COVID-19 Vaccine Acceptance and Hesitancy among Pregnant Women: A Knowledge, Attitude, and Perceived Risks Survey in Lusaka, Zambia

Introduction: The coronavirus disease 2019 (COVID-19) is an infectious disease of the respiratory tract caused by SARS-CoV-2. Since its emergence, there have been increased rates of transmission and spread, morbidity and mortality which led to the development of COVID-19 vaccines to address the pandemic. This study assessed acceptance, knowledge, attitude, and perceived risks regarding COVID-19 vaccines among pregnant women attending antenatal care at two First-Level Hospitals in Lusaka, Zambia. Materials and Methods: This was a cross-sectional study that was conducted among 241 pregnant women using a questionnaire from August 2023 to October 2023 in two First-Level Hospitals in Lusaka district, Zambia. The collected data were analyzed using IBM Statistical Package for Social Sciences (SPSS) version 22.0. Statistical analysis was performed using a Chi-square test. The statistical significance was set at a 95% confidence level. Results: Of the 241 participants, 107 (42.7%) were aged between 24 and 34 years. Overall, 64.3% accepted the COVID-19 vaccines, of which 122 (50.6%) were already vaccinated. Further, 203 (84.6%) of the pregnant women had good knowledge, and 199 (82.6%) had positive attitudes towards COVID-19 vaccines. However, 58.5% thought COVID-19 vaccines were not safe and could cause infertility. Alongside this, 70.1% thought that COVID-19 vaccines were harmful during pregnancy. Having good knowledge of COVID-19 vaccines was associated with age (p = 0.049), education status (p = 0.001), and employment status (p = 0.001). Having a positive attitude towards COVID-19 vaccines was associated with education status (p = 0.001) and employment status (p = 0.001). Conclusion: This study found that most pregnant women had good knowledge, and positive attitudes, and the majority accepted the COVID-19 vaccine. Encouragingly, most of the pregnant women who accepted the COVID-19 vaccines were already vaccinated. Most pregnant women thought that COVID-19 vaccines had side effects, were not safe, and could be harmful during pregnancy. Consequently, this could have contributed to the hesitancy to receive a vaccine among some participants. The findings of this study demonstrate the need to provide pregnant women with continuous educational programs on the benefits of vaccinations for themselves and their children.

Recent advances on vaccines against malaria: A review

This review aims to summarize the currently viable vaccine strategies including the approved vaccines and the those in trials for next-generation malaria vaccines.Data on malaria vaccine development was collected through a comprehensive review.The literature search was performed using databases including Google Scholar,PubMed,NIH,and Web of Science.Various novel approaches of vaccination are being developed,including those based on radiation-attenuated strategies,monoclonal antibodies,targeted immunogenic peptides,RNA and DNA vaccines,nanoparticle-based vaccines,protein-based vaccination protocols,and whole organism-based vaccination strategies.Trials on RTS,S have entered phase Ⅲtesting,and those based on blood-stage vaccines and vaccines to interrupt malarial transmission have advanced to higher stages of trials.Mathematical modeling,combined drug and vaccine strategies,mass drug administration,polyvalent vaccine formulations,and targeted vaccination campaigns is playing an important role in malarial prevention.Furthermore,assessing coverage,accessibility,acceptability,deployment,compilation,and adherence to specific vaccination strategies in endemic regions is essential for vaccination drives against malaria.

Adverse Side Effects of COVID-19 Vaccines in Older Adults: A Comprehensive Review of Current Research

The purpose of this research review was to examine current scientific literature on COVID-19 vaccine-induced side effects in older adults. We reviewed studies focusing on side effects categorized into cardiologic, immunologic, neurologic, and ocular groups. Cardiologic side effects included myocarditis, pericarditis, and myocardial infarction. Immunologic conditions examined were anaphylaxis and vaccine-induced immune thrombotic thrombocytopenia. Neurologic side effects included Guillain-Barré syndrome and Bell’s Palsy. Ocular side effects covered ocular swelling, submacular hemorrhage, and corneal graft rejection after keratoplasty and Descemet membrane endothelial keratoplasty. Additionally, less common side effects in older adults were reviewed but found to be statistically rare. Overall, COVID-19 vaccine-induced side effects in elderly populations were rare. We concluded that the vaccine’s efficacy in preventing excess deaths due to COVID-19 is significant, and the risk of these rare side effects does not justify foregoing vaccination in at-risk individuals. Patients at higher risk for these side effects should be informed, and additional considerations should be made by their treating physician. This review aims to increase awareness of rare vaccine-induced side effects to encourage further studies, enhancing understanding of their etiology and prevalence in at-risk older adult populations.

