Primary care physician perspectives on providing adult vaccines

Recently, several new vaccines have been recommended for adults. Little is known regarding the immunization purchase and stocking practices of adult primary care physicians. To determine the proportion of family practice and internal medicine physicians who routinely stock specific adult vaccines and their rationale for those decisions, we conducted a cross-sectional survey in 2009 of a national random sample of 993 family physicians (FPs) and 997 general internists (IMs) in the US. Of the 1109 respondents, 886 reported that they provide primary care to adults aged 19-64 years and 96% of these physicians stock at least one vaccine recommended for adults. Of those, 2% plan to stop and 12% plan to increase vaccine purchases; the rest plan to maintain status quo. Of the respondents, 27% (31% FPs vs 20% IMs) stocked all adult vaccines. We conclude that many primary care physicians who provide care to adults do not stock all recommended immunizations. Efforts to improve adult immunization rates must address this fundamental issue.     

Approved but non-funded vaccines: Accessing individual protection

Funded immunization programs are best able to achieve high participation rates, optimal protection of the target population, and indirect protection of others. However, in many countries public funding of approved vaccines can be substantially delayed, limited to a portion of the at-risk population or denied altogether. In these situations, unfunded vaccines are often inaccessible to individuals at risk, allowing potentially avoidable morbidity and mortality to continue to occur. We contend that private access to approved but unfunded vaccines should be reconsidered and encouraged, with recognition that individuals have a prerogative to take advantage of a vaccine of potential benefit to them whether it is publicly funded or not. Moreover, numbers of “approved but unfunded” vaccines are likely to grow because governments will not be able to fund all future vaccines of potential benefit to some citizens. New strategies are needed to better use unfunded vaccines even though the net benefits will fall short of those of funded programs.     

The efficacy of a novel vaccine approach using tumor cells that ectopically express a codon-optimized murine GM-CSF in a murine tumor model

Granulocyte macrophage-colony stimulating factor (GM-CSF) is a potent immunomodulatory cytokine that is known to facilitate vaccine efficacy by promoting the development and prolongation of both humoral and cellular immunity. Here, we investigated a novel vaccine approach using a human papillomavirus (HPV)-16 E6/E7-transformed cell line, TC-1, that ectopically expresses a codon-optimized 26-11-2015 murine GM-CSF (cGM-CSF). Ectopically expressing cGM-CSF in TC-1 (TC-1/cGM) cells significantly increased expression of a GM-CSF that was functionally identical to wt GM-CSF by 9-fold compared with ectopically expressed wild type GM-CSF in TC-1 cells (TC-1/wt). Mice vaccinated with irradiated TC-1/cGM cells exhibited enhanced survival compared with mice vaccinated with TC-1/wt cells when both groups were subsequently injected with live TC-1. Consistently, mice vaccinated with irradiated TC-1/cGM cells exhibited stronger IFN-γ production in HPV E7-specific CD8⁺ T cells. More dendritic cells were recruited to the draining lymph nodes (dLNs) of mice vaccinated with TC-1/cGM cells than C-1/wt cells. Regarding dLN cell recall responses, both proliferation and IFN-γ production in the HPV E7-specific CD8⁺ T cells were enhanced in mice that were vaccinated with TC-1/cGM cells. Our results demonstrate that a novel practical molecular strategy utilizing a codon-optimized GM-CSF gene overcomes the limitation and improves the efficacy of tumor cell-based vaccines.     

In vitro evidence that commercial influenza vaccines are not similar in their ability to activate human T cell responses

We evaluated three commercial trivalent inactivated vaccines (TIVs) from the 2007-2008 season in terms of their ability to elicit in vitro T cell responses. T cell-mediated immunity may offer a more cross-reactive vaccine approach for the prevention of pandemic or epidemic influenza. Human cytotoxic T cell lines demonstrated differences in matrix protein 1 and nucleocapsid protein recognition of autologous target cells. Peripheral blood mononuclear cells stimulated with each of the TIVs showed statistically significant differences between the vaccines in the numbers of IFNgamma producing cells activated. These data suggest that TIV vaccines are not similar in their ability to activate human T cell responses.     

