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Viruses Apr 2022African swine fever (ASF) is causing a pandemic affecting swine in a large geographical area of the Eastern Hemisphere, from Central Europe to East and Southeast Asia,... (Review)
Review
African swine fever (ASF) is causing a pandemic affecting swine in a large geographical area of the Eastern Hemisphere, from Central Europe to East and Southeast Asia, and recently in the Americas, the Dominican Republic and Haiti. The etiological agent, ASF virus (ASFV), infects both domestic and wild swine and produces a variety of clinical presentations depending on the virus strain and the genetics of the pigs infected. No commercial vaccines are currently available, although experimental recombinant live attenuated vaccine candidates have been shown to be efficacious in protecting animals against disease when challenged with homologous virulent strains. This review attempts to systematically provide an overview of all the live attenuated strains that have been shown to be experimental vaccine candidates. Moreover, it aims to analyze the development of these vaccine candidates, obtained by deleting specific genes or group of genes, and their efficacy in preventing virus infection and clinical disease after being challenged with virulent isolates. This report summarizes all the experimental vaccine strains that have shown promise against the contemporary pandemic strain of African swine fever.
Topics: African Swine Fever; African Swine Fever Virus; Animals; Swine; Vaccines, Attenuated; Vaccines, Synthetic; Viral Vaccines; Viruses, Unclassified
PubMed: 35632620
DOI: 10.3390/v14050878 -
Nature Jul 2023Vaccination with Sabin, a live attenuated oral polio vaccine (OPV), results in robust intestinal and humoral immunity and has been key to controlling poliomyelitis. As...
Vaccination with Sabin, a live attenuated oral polio vaccine (OPV), results in robust intestinal and humoral immunity and has been key to controlling poliomyelitis. As with any RNA virus, OPV evolves rapidly to lose attenuating determinants critical to the reacquisition of virulence resulting in vaccine-derived, virulent poliovirus variants. Circulation of these variants within underimmunized populations leads to further evolution of circulating, vaccine-derived poliovirus with higher transmission capacity, representing a significant risk of polio re-emergence. A new type 2 OPV (nOPV2), with promising clinical data on genetic stability and immunogenicity, recently received authorization from the World Health Organization for use in response to circulating, vaccine-derived poliovirus outbreaks. Here we report the development of two additional live attenuated vaccine candidates against type 1 and 3 polioviruses. The candidates were generated by replacing the capsid coding region of nOPV2 with that from Sabin 1 or 3. These chimeric viruses show growth phenotypes similar to nOPV2 and immunogenicity comparable to their parental Sabin strains, but are more attenuated. Our experiments in mice and deep sequencing analysis confirmed that the candidates remain attenuated and preserve all the documented nOPV2 characteristics concerning genetic stability following accelerated virus evolution. Importantly, these vaccine candidates are highly immunogenic in mice as monovalent and multivalent formulations and may contribute to poliovirus eradication.
Topics: Animals; Mice; Disease Models, Animal; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Oral; Vaccines, Attenuated; Disease Eradication
PubMed: 37316671
DOI: 10.1038/s41586-023-06212-3 -
The Lancet. Infectious Diseases Jan 2018Conflicting reports have emerged about the effectiveness of the live attenuated influenza vaccine. The live attenuated influenza vaccine appears to protect particularly... (Review)
Review
Conflicting reports have emerged about the effectiveness of the live attenuated influenza vaccine. The live attenuated influenza vaccine appears to protect particularly poorly against currently circulating H1N1 viruses that are derived from the 2009 pandemic H1N1 viruses. During the 2015-16 influenza season, when pandemic H1N1 was the predominant virus, studies from the USA reported a complete lack of effectiveness of the live vaccine in children. This finding led to a crucial decision in the USA to recommend that the live vaccine not be used in 2016-17 and to switch to the inactivated influenza vaccine. Other countries, including the UK, Canada, and Finland, however, have continued to recommend the use of the live vaccine. This policy divergence and uncertainty has far reaching implications for the entire global community, given the importance of the production capabilities of the live attenuated influenza vaccine for pandemic preparedness. In this Personal View, we discuss possible explanations for the observed reduced effectiveness of the live attenuated influenza vaccine and highlight the underpinning scientific questions. Further research to understand the reasons for these observations is essential to enable informed public health policy and commercial decisions about vaccine production and development in coming years.
