-
Drug and Therapeutics Bulletin Oct 2017For many years, the UK seasonal influenza vaccination programme has been offered to people at higher risk from the complications of influenza infection, including those... (Review)
Review
For many years, the UK seasonal influenza vaccination programme has been offered to people at higher risk from the complications of influenza infection, including those aged over 65 years and anyone aged over 6 months who is in a clinical risk group. In 2012, the Joint Committee on Vaccination and Immunisation (JCVI) recommended extending seasonal influenza vaccination to children aged 2-16 years who are not in a clinical risk group. In contrast to the vaccination programme for adults, which uses an injectable inactivated influenza vaccine, children are being offered a live attenuated influenza vaccine (LAIV) that is administered intranasally. Here, we consider the evidence for the use of the intranasal influenza vaccine for children who are not in a clinical risk group.
Topics: Administration, Intranasal; Adolescent; Child; Child Health Services; Child, Preschool; Humans; Immunization Programs; Influenza Vaccines; Influenza, Human; State Medicine; United Kingdom; Vaccines, Attenuated
PubMed: 29021248
DOI: 10.1136/dtb.2017.10.0538 -
Expert Review of Vaccines Sep 2016A novel vaccine platform uses DNA immunization to launch live-attenuated virus vaccines in vivo. This technology has been applied for vaccine development against... (Review)
Review
A novel vaccine platform uses DNA immunization to launch live-attenuated virus vaccines in vivo. This technology has been applied for vaccine development against positive-strand RNA viruses with global public health impact including alphaviruses and flaviviruses. The DNA-launched vaccine represents the recombinant plasmid that encodes the full-length genomic RNA of live-attenuated virus downstream from a eukaryotic promoter. When administered in vivo, the genomic RNA of live-attenuated virus is transcribed. The RNA initiates limited replication of a genetically defined, live-attenuated vaccine virus in the tissues of the vaccine recipient, thereby inducing a protective immune response. This platform combines the strengths of reverse genetics, DNA immunization and the advantages of live-attenuated vaccines, resulting in a reduced chance of genetic reversions, increased safety, and improved immunization. With this vaccine technology, the field of DNA vaccines is expanded from those that express subunit antigens to include a novel type of DNA vaccines that launch live-attenuated viruses.
Topics: Animals; Humans; Plasmids; RNA Virus Infections; RNA Viruses; RNA, Viral; Vaccines, Attenuated; Vaccines, DNA; Viral Vaccines
PubMed: 27055100
DOI: 10.1080/14760584.2016.1175943 -
Vaccine Jul 2016The heterologous or non-specific effects (NSEs) of vaccines, at times defined as "off-target effects" suggest that they can affect the immune response to organisms other...
The heterologous or non-specific effects (NSEs) of vaccines, at times defined as "off-target effects" suggest that they can affect the immune response to organisms other than their pathogen-specific intended purpose. These NSEs have been the subject of clinical, immunological and epidemiological studies and are increasingly recognized as an important biological process by a growing group of immunologists and epidemiologists. Much remain to be learned about the extent and underlying mechanisms for these effects. The conference "Off-target effects of vaccination" held in Annecy-France (June 8-10 2015) intended to take a holistic approach drawing from the fields of immunology, systems biology, epidemiology, bioinformatics, public health and regulatory science to address fundamental questions of immunological mechanisms, as well as translational questions about vaccines NSEs. NSE observations were examined using case-studies on live attenuated vaccines and non-live vaccines followed by discussion of studies of possible biological mechanisms. Some possible pathways forward in the study of vaccines NSE were identified and discussed by the expert group.
Topics: Congresses as Topic; France; Humans; Immunity, Heterologous; Immunity, Innate; Immunologic Memory; Vaccines, Attenuated; Vaccines, Inactivated
PubMed: 27312214
DOI: 10.1016/j.vaccine.2016.06.020 -
Pathogens and Global Health Jun 2015During the last decade, the chikungunya (CHIKV) virus has expanded its range of activity, conquering new territories and becoming an important global health threat. In... (Review)
Review
During the last decade, the chikungunya (CHIKV) virus has expanded its range of activity, conquering new territories and becoming an important global health threat. In particular, the challenge represented by the recent emergence of CHIKV in the Americas has strengthened the need of a safe and effective vaccine. Although research on vaccines against CHIKV has been slow, a few vaccine candidates have been tested over the years. Inactivated and attenuated vaccine candidates have shown promising results in phase I/II trials, and engineered vaccines have proven to be safe and immunogenic in mouse and/or non-human primate models. Recently, a vaccine based on virus-like particles (VLP) has been successfully tested in a phase I trial. However, large phase I/II controlled trials, which are needed in order to provide evidence of vaccine efficacy, may be planned only under certain conditions. First, they should be conducted during epidemic periods, when a large number of cases occur, in order to ensure an adequate study power. Second, they are expensive and investments returns are not always guaranteed. To overcome this problem, public/private partnership and government support, the identification of target population groups for vaccination and the commitment of donor agencies are key factors for supporting both the development and the availability of vaccines against neglected tropical diseases like chikungunya.