The art of partnerships for vaccines

The Developing Countries Vaccine Manufacturers Network (DCVMN) convened vaccine manufacturing experts and leaders from local and global public health organizations for its 19th Annual General Meeting. Lectures and panel discussions centered on international cooperation for better access to vaccines, and partnerships in areas ranging from vaccine research and process development, to clinical studies, regulatory, supply chain and emergency preparedness and response.Global vaccine market trends and changes that will impact vaccine financing and procurement methods were discussed as well as capital sources, including funding, for the development of new or improved vaccines.DCVMN members presented their progress in developing novel Hexavalent, Meningitis, Pneumococcal Conjugate Vaccine, Shigella, Mumps, Rotavirus, Yellow Fever, Polio, Hepatitis E and Dengue vaccines, and a novel monoclonal antibody cocktail for post-bite prophylaxis against rabies infections.Access to and availability of vaccines is enhanced through sharing of best practices for vaccine quality control, reducing redundant testing and promoting development of harmonized common standards. Eligible stakeholders were encouraged to join the WHO-National Control Laboratory Network for Biologicals which serves as a platform for collaboration and technical exchange in this area.Increasing regulatory convergence at the regional and global levels through mechanisms such as joint dossier review and the WHO Collaborative Registration Procedure can help to accelerate vaccine access globally. Additionally, four proposals for streamlining procedures and alignment of dossiers were discussed.Successful partnerships between a broad range of stakeholders, including international organizations, manufacturers, academic research institutes and regulators have provided support for, and in some cases accelerated, vaccine innovation, clinical trials and registration, WHO prequalification, vaccine introduction and access. Strong partnerships, based on experience and trust, help leverage opportunities and are critically important to advancing the shared goal of providing quality vaccines for all people.     

Evaluation of murine bone marrow-derived dendritic cells loaded with inactivated virus as a vaccine against Japanese encephalitis virus

Japanese encephalitis (JE) is a serious infectious disease in southern and eastern Asia. Design and development of safer and more efficacious vaccines against Japanese encephalitis virus (JEV) is a high-priority target in the world. Dendritic cells (DCs) are the most potent professional antigen-presenting cells (APCs) playing a central and unique role in the generation of primary T-cell responses, and are considered attractive “live adjuvants” for vaccination and immunotherapy against cancer and infectious diseases. In this study, mouse bone marrow-derived dendritic cells (bmDCs were generated and stimulated with inactivated JEV in vitro. BALB/c mice were immunized with stimulated bmDCs and then challenged with JEV wild-type strain. The neutralization antibody, interferon gamma (IFN-γ), tumor necrosis factors alpha (TNF-α) or interleukin-6 (IL-6), and virus-specific CD8+ cytotoxic T-lymphocyte (CTL) levels, as well as survival rates, were analyzed and compared with inactivated vaccine and DCs control groups. The results demonstrated that intravenous (i.v.) injection of 2 × 10⁵ JEV-pulsed bmDCs into each mouse produced notable levels of JEV-specific neutralizing antibodies and higher levels of CD8+ CTL, IFN-γ and TNF-α compared with JEV-inactivated vaccine. Furthermore, stimulated bmDCs could elicit a highly protective efficacy (90%) against JEV challenge. It suggests that stimulated bmDCs can be considered as an attractive “live adjuvant” for vaccination against JEV infection.     

A bibliometric analysis of systematic reviews on vaccines and immunisation

IntroductionSYSVAC is an online bibliographic database of systematic reviews and systematic review protocols on vaccines and immunisation compiled by the London School of Hygiene & Tropical Medicine and hosted by the World Health Organization (WHO) through their National Immunization Technical Advisory Groups (NITAG) resource centre (www.nitag-resource.org). Here the development of the database and a bibliometric review of its content is presented, describing trends in the publication of policy-relevant systematic reviews on vaccines and immunisation from 2008 to 2016.Materials and methodsSearches were conducted in seven scientific databases according to a standardized search protocol, initially in 2014 with the most recent update in January 2017. Abstracts and titles were screened according to specific inclusion criteria. All included publications were coded into relevant categories based on a standardized protocol and subsequently analysed to look at trends in time, topic, area of focus, population and geographic location.ResultsAfter screening for inclusion criteria, 1285 systematic reviews were included in the database. While in 2008 there were only 34 systematic reviews on a vaccine-related topic, this increased to 322 in 2016. The most frequent pathogens/diseases studied were influenza, human papillomavirus and pneumococcus. There were several areas of duplication and overlap.DiscussionAs more systematic reviews are published it becomes increasingly time-consuming for decision-makers to identify relevant information among the ever-increasing volume available. The risk of duplication also increases, particularly given the current lack of coordination of systematic reviews on vaccine-related questions, both in terms of their commissioning and their execution. The SYSVAC database offers an accessible catalogue of vaccine-relevant systematic reviews with, where possible access or a link to the full-text.ConclusionsSYSVAC provides a freely searchable platform to identify existing vaccine-policy-relevant systematic reviews. Systematic reviews will need to be assessed adequately for each specific question and quality.     