Topics: Global Health; Health Policy; Humans; Influenza Vaccines; Influenza, Human; Orthomyxoviridae; Treatment Outcome; Vaccines, Attenuated
PubMed: 28780285
DOI: 10.1016/S1473-3099(17)30360-2 -
Infectious Diseases of Poverty Dec 2021African swine fever (ASF) is a fatal hemorrhagic disease in domestic pigs and wild boar caused by African swine fever virus (ASFV). Since ASF has been introduced into...
BACKGROUND
African swine fever (ASF) is a fatal hemorrhagic disease in domestic pigs and wild boar caused by African swine fever virus (ASFV). Since ASF has been introduced into Europe and Asia, the major pig-raising areas, posing a huge threat to the pork industry worldwide. Currently, prevention and control of ASF are basically dependent on strict biosecurity measures and stamping-out policy once ASF occurs.
MAIN TEXT
The major risks of ASF spread are insufficient biosecurity measures and human behaviors. Therefore, a safe and effective vaccine seems to be a reasonable demand for the prevention and control of ASF. Due to the efficacy advantage over other types of vaccines, live attenuated vaccines (LAVs), especially virulence-associated genes deleted vaccines, are likely to be put into emergency and conditional use in restricted areas if ASF is out of control in a country with a huge pig population and pork consumption, like China. However, the safety, efficacy, and genetic stability of current candidate ASF LAVs require comprehensive clinical evaluations prior to country-wide field application. Several critical issues need to be addressed to commercialize an ideal ASF LAV, including a stable cell line for manufacturing vaccines, differentiation of infected from vaccinated animals (DIVA), and cross-protection from different genotypes.
CONCLUSION
A safe and effective DIVA vaccine and an accompanying diagnostic assay will facilitate the prevention, control, and eradication of ASF, which is quite challenging in the near future.
Topics: African Swine Fever; African Swine Fever Virus; Animals; Biosecurity; Sus scrofa; Swine; Vaccines, Attenuated; Viral Vaccines
PubMed: 34949228
DOI: 10.1186/s40249-021-00920-6 -
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 -
Microbiology Spectrum Feb 2022Hepatitis-hydropericardium syndrome (HHS) caused by the highly pathogenic fowl adenovirus serotype 4 (FAdV-4) has resulted in huge economic losses to the poultry...
Hepatitis-hydropericardium syndrome (HHS) caused by the highly pathogenic fowl adenovirus serotype 4 (FAdV-4) has resulted in huge economic losses to the poultry industry globally. The gene, as a major virulence determiner, is also an important vaccine target against FAdV-4. In this study, we used a CRISPR/Cas9-based homology-dependent recombinant technique to replace the gene with and generate a novel recombinant virus, designated FAdV4-EGFP-rF2. Although FAdV4-EGFP-rF2 showed low replication ability compared to the wild-type FAdV-4 in LMH cells, FAdV4-EGFP-rF2 could effectively replicate in LMH-F2 cells with the expression of Fiber-2. Moreover, FAdV4-EGFP-rF2 was not only highly attenuated in chickens, but also could provide efficient protection against a lethal challenge of FAdV-4. Moreover, FAdV4-EGFP-rF2 without could induce neutralizing antibodies at the same level as FA4-EGFP with . These results clearly demonstrate that although affects the viral replication and pathogenesis of FAdV-4, it is not necessary for virus replication and induction of neutralizing antibodies; these findings provide novel insights into the roles of and highlight as an insertion site for generating live-attenuated FAdV-4 vaccines against FAdV-4 and other pathogens. Among all serotypes of fowl adenovirus, serotypes FAdV-1, FAdV-4, and FAdV-10 are unique members with two genes ( and ). Recent studies reveal that Fiber-1, not Fiber-2, directly triggers viral infection of FAdV-4, whereas Fiber-2, but not Fiber-1, has been identified as the major virulence determiner and an efficient protective immunogen for subunit vaccines. Here, we replaced with to generate a novel recombinant virus, designated FAdV4-EGFP-rF2. and studies on FAdV4-EGFP-rF2 revealed that was not necessary for either virus replication or efficient protection for FAdV-4; these results not only provide a novel live-attenuated vaccine candidate against HHS, but also give new ideas for generating a FAdV-4 based vaccine vector against other pathogens.