Topics: Animals; Antibodies, Neutralizing; Antibodies, Viral; Chikungunya Fever; Chikungunya virus; Clinical Trials as Topic; Disease Models, Animal; Disease Outbreaks; Financing, Government; Global Health; Humans; Mice; Public-Private Sector Partnerships; Vaccination; Vaccines, Attenuated
PubMed: 25971340
DOI: 10.1179/2047773215Y.0000000017 -
European Journal of Pharmaceutics and... Jan 2018Vaccination represents a cost-effective weapon for disease prevention and has proven to dramatically reduce the incidences of several diseases that once were responsible... (Review)
Review
Vaccination represents a cost-effective weapon for disease prevention and has proven to dramatically reduce the incidences of several diseases that once were responsible for significant mortality and morbidity worldwide. The nasal cavity constitutes the initial stage of the respiratory system and the first contact with inhaled pathogens. The intranasal (IN) route for vaccine administration is an attractive alternative to injection, due to the ease of administration as well as better patient compliance. Many published studies have demonstrated the safety and effectiveness of IN immunization with liquid vaccines. Currently, two liquid IN vaccines are available and both contain live attenuated influenza viruses. FluMist® was approved in 2003 in the United States, and Nasovac® H1N1 vaccine was approved in India in 2010. Preclinical studies showed that IN immunization with dry powder vaccines (DPVs) is feasible. Although there is not a commercially available DPV yet, DPVs have the inherent advantage of being relatively more stable than liquid vaccines. This review focuses on recent developments of DPVs as next-generation IN vaccines.
Topics: Administration, Intranasal; Animals; Humans; Immunization; Nasal Cavity; Powders; Vaccination; Vaccines, Attenuated
PubMed: 29122735
DOI: 10.1016/j.ejpb.2017.11.001 -
Viral Immunology Mar 2018Varicella zoster virus (VZV) is the cause of chickenpox (varicella) and shingles (zoster), and was once responsible for over 4 million infections in the United States... (Review)
Review
Varicella zoster virus (VZV) is the cause of chickenpox (varicella) and shingles (zoster), and was once responsible for over 4 million infections in the United States annually. The development of a live attenuated VZV vaccine was initially viewed with extreme skepticism. Nonetheless, a VZV vaccine was developed in the 1970s by Takahashi and his colleagues in Japan and was eventually licensed in the US. It is now known to be one of the safest and most effective vaccines available and is administered worldwide. Here are described important factors that contributed to the successful research and licensure of the highly successful VZV vaccine.
Topics: Chickenpox; Chickenpox Vaccine; Drug Approval; Herpes Zoster; Herpes Zoster Vaccine; Herpesvirus 3, Human; Humans; United States; Vaccines, Attenuated
PubMed: 29173081
DOI: 10.1089/vim.2017.0136 -
Vaccine Sep 2021In an effort to control the COVID-19 pandemic, large-scale vaccination is being implemented in various countries using anti-SARS-CoV-2 vaccines based on mRNAs,... (Review)
Review
In an effort to control the COVID-19 pandemic, large-scale vaccination is being implemented in various countries using anti-SARS-CoV-2 vaccines based on mRNAs, adenovirus vectors, and inactivated viruses. However, there are concerns regarding adverse effects, such as the induction of fever attributed to mRNA vaccines and pre-existing immunity against adenovirus vectored vaccines or their possible involvement in the development of thrombosis. The induction of antibodies against the adenovirus vector itself constitutes another hindrance, rendering boosting vaccinations ineffective. Additionally, it has been questioned whether inactivated vaccines that predominantly induce humoral immunity are effective against newly arising variants, as some isolated strains were found to be resistant to the serum from COVID-19-recovered patients. Although the number of vaccinated people is steadily increasing on a global scale, it is still necessary to develop vaccines to address the difficulties and concerns mentioned above. Among the various vaccine modalities, live attenuated vaccines have been considered the most effective, since they closely replicate a natural infection without the burden of the disease. In our attempt to provide an additional option to the repertoire of COVID-19 vaccines, we succeeded in isolating temperature-sensitive strains with unique phenotypes that could serve as seeds for a live attenuated vaccine. In this review article, we summarize the characteristics of the currently approved SARS-CoV-2 vaccines and discuss their advantages and disadvantages. In particular, we focus on the novel temperature-sensitive variants of SARS-CoV-2 that we have recently isolated, and their potential application as live-attenuated vaccines. Based on a thorough evaluation of the different vaccine modalities, we argue that it is important to optimize usage not only based on efficacy, but also on the phases of the pandemic. Our findings can be used to inform vaccination practices and improve global recovery from the COVID-19 pandemic.
