stimulated phosphoprotein provided substantially higher protection than a rNA possessing the head-domain, native activity and the same tetramerization motif. In contrast, these two rNAs provided comparable protection when the tetramerization motif was exchanged with the one from the tetrabrachion protein. These findings demonstrate that the rNA design is crucial for the protective efficacy and should be thoroughly evaluated for vaccine development, as the unpredictable nature of the heterologous domain combination can result in rNAs with similar key attributes but vastly differ in protection.

Balancing the influenza neuraminidase and hemagglutinin responses by exchanging the vaccine virus backbone

Virions are a common antigen source for many viral vaccines. One limitation to using virions is that the antigen abundance is determined by the content of each protein in the virus. This caveat especially applies to viral-based influenza vaccines where the low abundance of the neuraminidase (NA) surface antigen remains a bottleneck for improving the NA antibody response. Our systematic analysis using recent H1N1 vaccine antigens demonstrates that the NA to hemagglutinin (HA) ratio in virions can be improved by exchanging the viral backbone internal genes, especially the segment encoding the polymerase PB1 subunit. The purified inactivated virions with higher NA content show a more spherical morphology, a shift in the balance between the HA receptor binding and NA receptor release functions, and induce a better NA inhibitory antibody response in mice. These results indicate that influenza viruses support a range of ratios for a given NA and HA pair which can be used to produce viral-based influenza vaccines with higher NA content that can elicit more balanced neutralizing antibody responses to NA and HA.