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1.
Vaccine ; 30(10): 1767-81, 2012 Feb 27.
Article in English | MEDLINE | ID: mdl-22261411

ABSTRACT

This paper offers an overview of important veterinary viral diseases of mammals stemming from aberrant immune response. Diseases reviewed comprise those due to lentiviruses of equine infectious anaemia, visna/maedi and caprine arthritis encephalitis and feline immunodeficiency. Diseases caused by viruses of feline infectious peritonitis, feline leukaemia, canine distemper and aquatic counterparts, Aleutian disease and malignant catarrhal fever. We also consider prospects of immunoprophylaxis for the diseases and briefly other control measures. It should be realised that the outlook for effective vaccines for many of the diseases is remote. This paper describes the current status of vaccine research and the difficulties encountered during their development.


Subject(s)
Animal Diseases/prevention & control , Mammals/virology , Virus Diseases/prevention & control , Virus Diseases/veterinary , Animal Diseases/immunology , Animals , Livestock/virology , Pets/virology , Viral Vaccines , Virus Diseases/immunology
2.
Vaccine ; 30(2): 201-9, 2012 Jan 05.
Article in English | MEDLINE | ID: mdl-22107849

ABSTRACT

Infection with human influenza virus leads to serious respiratory disease. Vaccination is the most common and effective prophylactic measure to prevent influenza. Influenza vaccine manufacturing and release is controlled by the correct determination of the potency-defining haemagglutinin (HA) content. This determination is historically done by single radial immunodiffusion (SRID), which utilizes a statistical slope-ratio model to estimate the actual HA content. In this paper we describe the development and qualification of a parallel line model for analysis of HA quantification by SRID in cell culture-derived whole virus final monovalent and trivalent influenza vaccines. We evaluated plate layout, sample randomization, and validity of data and statistical model. The parallel line model was shown to be robust and reproducible. The precision studies for HA content demonstrated 3.8-5.0% repeatability and 3.8%-7.9% intermediate precision. Furthermore, system suitability criteria were developed to guarantee long-term stability of this assay in a regulated production environment. SRID is fraught with methodological and logistical difficulties and the determination of the HA content requires the acceptance of new and modern release assays, but until that moment, the described parallel line model represents a significant and robust update for the current global influenza vaccine release assay.


Subject(s)
Chemistry Techniques, Analytical/methods , Hemagglutinin Glycoproteins, Influenza Virus/analysis , Influenza Vaccines/immunology , Influenza Vaccines/standards , Technology, Pharmaceutical/standards , Humans , Models, Statistical , Quality Control , Reproducibility of Results
3.
Vet Microbiol ; 152(3-4): 304-14, 2011 Sep 28.
Article in English | MEDLINE | ID: mdl-21664078

ABSTRACT

In April 2009 a new influenza A/H1N1 strain, currently named "pandemic (H1N1) influenza 2009" (H1N1v), started the first official pandemic in humans since 1968. Several incursions of this virus in pig herds have also been reported from all over the world. Vaccination of pigs may be an option to reduce exposure of human contacts with infected pigs, thereby preventing cross-species transfer, but also to protect pigs themselves, should this virus cause damage in the pig population. Three swine influenza vaccines, two of them commercially available and one experimental, were therefore tested and compared for their efficacy against an H1N1v challenge. One of the commercial vaccines is based on an American classical H1N1 influenza strain, the other is based on a European avian H1N1 influenza strain. The experimental vaccine is based on reassortant virus NYMC X179A (containing the hemagglutinin (HA) and neuraminidase (NA) genes of A/California/7/2009 (H1N1v) and the internal genes of A/Puerto Rico/8/34 (H1N1)). Excretion of infectious virus was reduced by 0.5-3 log(10) by the commercial vaccines, depending on vaccine and sample type. Both vaccines were able to reduce virus replication especially in the lower respiratory tract, with less pathological lesions in vaccinated and subsequently challenged pigs than in unvaccinated controls. In pigs vaccinated with the experimental vaccine, excretion levels of infectious virus in nasal and oropharyngeal swabs, were at or below 1 log(10)TCID(50) per swab and lasted for only 1 or 2 days. An inactivated vaccine containing the HA and NA of an H1N1v is able to protect pigs from an infection with H1N1v, whereas swine influenza vaccines that are currently available are of limited efficaciousness. Whether vaccination of pigs against H1N1v will become opportune remains to be seen and will depend on future evolution of this strain in the pig population. Close monitoring of the pig population, focussing on presence and evolution of influenza strains on a cross-border level would therefore be advisable.