Topics: Adenoviridae Infections; Animals; Antibodies, Neutralizing; Antibodies, Viral; Aviadenovirus; Chickens; Poultry Diseases; Vaccines, Attenuated; Viral Proteins; Viral Vaccines
PubMed: 35107364
DOI: 10.1128/spectrum.01436-21 -
Frontiers in Immunology 2024Dengue, caused by the dengue virus (DENV), affects millions of people worldwide every year. This virus has two distinct life cycles, one in the human and another in the... (Review)
Review
Dengue, caused by the dengue virus (DENV), affects millions of people worldwide every year. This virus has two distinct life cycles, one in the human and another in the mosquito, and both cycles are crucial to be controlled. To control the vector of DENV, the mosquito , scientists employed many techniques, which were later proved ineffective and harmful in many ways. Consequently, the attention shifted to the development of a vaccine; researchers have targeted the E protein, a surface protein of the virus and the NS1 protein, an extracellular protein. There are several types of vaccines developed so far, such as live attenuated vaccines, recombinant subunit vaccines, inactivated virus vaccines, viral vectored vaccines, DNA vaccines, and mRNA vaccines. Along with these, scientists are exploring new strategies of developing improved version of the vaccine by employing recombinant DNA plasmid against NS1 and also aiming to prevent the infection by blocking the DENV life cycle inside the mosquitoes. Here, we discussed the aspects of research in the field of vaccines until now and identified some prospects for future vaccine developments.
Topics: Animals; Humans; Dengue; Dengue Virus; Dengue Vaccines; Mosquito Vectors; Vaccines, Attenuated; Vaccines, Inactivated; Vaccines, DNA; Viral Vaccines
PubMed: 38487527
DOI: 10.3389/fimmu.2024.1362780 -
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 -
Human Vaccines & Immunotherapeutics Dec 2016Changing epidemiology of Hepatitis A virus (HAV) has led to an increased susceptibility of adolescents and adults to the infection. Vaccination can remarkably reduce the... (Review)
Review
Changing epidemiology of Hepatitis A virus (HAV) has led to an increased susceptibility of adolescents and adults to the infection. Vaccination can remarkably reduce the incidence and associated morbidity of HAV infection. This review is focused on the safety and efficacy of H2 strain derived live attenuated Hepatitis A vaccine. We found the vaccine to be highly immunogenic with minimal or negligible safety issues. Moreover, a single dose of live attenuated vaccine persists a long term immune response and can be a preferred option for developing countries. In 2014, Indian Academy of Paediatrics (IAP) also updated their recommendations for H2 vaccine as a single dose as against the previous 2 dose schedule. A focused approach to include the vaccine in national immunization program should be explored.
Topics: Child; Child, Preschool; Hepatitis A; Hepatitis A Vaccines; Humans; India; Vaccines, Attenuated
PubMed: 27532370
DOI: 10.1080/21645515.2016.1216286 -
Human Vaccines & Immunotherapeutics 2019The difference noted in Rotavirus vaccine efficiency between high and low income countries correlates with the lack of universal access to clean water and higher... (Review)
Review
The difference noted in Rotavirus vaccine efficiency between high and low income countries correlates with the lack of universal access to clean water and higher standards of hygiene. Overcoming these obstacles will require great investment and also time, therefore more effective vaccines should be developed to meet the needs of those who would benefit the most from them. Increasing our current knowledge of mucosal immunity, response to Rotavirus infection and its modulation by circadian rhythms could point at actionable pathways to improve vaccination efficacy, especially in the case of individuals affected by environmental enteropathy. Also, a better understanding and validation of Rotavirus entry factors as well as the systematic monitoring of dominant strains could assist in tailoring vaccines to individual's needs. Another aspect that could improve vaccine efficiency is targeting to M cells, for which new ligands could potentially be sought. Finally, alternative mucosal adjuvants and vaccine expression, storage and delivery systems could have a positive impact in the outcome of Rotavirus vaccination.
Topics: Clinical Trials as Topic; Developing Countries; Enterocytes; Gastroenteritis; Humans; Immunity, Mucosal; Rotavirus; Rotavirus Infections; Rotavirus Vaccines; Vaccination; Vaccine Potency; Vaccines, Attenuated
PubMed: 30215578
DOI: 10.1080/21645515.2018.1520583