Dengue outbreaks in northern Nigeria: Evaluating the recommended Takeda vaccine and future prevention strategies

Dengue fever,caused by the dengue virus(DENV),poses a significant public health challenge globally,with Nigeria experiencing sporadic outbreaks.A clear understanding of the dengue burden has not been achieved in Nigeria,just as in other African countries.Understanding the epidemiology and burden of dengue fever is essential for effective prevention and control strategies.This paper examines the recent dengue outbreaks in northern Nigeria,particularly in Sokoto state,and evaluates the recommended Takeda dengue vaccine(TDV)along with future prevention strategies.Despite limited surveillance and underreporting,dengue fever is endemic in Nigeria(with over 5 million cases and 5000 dengue-related deaths in 2023),with recent outbreaks indicating a growing concern.The TDV,a live attenuated tetravalent vaccine,has shown promise in preventing dengue fever,but challenges such as vaccine acceptance and access-ibility need to be addressed.Global urbanization contributes to the disease's spread,which is influenced by factors such as population density,cultural beliefs,water storage practices,hygiene,and water supply accessibility.Future prevention strategies must focus on government intervention,community practices,and innovative vector control measures to mitigate the spread of DENV in Nigeria.This study will serve as a valuable reference for policy-makers,researchers,and clinicians in the management and control of DENV in Nigeria and Africa as a whole.

Plant-based vaccines against viral hepatitis: A panoptic review

The traditional vaccines against hepatitis have been instrumental in reducing the incidence of some types of viral hepatitis;however,the need for cost-effective,easily distributable,and needle-free vaccine alternatives has led to the exploration of plant-based vaccines.Plant-based techniques offer a promising avenue for producing viral hepatitis vaccines due to their low-cost cultivation,scalability,and the potential for oral administration.This review highlights the successful expression of hepatitis B surface antigens in plants and the subsequent formation of virus-like particles,which have shown immunogenicity in preclinical and clinical trials.The challenges such as achieving sufficient antigen expression levels,ensuring consistent dosing,and navigating regulatory frameworks,are addressed.The review considers the potential of plant-based vaccines to meet the demands of rapid vaccine deployment in response to outbreaks and their role in global immunization strategies,particularly in resource-limited settings.This review underscores the significant strides made in plant molecular farming and the potential of plant-based vaccines to complement existing immunization methods against viral hepatitis.

Emerging Frontiers in Vaccine Development: A Review of Changing Paradigm

The technology behind vaccine development varies significantly from one vaccine to another depending on the time when the vaccine was first developed. Over the years, the vaccine innovation time has significantly shortened with the advancement of knowledge in the fields of molecular and cell biology, and discoveries in the field of biotechnology. The first vaccines created were tested in a kind of trial-and-error approach which sometimes had deadly side effects. These vaccines used either living, weakened, or completely dead pathogens. The use of whole pathogen vaccines was seen to be time consuming and unpredictable because even though it would cause an immune response, it could vary from person to person, and always had the risk of pathogens returning to virulence causing sometimes fatal outcomes. The next major technology used to create vaccines was subunit vaccines which utilize purified antigens inactivated through various methods. This technology is quite prevalent among the vaccines that are currently in circulation, making them quite effective, and free from fatal side effects. The viral vector vaccine technology has been around for a few decades and utilizes knowledge of molecular genetics to the greatest extent. It uses intermediate vectors to deliver genetic instructions to trigger an immune response within the subject body. The introduction of nucleic acid vaccines is the newest technology and has come to a great deal of attention during the SARS-CoV-2 immunization efforts. The technology primarily utilizes the delivery of genetic information using messenger ribonucleic acid (mRNA) to create characteristic pathogen-specific proteins that in turn generate an immune response in the recipients.