Subject(s)
Influenza A Virus, H1N1 Subtype/physiology , Influenza Vaccines/immunology , Orthomyxoviridae Infections/veterinary , Swine Diseases/immunology , Swine Diseases/prevention & control , Animals , Influenza A Virus, H1N1 Subtype/isolation & purification , Influenza A Virus, H3N2 Subtype/genetics , Influenza A Virus, H3N2 Subtype/immunology , Orthomyxoviridae Infections/immunology , Orthomyxoviridae Infections/prevention & control , Reassortant Viruses/immunology , Sus scrofa , Swine , Swine Diseases/virology , Vaccines, Inactivated/immunology
4.
Mol Gen Mikrobiol Virusol ; (4): 29-36, 2011.
Article in Russian | MEDLINE | ID: mdl-22312898

ABSTRACT

The cold-adapted, temperature sensitive and attenuated influenza master donor viruses A/Leningrad/134/17/57 (H2N2) and B/USSR/ 60/69 were used to generate the vaccine viruses to be included in live attenuated influenza vaccine. These vaccine viruses typically are 6:2 reassortant viruses containing the surface antigens hemagglutinin and neuraminidase of current wild type influenza A and influenza B viruses with the gene segments encoding the internal viral proteins, and conferring the cold-adapted, temperature sensitive and attenuated phenotype, being inherited from the master donor viruses. The 6:2 reassortant viruses were selected from co-infections between master donor virus and wild type viruses that theoretically may yield as many as 256 combinations of gene segments and thus 256 genetically different viruses. As the time to generate and isolate vaccine viruses is limited and because only 6:2 reassortant viruses are allowed as vaccine viruses, screening needs to be both rapid and unambiguous. The screening of the reassortant viruses by RT-PCRs using master donor virus and wild type virus specific primer sets was described to select both influenza A and influenza B 6:2 reassortant viruses to be used in seasonal and pandemic live attenuated vaccine.


Subject(s)
Genome, Viral/genetics , Influenza A Virus, H1N1 Subtype/genetics , Influenza A Virus, H3N2 Subtype/genetics , Influenza B virus/genetics , Influenza Vaccines/genetics , Influenza, Human/prevention & control , Reassortant Viruses/genetics , Animals , Chick Embryo , Coinfection/virology , Hemagglutinins/genetics , Humans , Influenza A Virus, H1N1 Subtype/immunology , Influenza A Virus, H3N2 Subtype/isolation & purification , Influenza B virus/immunology , Influenza, Human/epidemiology , Neuraminidase/genetics , Pandemics , RNA/genetics , RNA/isolation & purification , Reassortant Viruses/immunology , Vaccines, Attenuated/genetics , Vaccines, Attenuated/immunology
5.
Vaccine ; 28(51): 8125-31, 2010 Nov 29.
Article in English | MEDLINE | ID: mdl-20950729

ABSTRACT

The feasibility of a single-shot, low-dose vaccination against pandemic influenza was investigated. The immunogenicity and safety of whole inactivated, cell culture-derived H5N1 virus plus CoVaccine HT™ as adjuvant was tested in various animal species. In ferrets, doses of 4.0 and 7.5 µg H5N1 (NIBRG-14; A/Vietnam/1194/04; clade 1) without adjuvant gave low geometric mean haemagglutination inhibition (HI) titres (GMTs) of 21-65 three weeks after intramuscular (IM) injection. The addition of 0.25-4 mg CoVaccine HT™ resulted in GMTs of 255-1470 corresponding with 4-25-fold increases. A second immunization caused GMTs of 8914-23,525 two weeks later, which confirmed strong priming. One out of 8 ferrets injected with antigen alone and 5 out of 32 ferrets injected with adjuvanted H5N1 demonstrated minimal transient, local reactions and two animals immunized with adjuvanted H5N1 exhibited increased body temperature one day after injection. In macaques, 5 µg H5N1 with CoVaccine HT™ or aluminium hydroxide as adjuvant elicited GMTs of 172 and 11, respectively three weeks later. A second immunization resulted in GMTs of 1751 and 123, respectively four weeks later. Analysis of cross-reactivity of antibodies after the first immunization with NIBRG-14 adjuvanted plus CoVaccine HT™ revealed GMTs of 69 against NIBRG-23 (A/turkey/Turkey/1/05; clade 2.2) and 42 against IBCDC-RG-2 (A/Indonesia/5/05-like; clade 2.1.3) while titres with aluminium hydroxide were <10. After the second immunization with CoVaccine HT™, GMT against NIBRG-23 was 599 and against IBCDC-RG-2 254, while those with aluminium hydroxide were 23 and 13, respectively. No local or systemic adverse events were detected in macaques. Safety of 5 µg H5N1 plus 0, 2 or 4 mg CoVaccine HT™ was investigated in a repeated dose study in rabbits. Groups of 6 or 9 male and female animals were immunized IM three times at three week intervals. None of the animals exerted treatment-related adverse reactions during the study or at necropsy 3 or 4 days after treatment. We concluded that a low dose of whole inactivated influenza virus plus CoVaccine HT™ is a promising, single-shot vaccine against pandemic influenza.