Typhoid vaccines: WHO position paper,March 2018 – Recommendations

This article presented the World Health Organization’s (WHO) recommendations on the use of Typhoid vaccines excerpted from the Typhoid vaccines: WHO position paper – March 2018 published in the Weekly Epidemiological Record (World Health Organization, 2018) [1]. This position paper replaces the 2008 WHO position paper on typhoid vaccines (WHO, 2008) [2]. It re-emphasizes the importance of vaccination to control typhoid fever and presents the WHO recommendations on the use of a new generation of typhoid conjugate vaccines.Footnotes to this paper provide a number of core references including references to grading tables that assess the quality of the scientific evidence, and to the evidence-to-recommendation tables. In accordance with its mandate to provide guidance to Member States on health policy matters, WHO issues a series of regularly updated position papers on vaccines and combinations of vaccines against diseases that have an international public health impact. These papers are concerned primarily with the use of vaccines in large-scale immunization programmes; they summarize essential background information on diseases and vaccines, and conclude with WHO’s current position on the use of vaccines in the global context. Recommendations on the use of cholera vaccines were discussed by the Strategic Advisory Group of Experts (SAGE) in October 2017; evidence presented at these meetings can be accessed at: http://www.who.int/immunization/sage/meetings/2017/October/presentations_background_docs/en/.     

树突状细胞活化的CTLs联合5-FU在裸鼠体内外对子宫颈癌的抑制作用

目的:探讨树突状细胞(DCs)活化的细胞毒T细胞(CTLs)联合5-氟尿嘧啶(5-FU)在裸鼠体内外对子宫颈癌的抑制作用。方法:MTT法检测DCs激活的CTLs联合5-FU在裸鼠体外对子宫颈癌细胞的抑制作用。裸鼠体内实验分为CTLs治疗组、5-FU治疗组、CTLs/5-FU治疗组及对照组,观察移植瘤成瘤率、潜伏期、瘤重及瘤体积。结果:治疗组在裸鼠体外都显著抑制子宫颈癌细胞生长,CTLs/5-FU治疗组最显著(P<0.01)。裸鼠体内实验中,治疗组的成瘤率、瘤体积、瘤重都显著降低,潜伏期延长,CTLs/5-FU治疗组最显著(P<0.01)。结论:联合应用DCs激活的CTLs及5-FU比单独应用CTLs或5-FU更有效。     

Targeting dendritic cells in humanized mice receiving adoptive T cells via monoclonal antibodies fused to Flu epitopes

The targeting of vaccine antigens to antigen presenting cells (APC), such as dendritic cells (DCs), is a promising strategy for boosting vaccine immunogenicity and, in turn, protective and/or therapeutic efficacy. However, in vivo systems are needed to evaluate the potential of this approach for testing human vaccines. To this end, we examined human CD8⁺ T-cell expansion to novel DC-targeting vaccines in vitro and in vivo in humanized mice. Vaccines incorporating the influenza matrix protein-1 (FluM1) antigen fused to human specific antibodies targeting different DC receptors, including DEC-205, DCIR, Dectin-1, and CD40, elicited human CD8⁺ T-cell responses, as defined by the magnitude of specific CD8⁺ T-cells to the targeted antigen. In vitro we observed differences in response to the different vaccines, particularly between the weakly immunogenic DEC-205-targeted and more strongly immunogenic CD40-targeted vaccines, consistent with previous studies. However, in humanized mice adoptively transferred (AT) with mature human T cells (HM-T), vaccines that performed weakly in vitro (i.e., DEC-205, DCIR, and Dectin-1) gave stronger responses in vivo, some resembling those of the strongly immunogenic CD40-targeted vaccine. These results demonstrate the utility of the humanized mouse model as a platform for studies of human vaccines.     