Clinical application of COVID-19 vaccine in liver transplant recipients

Background:Solid organ transplant(SOT)activities,such as liver transplant,have been greatly influenced by the pandemic of coronavirus disease 2019(COVID-19),a disease caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Immunosuppressed individuals of liver transplant recipients(LTRs)tend to have a high risk of COVID-19 infection and related complications.Therefore,COVID-19 vaccination has been recommended to be administered as early as possible in LTRs.Data sources:The keywords“liver transplant”,“SARS-CoV-2”,and“vaccine”were used to retrieve articles published in PubMed.Results:The antibody response following the 1st and 2nd doses of vaccination was disappointingly low,and the immune responses among LTRs remarkably improved after the 3rd or 4th dose of vaccination.Although the 3rd or 4th dose of COVID-19 vaccine increased the antibody titer,a proportion of patients remained unresponsive.Furthermore,recent studies showed that SARS-CoV-2 vaccine could trigger adverse events in LTRs,including allograft rejection and liver injury.Conclusions:This review provides the recently reported data on the antibody response of LTRs following various doses of vaccine,risk factors for poor serological response and adverse events after vaccination.

Overcoming neutrophil-induced immunosuppression in postoperative cancer therapy: Combined sialic acid-modified liposomes with scaffold-based vaccines

Immunotherapy is a promising approach for preventing postoperative tumor recurrence and metastasis. However, inflammatory neutrophils, recruited to the postoperative tumor site, have been shown to exacerbate tumor regeneration and limit the efficacy of cancer vaccines. Consequently, addressing postoperative immunosuppression caused by neutrophils is crucial for improving treatment outcomes. This study presents a combined chemoimmunotherapeutic strategy that employs a biocompatible macroporous scaffold-based cancer vaccine (S-CV) and a sialic acid (SA)-modified, doxorubicin (DOX)-loaded liposomal platform (DOX@SAL). The S-CV contains whole tumor lysates as antigens and imiquimod (R837, Toll-like receptor 7 activator)-loaded PLGA nanoparticles as immune adjuvants for cancer, which enhance dendritic cell activation and cytotoxic T cell proliferation upon localized implantation. When administered intravenously, DOX@SAL specifically targets and delivers drugs to activated neutrophils in vivo, mitigating neutrophil infiltration and suppressing postoperative inflammatory responses. In vivo and vitro experiments have demonstrated that S-CV plus DOX@SAL, a combined chemo-immunotherapeutic strategy, has a remarkable potential to inhibit postoperative local tumor recurrence and distant tumor progression, with minimal systemic toxicity, providing a new concept for postoperative treatment of tumors.

Mycobacterium smegmatis enhances shikonin-induced immunogenic cell death—an efficient in situ tumor vaccine strategy

Tumor vaccines are a promising avenue in cancer immunotherapy.Despite the progress in targeting specific immune epitopes,tumor cells lacking these epitopes can evade the treatment.Here,we aimed to construct an efficient in situ tumor vaccine called Vac-SM,utilizing shikonin(SKN)to induce immunogenic cell death(ICD)and Mycobacterium smegmatis as an immune adjuvant to enhance in situ tumor vaccine efficacy.SKN showed a dose-dependent and time-dependent cytotoxic effect on the tumor cell line and induced ICD in tumor cells as evidenced by the CCK-8 assay and the detection of the expression of relevant indicators,respectively.Compared with the control group,the in situ Vac-SM injection in mouse subcutaneous metastatic tumors significantly inhibited tumor growth and distant tumor metastasis,while also improving survival rates.Mycobacterium smegmatis effectively induced maturation and activation of bone marrow-derived dendritic cells(DCs),and in vivo tumor-draining lymph nodes showed an increased maturation of DCs and a higher proportion of effector memory T-cell subsets with the Vac-SM treatment,based on flow cytometry analysis results.Collectively,the Vac-SM vaccine effectively induces ICD,improves antigen presentation by DCs,activates a specific systemic antitumor T-cell immune response,exhibits a favorable safety profile,and holds the promise for clinical translation for local tumor immunotherapy.