Subject(s)
Influenza A Virus, H5N1 Subtype/immunology , Influenza Vaccines/administration & dosage , Influenza Vaccines/immunology , Vaccination/methods , Adjuvants, Immunologic/administration & dosage , Animals , Antibodies, Viral/blood , Cross Reactions , Female , Ferrets , Fever/chemically induced , Hemagglutination Inhibition Tests , Immunization, Secondary/methods , Influenza Vaccines/adverse effects , Injections, Intramuscular , Macaca , Male , Rabbits , Skin Diseases/chemically induced , Vaccines, Inactivated/administration & dosage , Vaccines, Inactivated/adverse effects , Vaccines, Inactivated/immunology
6.
Vaccine ; 28(43): 6989-96, 2010 Oct 08.
Article in English | MEDLINE | ID: mdl-20728523

ABSTRACT

Equine influenza is a contagious disease caused by equine influenza virus which belongs to the orthomyxovirus family. Outbreaks of equine influenza cause severe economic loses to the horse industry and consequently horses in competition are required to be regularly vaccinated against equine influenza. Unlike the existing inactivated vaccines, Equilis Prequenza Te is the only one able to induce protection against clinical disease and virus excretion after a primary vaccination course consisting of two vaccine applications 4-6 weeks apart until the recommended time of the third vaccination. In this paper we describe the duration of immunity profile, tested in an experimental setting according to European legislation, of this inactivated equine influenza and tetanus combination vaccine. In addition to influenza antigen, the formulation contains a second generation ISCOM (the so called ISCOMatrix) as an adjuvant. The vaccine aims at the induction of protection from the primary vaccination course until the time of annual revaccination 12 months later, against challenge with a virulent equine influenza strain. The protection against A/equine/Kentucky/95 (H3N8) at the time of annual revaccination was evidenced by a significant reduction of clinical signs of influenza, a significant reduction of virus excretion and a significant reduction of fever. The effect of the annual revaccination on the duration of immunity against influenza and tetanus was also studied by serology. For tetanus, as a consequence of the 24 months duration of immunity, an alternating annual vaccination schedule consisting of Prequenza and Prequenza Te is proposed after the first three doses of Prequenza Te.


Subject(s)
Horse Diseases/prevention & control , Influenza A Virus, H3N8 Subtype/immunology , Influenza Vaccines/immunology , Orthomyxoviridae Infections/veterinary , Tetanus Toxoid/immunology , Tetanus/veterinary , Adjuvants, Immunologic/pharmacology , Animals , Antibodies, Viral/blood , Horse Diseases/immunology , Horses/immunology , ISCOMs/immunology , Orthomyxoviridae Infections/immunology , Orthomyxoviridae Infections/prevention & control , Tetanus/immunology , Tetanus/prevention & control , Vaccination/veterinary , Vaccines, Combined/immunology
7.
J Virol ; 84(16): 7943-52, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20519384

ABSTRACT

Highly pathogenic avian influenza A viruses of the H5N1 subtype continue to circulate in poultry, and zoonotic transmissions are reported frequently. Since a pandemic caused by these highly pathogenic viruses is still feared, there is interest in the development of influenza A/H5N1 virus vaccines that can protect humans against infection, preferably after a single vaccination with a low dose of antigen. Here we describe the induction of humoral and cellular immune responses in ferrets after vaccination with a cell culture-derived whole inactivated influenza A virus vaccine in combination with the novel adjuvant CoVaccine HT. The addition of CoVaccine HT to the influenza A virus vaccine increased antibody responses to homologous and heterologous influenza A/H5N1 viruses and increased virus-specific cell-mediated immune responses. Ferrets vaccinated once with a whole-virus equivalent of 3.8 microg hemagglutinin (HA) and CoVaccine HT were protected against homologous challenge infection with influenza virus A/VN/1194/04. Furthermore, ferrets vaccinated once with the same vaccine/adjuvant combination were partially protected against infection with a heterologous virus derived from clade 2.1 of H5N1 influenza viruses. Thus, the use of the novel adjuvant CoVaccine HT with cell culture-derived inactivated influenza A/H5N1 virus antigen is a promising and dose-sparing vaccine approach warranting further clinical evaluation.