Topics: COVID-19; COVID-19 Vaccines; Humans; Pandemics; SARS-CoV-2; Vaccines, Attenuated
PubMed: 34426024
DOI: 10.1016/j.vaccine.2021.08.018 -
Human Vaccines & Immunotherapeutics Dec 2022Despite the existence of a highly efficient yellow fever vaccine, yellow fever reemergence throughout Africa and the Americas has put 900 million people in 47 countries... (Review)
Review
Despite the existence of a highly efficient yellow fever vaccine, yellow fever reemergence throughout Africa and the Americas has put 900 million people in 47 countries at risk of contracting the disease. Although the vaccine has been key to controlling yellow fever epidemics, its live-attenuated nature comes with a range of contraindications that prompts advising against its administration to pregnant and lactating women, immunocompromised individuals, and those with hypersensitivity to chicken egg proteins. Additionally, large outbreaks have highlighted problems with insufficient vaccine supply, whereby manufacturers rely on slow traditional manufacturing processes that prevent them from ramping up production. These limitations have contributed to an inadequate control of yellow fever and have favored the pursuit of novel yellow fever vaccine candidates that aim to circumvent the licensed vaccine's restrictions. Here, we review the live-attenuated vaccine's limitations and explore the epitome of a yellow fever vaccine, whilst scrutinizing next-generation vaccine candidates.
Topics: Disease Outbreaks; Female; Humans; Lactation; Vaccines, Attenuated; Yellow Fever; Yellow Fever Vaccine; Yellow fever virus
PubMed: 33974507
DOI: 10.1080/21645515.2021.1895644 -
Expert Review of Vaccines 2015Evidence of high efficacy of live attenuated influenza vaccine (LAIV) from randomized controlled trials is strong for children 2-6 years of age, but fewer data exist for... (Review)
Review
Evidence of high efficacy of live attenuated influenza vaccine (LAIV) from randomized controlled trials is strong for children 2-6 years of age, but fewer data exist for older school-age children. We reviewed the published data on efficacy and effectiveness of LAIV in children ≥5 years. QUOSA (Elsevier database) was searched for articles published from January 1990 to June 2014 that included 'FluMist', 'LAIV', 'CAIV', 'cold adapted influenza vaccine', 'live attenuated influenza vaccine', 'live attenuated cold adapted' or 'flu mist'. Studies evaluated included randomized controlled trials, effectiveness and indirect protection studies. This review demonstrates that LAIV has considerable efficacy and effectiveness in school-age children.
Topics: Administration, Intranasal; Adolescent; Child; Child, Preschool; Databases, Factual; Humans; Influenza A virus; Influenza B virus; Influenza Vaccines; Influenza, Human; Schools; Vaccination; Vaccines, Attenuated
PubMed: 26372891
DOI: 10.1586/14760584.2015.1078732 -
Human Vaccines & Immunotherapeutics Mar 2018The safety of vaccines is a critical factor in maintaining public trust in national vaccination programs. Vaccines are recommended for children, adults and elderly... (Review)
Review
The safety of vaccines is a critical factor in maintaining public trust in national vaccination programs. Vaccines are recommended for children, adults and elderly subjects and have to meet higher safety standards, since they are administered to healthy subjects, mainly healthy children. Although vaccines are strictly monitored before authorization, the possibility of adverse events and/or rare adverse events cannot be totally eliminated. Two main types of influenza vaccines are currently available: parenteral inactivated influenza vaccines and intranasal live attenuated vaccines. Both display a good safety profile in adults and children. However, they can cause adverse events and/or rare adverse events, some of which are more prevalent in children, while others with a higher prevalence in adults. The aim of this review is to provide an overview of influenza vaccine safety according to target groups, vaccine types and production methods.
Topics: Humans; Influenza Vaccines; Influenza, Human; Vaccines, Attenuated; Vaccines, Inactivated
PubMed: 29297746
DOI: 10.1080/21645515.2017.1423153