宫颈癌细胞冻融抗原负载树突状细胞激发细胞毒性T淋巴细胞杀伤宫颈癌细胞的体外研究

目的研究HeLa、SiHa两种宫颈癌细胞株冻融抗原负载的树突状细胞(dendritic cells,DC)诱导细胞毒性T淋巴细胞(CTL)体外抗原特异性杀伤官颈癌细胞的能力.方法利用免疫磁珠分离法(MACS)分离纯化脐血CD34 细胞并在体外诱导分化为DC,用反复冻融法分别从两种宫颈癌细胞株(HeLa利SiHa)中提取可溶性冻融抗原并负载DC.流式细胞学检测负载两种抗原后DC表面分子的表达,ELISA法检测DC上清中IL-12的表达,MLR测定DC刺激T细胞增殖的能力,MTT法检测DC经抗原负载后激活的CTL分别对HeLa和SiHa细胞的杀伤作用.结果与未经抗原负载的DC相比,经HeLa和SiHa冻融抗原负载的DC能更好的表达各种DC分化相关抗原(CD1a、CD83、CD80、HLA-DR以及CD54),刺激T淋巴细胞增殖和IL-12分泌的能力也显著加强(P＜0.05).与未经抗原负载相比,两种宫颈癌细胞冻融抗原负载DC后激发的CTL在体外对官颈癌细胞的杀伤能力也明显加强.此外,HeLa细胞抗原负载DC诱导的CTL在体外对HeLa细胞的杀伤率为72.2%,显著高于它对SiHa细胞的杀伤率(22.3%);而SiHa细胞抗原负载DC诱导的CTL对SiHa细胞的杀伤率为69.5%,也明显高于它对HeLa细胞的杀伤率(28.1%),具有显著的抗原特异性.结论经宫颈癌细胞冻融抗原负载DC激活的CTL在体外具有更强的增殖能力,并具有抗原特异性杀伤宫颈癌细胞的作用.     

Identifying protective dengue vaccines: Guide to mastering an empirical process

A recent clinical trial of a live-attenuated tetravalent chimeric yellow fever-dengue vaccine afforded no protection against disease caused by dengue 2 (DENV-2). This outcome was unexpected as two or more doses of this vaccine had raised broad neutralizing antibody responses. Data from pre-clinical subhuman primate studies revealed that vaccination with the monotypic DENV-2 component failed to meet established criteria for solid protection to homotypic live virus challenge. Accordingly, it is suggested that preclinical testing adopt more rigorous criteria for protection and that Phase I testing be extended to require evidence of solid monotypic protective immunity for each component of a dengue vaccine by direct challenge with live-attenuated DENV. Because live-attenuated tetravalent DENV vaccines exhibit evidence of immunological interference phenomena, during Phase II, volunteers given mixtures of DENV 1–4 vaccines should be separately challenged with monotypic live-attenuated DENV. Immune responses to live-attenuated challenge viruses and vaccine strains should be studied in an attempt to develop useful in vitro correlates of in vivo protection. Finally, it will be important to learn if DENV non-structural protein 1 (NS1) contributes to pathogenesis of the vascular permeability syndrome in humans. If so, immunity to dengue 1–4 NS1 may be crucial to prevent severe disease.     

Improving access to affordable vaccines for middle-income countries in the african region

Despite the remarkable power of immunization reducing morbidity and mortality due to vaccine preventable diseases, one in five African children still does not receive all the basic, necessary vaccines. This is particularly true of the 10 middle-income countries (MICs) in the WHO African Region, where data demonstrates that immunization coverage is decreasing. These countries are not eligible for Gavi support in accessing new vaccines because of their relatively high per capita income level and will gradually increase with the transitioning of countries out of Gavi support. Thus, WHO was requested to facilitate access to affordable vaccines in relation to middle-income countries and those transitioning out of Gavi support in the near future. With commitment to address the issue, WHO Regional Office for Africa convened a consultative meeting from 09 to 11 April 2018 in Brazzaville, Congo to explore ways of improving access to affordable vaccines for MICs in the Region. The meeting brought together 17 low, middle and upper middle income countries in the African Region. Immunization partners and other WHO Regions also participated in the consultation to share experiences and explore ways of increasing access to affordable vaccines in MICs in the African Region. At the end of the meeting a number of solutions and action points were proposed for implementation in the Region.     