Subject(s)
Adjuvants, Immunologic/administration & dosage , Influenza A Virus, H5N1 Subtype/immunology , Influenza Vaccines/immunology , Vaccination/methods , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Body Weight , CD8-Positive T-Lymphocytes/immunology , Disease Models, Animal , Female , Ferrets , Flow Cytometry , Hemagglutination Inhibition Tests , Histocytochemistry , Immunohistochemistry , Lung/pathology , Lung/virology , Microscopy , Neutralization Tests , Orthomyxoviridae Infections/prevention & control , Pharynx/virology , Vaccines, Inactivated/immunology
8.
Article in Russian | MEDLINE | ID: mdl-21381376

ABSTRACT

AIM: To identify the genes that are responsible for attenuation of donor viruses for live influenza vaccine. MATERIALS AND METHODS. Analysis of phenotypical properties of reassortants of wild type A and B influenza viruses with A/Leningrad/134/17/57 (H2N2) (A17) and B/USSR/60/69 (B60) master donor viruses was performed by comparison of their capability to grow at different temperatures in chicken eggs or/and MDCK cells. RESULTS: Ts phenotype of 178 reassortants of A17 with current non-ts influenza A wild type viruses and 33 reassortants of B60 with current non-ts influenza B wild type viruses were evaluated. Reassortants inherited two polymerase genes PB2 and PA or PB 1 from A17 regularly demonstrated ts phenotype. The polymerase PA and PB2 gene segments of B60 independently controlled manifestation of ts phenotype of B60 based reassortants. The other nonpolymerase genes played no role in manifestation of ts phenotype of reassortants A17 and B60 viruses. CONCLUSION: The molecular basis for the development ts phenotype of both A and B influenza vaccine reassortant viruses determined by polymerase genes complex.


Subject(s)
Influenza A virus/immunology , Influenza B virus/immunology , Influenza Vaccines/immunology , RNA-Dependent RNA Polymerase/immunology , Viral Proteins/immunology , Amino Acid Substitution , Animals , Cell Line , Chick Embryo , Dogs , Influenza A virus/genetics , Influenza B virus/genetics , Influenza Vaccines/genetics , RNA-Dependent RNA Polymerase/genetics , Reassortant Viruses/genetics , Reassortant Viruses/immunology , Serial Passage , Temperature , Vaccines, Attenuated/genetics , Vaccines, Attenuated/immunology , Viral Proteins/genetics , Virus Replication
9.
Vaccine ; 27(49): 6833-9, 2009 Nov 16.
Article in English | MEDLINE | ID: mdl-19772942

ABSTRACT

A candidate influenza H5N1 vaccine based on cell-culture-derived whole inactivated virus and the novel adjuvant CoVaccineHT was evaluated in vitro and in vivo. To this end, mice were vaccinated with the whole inactivated influenza A/H5N1 virus vaccine with and without CoVaccineHT and virus-specific antibody and cellular immune responses were assessed. The addition of CoVaccineHT increased virus specific primary and secondary antibody responses against the homologous and an antigenically distinct heterologous influenza A/H5N1 strain. The superior antibody responses induced with the CoVaccineHT-adjuvanted vaccine correlated with the magnitude of the virus-specific CD4+ T helper cell responses. CoVaccineHT did not have an effect on the magnitude of the CD8+ T cell response. In vitro, CoVaccineHT upregulated the expression of co-stimulatory molecules both on mouse and human dendritic cells and induced the secretion of pro-inflammatory cytokines TNF-alpha, IL-6, IL-1beta and IL-12p70 in mouse- and IL-6 in human dendritic cells. Inhibition experiments indicated that the effect of CoVaccineHT is mediated through TLR4 signaling. These data suggest that CoVaccineHT also will increase the immunogenicity of an influenza A/H5N1 vaccine in humans.