Advances in Zika virus vaccines and therapeutics:A systematic review

Zika virus(ZIKV)is the causative agent of a viral infection that causes neurological complications in newborns and adults worldwide.Its wide transmission route and alarming spread rates are of great concern to the scientific community.Numerous trials have been conducted to develop treatment options for ZIKV infection.This review highlights the latest developments in the fields of vaccinology and pharmaceuticals developments for ZIKV infection.A systematic and comprehensive approach was used to gather relevant and up-to-date data so that inferences could be made about the gaps in therapeutic development.The results indicate that several therapeutic interventions are being tested against ZIKV infection,such as DNA vaccines,subunit vaccines,live-attenuated vaccines,virus-vector-based vaccines,inactivated vaccines,virus-like particles,and mRNA-based vaccines.In addition,approved anti-ZIKV drugs that can reduce the global burden are discussed.Although many vaccine candidates for ZIKV are at different stages of development,none of them have received Food and Drug Authority approval for use up to now.The issue of side effects associated with these drugs in vulnerable newborns and pregnant women is a major obstacle in the therapeutic pathway.

Therapeutic tumor vaccines-a rising star to benefit cancer patients

Malignant tumors are still a worldwide threat to human health.Tumor treatment strategies are constantly evolving,and the advent of tumor immunotherapy has brought up hope to many types of tumors,especially for those that are refractory to conventional therapies including surgery,radiotherapy,and chemotherapy.Tumor vaccines can initiate or amplify an anti-tumor immune response in tumor patients through active immunization,and therefore occupy an important position in tumor immunotherapy.The main types of tumor vaccines include tumor cell vaccines,dendritic cell vaccines,polypeptide vaccines and nucleic acid vaccines.Due to factors such as poor antigen selection and suppressive tumor microenvironment,earliest tumor vaccines on clinical trials failed to achieve satisfactory clinical effects.However,with the development of second-generation genome sequencing technologies and bioinformatics tools,it is possible to predict neoantigens generated by tumor-specific mutations and therefore prepare personalized vaccines.This article summarizes the global efforts in developing tumor vaccines and highlights several representative tumor vaccines in each category.

Mucosal COVID-19 vaccines:Risks,benefits and control of the pandemic

Based on mucosal immunization to promote both mucosal and systemic immune responses,next-generation coronavirus disease 2019(COVID-19)vaccines would be administered intranasally or orally.The goal of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)vaccines is to provide adequate immune protection and avoid severe disease and death.Mucosal vaccine candidates for COVID-19 including vector vaccines,recombinant subunit vaccines and live attenuated vaccines are under development.Furthermore,subunit protein vaccines and virus-vectored vaccines have made substantial progress in preclinical and clinical settings,resulting in SARS-CoV-2 intranasal vaccines based on the previously successfully used nasal vaccines.Additional to their ability to trigger stable,protective immune responses at the sites of pathogenic infection,the development of‘specific’mucosal vaccines targeting coronavirus antigens could be an excellent option for preventing future pandemics.However,their efficacy and safety should be confirmed.

Neoantigen cancer vaccines:a new star on the horizon

Immunotherapy represents a promising strategy for cancer treatment that utilizes immune cells or drugs to activate the patient's own immune system and eliminate cancer cells.One of the most exciting advances within this field is the targeting of neoantigens,which are peptides derived from non-synonymous somatic mutations that are found exclusively within cancer cells and absent in normal cells.Although neoantigen-based therapeutic vaccines have not received approval for standard cancer treatment,early clinical trials have yielded encouraging outcomes as standalone monotherapy or when combined with checkpoint inhibitors.Progress made in high-throughput sequencing and bioinformatics have greatly facilitated the precise and efficient identification of neoantigens.Consequently,personalized neoantigen-based vaccines tailored to each patient have been developed that are capable of eliciting a robust and long-lasting immune response which effectively eliminates tumors and prevents recurrences.This review provides a concise overview consolidating the latest clinical advances in neoantigen-based therapeutic vaccines,and also discusses challenges and future perspectives for this innovative approach,particularly emphasizing the potential of neoantigen-based therapeutic vaccines to enhance clinical efficacy against advanced solid tumors.