Cytotoxic T cell polyepitope vaccines delivered by ISCOMs

CD8 β cytotoxic T lymphocyte (CTL) polyepitope or polytope vaccines have traditionally been delivered using recombinant vector or DNA based delivery modalities. Here we show the delivery of polytope vaccines in the form of either synthetic polypeptides or recombinant polytope proteins by ImmunoStimulatory COMplexes (ISCOMs®). Induction of multiple protective CTL responses by these polytope-ISCOM formulations were comparable to viral vector or DNA based delivery modalities as assessed by IFNγ ELISpot, chromium release and viral challenge assays. Measurement of CTL responses specific for the different epitopes revealed immunodominance patterns, which were largely independent of the vaccine vector or the order of the epitopes in the polytope. ISCOMs thus emerge as a viable human delivery modality for protein-based polytope vaccines.     

中国3个地区儿童家长对国家免疫规划类疫苗犹豫现状研究

目的:了解我国儿童家长对国家免疫规划类疫苗犹豫发生率和影响因素,并探索不同种类疫苗的犹豫现状。方法:在北京市通州区、四川省成都市及甘肃省白银市进行横断面调查,采用成比例概率抽样和便利抽样的方法选取符合标准的研究对象进行问卷调查。结果:共纳入研究对象3 592人,38.22%的家长完全接受所有疫苗,59.35%的家长给儿...     

Vaccine wastage in Ghana,Mozambique, and Pakistan: An assessment of wastage rates for four vaccines and the context,causes, drivers,and knowledge,attitudes and practices for vaccine wastage

Vaccine procurement costs comprise a significant share of immunization program costs in low- and middle-income countries, yet not all procured vaccines are administered. Vaccine wastage occurs due to vial breakage, excessive heat or freezing, expiration, or when not all doses in a multidose vial are used. Better estimates of vaccine wastage rates and their causes could support improved management of vaccine stocks and reduce procurement costs. This study examined aspects of wastage for four vaccines at service delivery points in Ghana (n = 48), Mozambique (n = 36), and Pakistan (n = 46). We used prospective data from daily and monthly vaccine usage data entry forms, along with cross-sectional surveys, and in-depth interviews. The analysis found that estimated monthly proportional open-vial wastage rates for vaccines in single-dose vials (SDV) or in multi-dose vials (MDV) that can be kept refrigerated up to four weeks after opening ranged from 0.08 % to 3 %. For MDV where remaining doses are discarded within six hours after opening, the mean wastage rates ranged from 5 % to 33 %, with rates being highest for measles containing vaccine. Despite national-level guidance to open a vaccine vial even when only one child is present, vaccines in MDV that are discarded within six hours of opening are sometimes offered less frequently than vaccines in SDV or in MDV where remaining doses can be used for up to 4 weeks. This practice can lead to missed opportunities for vaccination. While closed-vial wastage at service delivery points (SDPs) was relatively rare, individual instances can result in large losses, suggesting that monitoring closed-vial wastage should not be neglected. Health workers reported insufficient knowledge of vaccine wastage tracking and reporting methods. Improving reporting forms would facilitate more accurate reporting of all causes of wastage, as would additional training and supportive supervision. Globally, decreasing doses per vial could reduce open-vial wastage.     

Effective CD8 T cell priming and tumor protection by enterotoxin B subunit-conjugated peptides targeted to dendritic cells

In our previous studies we have shown that bacterial enterotoxin B subunits are effective vehicles to deliver antigen into the MHC class I processing route. Here we have used the non-toxic Escherichia coli heat labile enterotoxin B subunit (EtxB) conjugated to OVA peptide (EtxB–peptide) to address the impact on induction of specific CD8⁺ T cells in vivo. Although incubation of DCs with these EtxB–peptide conjugates as such did not induce DC maturation in vitro MHC class I antigen presentation was much more efficient as compared to peptide alone. Antigen presentation was further enhanced upon DC maturation with the TLR-4 ligand LPS. Injection of matured DCs incubated with EtxB–peptide conjugates lead to strong induction of OVA-specific CD8⁺ T lymphocytes and fully prevented the outgrowth of lethal B16 melanoma in wild type mice. Our data demonstrate that bacterial non-toxic B subunit–peptide conjugates are potent vaccine vehicles for induction of protective CD8⁺ T cell responses.     