A novel live attenuated vaccine candidate protects chickens against subtype B avian metapneumovirus

Avian metapneumovirus(aMPV) is a highly contagious pathogen that causes acute upper respiratory tract diseases in chickens and turkeys, resulting in serious economic losses. Subtype B aMPV has recently become the dominant epidemic strain in China. We developed an attenuated aMPV subtype B strain by serial passaging in Vero cells and evaluated its safety and efficacy as a vaccine candidate. The safety test showed that after the 30th passage, the LN16-A strain was fully attenuated, as clinical signs of infection and histological lesions were absent after inoculation.The LN16-A strain did not revert to a virulent strain after five serial passages in chickens. The genomic sequence of LN16-A differed from that of the parent wild-type LN16(wtLN16) strain and had nine amino acid mutations. In chickens, a single immunization with LN16-A induced robust humoral and cellular immune responses, including the abundant production of neutralizing antibodies, CD4^(+) T lymphocytes, and the Th1(IFN-γ) and Th2(IL-4 and IL-6)cytokines. We also confirmed that LN16-A provided 100% protection against subtype B aMPV and significantly reduced viral shedding and turbinate inflammation. Our findings suggest that the LN16-A strain is a promising live attenuated vaccine candidate that can prevent infection with subtype B aMPV.

Immunogenicity Evaluation of a SARS-CoV-2 BA.2 Subunit Vaccine Formulated with CpG 1826 plus alum Dual Adjuvant

Objective The present study aimed to evaluate the immunogenicity of BA.2 variant receptor binding domain(RBD)recombinant protein formulated with CpG 1826 plus alum dual adjuvant.Methods The BA.2 variant RBD(residues 308-548)fusing TT-P2 epitope was obtained from prokaryotic expression system,purification technology and dialysis renaturation,which was designated as Sot protein.The soluble Sot protein formulated with CpG 1826 plus alum dual adjuvant was designated as Sot/CA subunit vaccine and then the BALB/c mice were intramuscularly administrated with two doses of the Sot/CA subunit vaccine at 14-day interval(day 0 and 14).On day 28,the number of effector T lymphocytes secreting IFN-γand IL-4 in mice spleen were determined by enzyme-linked immunospot(ELISpot)assay.The serum IgG,IgG1 and IgG2a antibodies were examined by enzyme-linked immunosorbent assay(ELISA).In addition,the level of neutralizing antibodies(NAbs)induced by Sot/CA subunit vaccine was also evaluated by the microneutralization assay.Results The high-purity soluble Sot protein with antigenicity was successfully obtained by the prokaryotic expression,protein purification and dialysis renaturation.The Sot/CA subunit vaccine induced a high level of IgG antibodies and NAbs,which were of cross-neutralizing activity against SARS-CoV-2 BA.2 and XBB.1.5 variants.Meanwhile,Sot/CA subunit vaccine also induced a high level of effector T lymphocytes secreting IFN-γ(635.00±17.62)and IL-4(279.20±13.10),respectively.Combined with a decreased IgG1/IgG2a ratio in the serum,which indicating Sot/CA subunit vaccine induced a Th1-type predominant immune response.Conclusion The Sot protein formulated with CpG 1826 plus alum dual adjuvant showed that the excellent cellular and humoral immunogenicity,which provided a scientific basis for the development of BA.2 variant subunit vaccines and references for the adjuvant application of subunit vaccines.