Low antigen dose formulated in CAF09 adjuvant Favours a cytotoxic T-cell response following intraperitoneal immunization in Göttingen minipigs

The relationship between the antigen dose and the quality of an immune response generated upon immunization is poorly understood. However, findings show that the immune system is indeed influenced by the antigen dose; hence underlining the importance of correctly determining which dose to use in order to generate a certain type of immune response.To investigate this area further, we used Göttingen minipigs as an animal model especially due to the similar body size and high degree of immunome similarity between humans and pigs. In this study, we show that both a humoral and a cell-mediated immune (CMI) response can be generated following intraperitoneal immunization with tetanus toxoid (TT) formulated in the CAF09 liposomal adjuvant. Importantly, a low antigen dose induced more TT-specific polyfunctional T cells, whereas antigen-specific IgG production was observed upon high-dose immunization. Independent of antigen dose, intraperitoneal administration of antigen increased the amount of TT-specific cytotoxic CD8β⁺ T cells within the cytokine-producing T-cell pool when compared to the non-cytokine producing T-cell compartment.Taken together, these results demonstrate that a full protein formulated in the CAF09 adjuvant and administered to pigs via the intraperitoneal route effectively generates a cytotoxic T-cell response. Moreover, we confirm the inverse relationship between the antigen dose and the induction of polyfunctional T cells in a large animal model. These finding can have implications for the design of upcoming vaccine trials aiming at establishing a cytotoxic T-cell response.     

Delivery to the lower respiratory tract is required for effective immunization with Newcastle disease virus-vectored vaccines intended for humans

Newcastle disease virus (NDV), an avian virus, is being evaluated for the development of vectored human vaccines against emerging pathogens. Previous studies of NDV-vectored vaccines in a mouse model suggested their potency after delivery by injection or by the intranasal route. We compared the efficacy of various routes of delivery of NDV-vectored vaccines in a non-human primate model. While delivery of an NDV-vectored vaccine by the combined intranasal/intratracheal route elicited protective immune responses, delivery by the subcutaneous route or the intranasal route alone elicited limited or no protective immune responses, suggesting the necessity for vaccine delivery to the lower respiratory tract. Furthermore, direct comparison of a vaccine based on an NDV mesogenic strain (NDV-BC) with a similarly designed NDV vector based on a modified lentogenic strain carrying a polybasic F cleavage site (NDV-VF) suggested that the two NDV strains were similar in immunogenicity and were equally protective.     

Targeting of nucleoprotein to chemokine receptors by DNA vaccination results in increased CD8+-mediated cross protection against influenza

Vaccination is at present the most efficient way of preventing influenza infections. Currently used inactivated influenza vaccines can induce virus-neutralizing antibodies that are protective against a particular influenza strain, but hamper the induction of cross-protective T-cell responses to later infections. Thus, influenza vaccines need to be updated annually in order to confer protection against circulating influenza strains. This study aims at developing an efficient vaccine that can induce broader protection against influenza. For this purpose, we have used the highly conserved nucleoprotein (NP) from an influenza A virus subtype H7N7 strain, and inserted it into a vaccine format that targets an antigen directly to relevant antigen presenting cells (APCs). The vaccine format consists of bivalent antigenic and targeting units, linked via an Ig-based dimerization unit. In this study, NP was linked to MIP-1α, a chemokine that targets the linked antigen to chemokine receptors 1, 3 and 5 expressed on various APCs. The vaccine protein was indirectly delivered by DNA. Mice were vaccinated intradermally with plasmids, in combination with electroporation to enhance cellular uptake of DNA. We found that a single DNA vaccination was sufficient for induction of both antibody and T cell responses in BALB/c mice. Targeting of nucleoprotein to chemokine receptors enhanced T cell responses but not antibody responses. Moreover, a single dose of MIP1α-NP conferred protection in BALB/c mice against a lethal challenge with an H1N1 influenza virus. The observed cross-protection was mediated by CD8⁺ T cells.