Antibodies elicited by Newcastle disease virus-vectored H7N9 avian influenza vaccine are functional in activating the complement system

H7N9 subtype avian influenza virus poses a great challenge for poultry industry.Newcastle disease virus(NDV)-vectored H7N9 avian influenza vaccines(NDV_(vec)H7N9)are effective in disease control because they are protective and allow mass administration.Of note,these vaccines elicit undetectable H7N9-specific hemagglutination-inhibition(HI)but high IgG antibodies in chickens.However,the molecular basis and protective mechanism underlying this particular antibody immunity remain unclear.Herein,immunization with an NDV_(vec)H7N9 induced low anti-H7N9 HI and virus neutralization titers but high levels of hemagglutinin(HA)-binding IgG antibodies in chickens.Three residues(S150,G151 and S152)in HA of H7N9 virus were identified as the dominant epitopes recognized by the NDV_(vec)H7N9 immune serum.Passively transferred NDV_(vec)H7N9 immune serum conferred complete protection against H7N9 virus infection in chickens.The NDV_(vec)H7N9 immune serum can mediate a potent lysis of HA-expressing and H7N9 virus-infected cells and significantly suppress H7N9 virus infectivity.These activities of the serum were significantly impaired after heat-inactivation or treatment with complement inhibitor,suggesting the engagement of the complement system.Moreover,mutations in the 150-SGS-152 sites in HA resulted in significant reductions in cell lysis and virus neutralization mediated by the NDV_(vec)H7N9 immune serum,indicating the requirement of antibody-antigen binding for complement activity.Therefore,antibodies induced by the NDV_(vec)H7N9 can activate antibody-dependent complement-mediated lysis of H7N9 virus-infected cells and complement-mediated neutralization of H7N9 virus.Our findings unveiled a novel role of the complement in protection conferred by the NDV_(vec)H7N9,highlighting a potential benefit of engaging the complement system in H7N9 vaccine design.

mRNA vaccines:a new era in vaccine development

The advent of RNA therapy,particularly through the development of mRNA cancer vaccines,has ushered in a new era in the field of oncology.This article provides a concise overview of the key principles,recent advancements,and potential implications of mRNA cancer vaccines as a groundbreaking modality in cancer treatment.mRNA cancer vaccines represent a revolutionary approach to combatting cancer by leveraging the body’s innate immune system.These vaccines are designed to deliver specific mRNA sequences encoding cancer-associated antigens,prompting the immune system to recognize and mount a targeted response against malignant cells.This personalized and adaptive nature of mRNA vaccines holds immense potential for addressing the heterogeneity of cancer and tailoring treatments to individual patients.Recent breakthroughs in the development of mRNA vaccines,exemplified by the success of COVID-19 vaccines,have accelerated their application in oncology.The mRNA platform’s versatility allows for the rapid adaptation of vaccine candidates to various cancer types,presenting an agile and promising avenue for therapeutic intervention.Clinical trials of mRNA cancer vaccines have demonstrated encouraging results in terms of safety,immunogenicity,and efficacy.Pioneering candidates,such as BioNTech’s BNT111 and Moderna’s mRNA-4157,have exhibited promising outcomes in targeting melanoma and solid tumors,respectively.These successes underscore the potential of mRNA vaccines to elicit robust and durable anti-cancer immune responses.While the field holds great promise,challenges such as manufacturing complexities and cost considerations need to be addressed for widespread adoption.The development of scalable and cost-effective manufacturing processes,along with ongoing clinical research,will be pivotal in realizing the full potential of mRNA cancer vaccines.Overall,mRNA cancer vaccines represent a cutting-edge therapeutic approach that holds the promise of transforming cancer treatment.As research progresses,addressing challenges and refining manufacturing processes will be crucial in advancing these vaccines from clinical trials to mainstream oncology practice,offering new hope for patients in the fight against cancer.

Toward innovative veterinary nanoparticle vaccines

Nanoparticles are significant for veterinary vaccine development because they are safer and more effective than conventional formulations.One promising area of research involves self-assembled protein nanoparticles(SAPNs),which have shown potential for enhancing antigen-presenting cell uptake,B-cell activation,and lymph node trafficking.Numerous nanovaccines have been utilized in veterinary medicine,including natural self-assembled protein nanoparticles,rationally designed self-assembled protein nanoparticles,animal virus-derived nanoparticles,bacteriophagederived nanoparticles,and plant-derived nanoparticles,which will be discussed in this review.SAPN vaccines can produce robust cellular and humoral immune responses and have been shown to protect against various animal infectious diseases.This article attempts to summarize these diverse nanovaccine types and their recent research progress in the field of veterinary medicine.Furthermore,this paper highlights their disadvantages and methods for improving their immunogenicity.

Vaccine pricing and production capacity in Africa: can Africa move beyond pooled procurement in the face of a future pandemic?

We examine Africa's vaccine manufacturing potential,spurred by the coronavirus disease 2019(COVID-19)pan-demic,while critically analyzing vaccine price inequities and procurement strategies during the pandemic,with anticipation of future outbreaks.Although Africa consumes approximately 25%of the global vaccine supply,over 99%of these vaccines are produced outside the continent,primarily due to insufficient local investment.Vaccine procurement strategies have relied heavily on pooled procurement mechanisms and tiered-pricing mod-els,predominantly controlled by external organizations.Significant disparities in vaccine pricing have resulted in vaccine price inequities,with evidence suggesting price discrimination,where different prices are charged for the same vaccine across countries and regions.While vaccine prices are only one component of vaccination cam-paign costs,the inequitable pricing of vaccines poses serious challenges to fair access,especially in low-income countries.Given the inevitability of future pandemics and other outbreaks,the central question remains:Does Africa possess the capacity to strengthen its vaccine production infrastructure and reduce dependency on ex-ternal suppliers?Our review reveals that,with robust political commitment,enhanced investment in Research and Development,and leveraging the heterogeneous nature of the regional bloc,Africa has made strides toward establishing vaccine manufacturing hubs with the potential for substantial capacity expansion.Furthermore,we argue for a regional campaign based on the principles of the fair priority model as an ethical framework for vaccine procurement,which prioritizes need and ensures equitable distribution,thereby complementing existing pooled procurement arrangements in times of future pandemics.This paper concludes with two key recommen-dations based on lessons learned from the COvID-19 crisis and future preparedness.First,Africa must push for a transparent and equitable tiered-pricing structure to ensure affordability for all Second,intentional and sustained investment in R&D is critical to addressing systemic inequities in vaccine supply,not only for cOVID-19 but for future outbreaks and routine immunization programs.

In vivo fluorescence flow cytometry reveals that the nanoparticle tumor vaccine OVA@HA-PEI effectively clears circulating tumor cells

Tumor vaccine therapy offers significant advantages over conventional treatments,including reduced toxic side effects.However,it currently functions primarily as an adjuvant treatment modality in clinical oncology due to limitations in tumor antigen selection and delivery methods.Tumor vaccines often fail to elicit a sufficiently robust immune response against progressive tumors,thereby limiting their clinical efficacy.In this study,we developed a nanoparticle-based tumor vaccine,OVA@HA-PEI,utilizing ovalbumin(OVA)as the presenting antigen and hyaluronic acid(HA)and polyethyleneimine(PEI)as adjuvants and carriers.This formulation significantly enhanced the proliferation of immune cells and cytokines,such as CD3,CD8,interferon-,and tumor necrosis factor-,in vivo,effectively activating an immune response against B16–F10 tumors.In vivofluorescenceflow cytometry(IVFC)has already become an effective method for monitoring circulating tumor cells(CTCs)due to its direct,noninvasive,and long-term detection capabilities.Our study utilized a laboratory-constructed IVFC system to monitor the immune processes induced by the OVA@HA-PEI tumor vaccine and an anti-programmed death-1(PD-1)antibody.The results demonstrated that the combined treatment of OVA@HA-PEI and anti-PD-1 antibody significantly improved the survival time of mice compared to anti-PD-1 antibody treatment alone.Additionally,this combination therapy substantially reduced the number of CTCs in vivo,increased the clearance rate of CTCs by the immune system,and slowed tumor progression.Thesefindings greatly enhance the clinical application prospects of IVFC and tumor vaccines.