Subject(s)
Adjuvants, Immunologic/pharmacology , Dendritic Cells/immunology , Influenza Vaccines/immunology , Orthomyxoviridae Infections/immunology , Adult , Animals , Antibodies, Viral/blood , Antibody Formation , B7-1 Antigen/metabolism , B7-2 Antigen/metabolism , CD8-Positive T-Lymphocytes/immunology , Cytokines/metabolism , Female , Humans , Influenza A Virus, H5N1 Subtype/immunology , Mice , Mice, Inbred C57BL , Middle Aged , Neutralization Tests , Orthomyxoviridae Infections/prevention & control , T-Lymphocytes, Helper-Inducer/immunology
10.
Vaccine ; 27(40): 5530-7, 2009 Sep 04.
Article in English | MEDLINE | ID: mdl-19607950

ABSTRACT

Equine influenza is a contagious diseases caused by equine influenza viruses which belong to the orthomyxovirus family. Outbreaks of equine influenza cause severe economic loses to the horse industry and consequently competition horses are required to be regularly vaccinated against equine influenza. Currently available inactivated vaccines are only able to induce protection against clinical disease and virus excretion after a primary vaccination course consisting of three vaccine applications at 4-6 and 22-26 weeks apart, respectively. It has been suggested that these vaccines induce no adequate protection in horses at 22-26 weeks (5 months) in the primary vaccination course (immediately prior to the last booster), despite various alternative vaccination regimens proposed. In this paper we describe the efficacy and safety profile, tested in an experimental setting according to European legislation of a novel inactivated equine influenza vaccine formulation (Prequenza). This formulation consists besides influenza antigen, of second generation ISCOM-Matrix as an adjuvant. The vaccine aims at the induction of protection from the onset of immunity, i.e. after the first two vaccine applications, until the first booster given 5 months later, against challenge with a virulent equine influenza strain. The protection against A/equine/Kentucky/95 (H3N8) was evidenced by a reduction of clinical signs of influenza, a reduction of virus excretion and a reduction of fever. The vaccine was shown to be safe in pregnant mares, foals and is used safely since 2 years as a commercial vaccine in Europe.


Subject(s)
Adjuvants, Immunologic , Horse Diseases/prevention & control , ISCOMs/immunology , Influenza Vaccines/immunology , Orthomyxoviridae Infections/veterinary , Animals , Antigens, Viral/immunology , Female , Horse Diseases/immunology , Horses/immunology , Immunization, Secondary/veterinary , Influenza A Virus, H3N8 Subtype/immunology , Orthomyxoviridae Infections/immunology , Orthomyxoviridae Infections/prevention & control , Pregnancy , Vaccines, Inactivated/immunology
11.
Vaccine ; 27(12): 1797-1810, 2009 Mar 13.
Article in English | MEDLINE | ID: mdl-19402200

ABSTRACT

Since the refinement of tissue culture techniques for virus isolation and propagation from the mid 1960s onwards, veterinary virology has received much academic and industrial interest, and has now become a major global industry largely centred on vaccine development against economically important virus diseases of food animals. Bio-tech approaches have been widely used for improved vaccines development. While many viral diseases are controlled through vaccination, many still lack safe and efficacious vaccines. Additional challenges faced by academia, industry and governments are likely to come from viruses jumping species and also from the emergence of virulent variants of established viruses due to natural mutations. Also viral ecology is changing as the respective vectors adapt to new habitats as has been shown in the recent incursion by bluetongue virus into Europe. In this paper the current vaccines for livestock, horses and birds are described in a species by species order. The new promising bio-tech approaches using reverse genetics, non-replicating viral vectors, alpha virus vectors and genetic vaccines in conjunction with better adjuvants and better ways of vaccine delivery are discussed as well


Subject(s)
Animal Diseases/immunology , Animal Diseases/prevention & control , Animals, Domestic/immunology , Bird Diseases/immunology , Bird Diseases/prevention & control , Horse Diseases/immunology , Horse Diseases/prevention & control , Virus Diseases/immunology , Virus Diseases/prevention & control , Animals , Horses , Sheep , Sheep Diseases/immunology , Sheep Diseases/prevention & control , Swine , Swine Diseases/immunology , Swine Diseases/prevention & control
12.
Vaccine ; 27(4): 491-504, 2009 Jan 22.
Article in English | MEDLINE | ID: mdl-19041354

ABSTRACT

In this article we review important established, newly emergent and potential viral diseases of cats, dogs and rabbits. Topics covered include virus epidemiology, disease pathogenesis, existing and prospective immunoprophylaxis against the viruses. For some feline viruses, notably the immunodeficiency virus, leukaemia virus and peritonitis virus, available vaccines are poorly efficacious but there are good prospects for this. A further challenge for the industry is likely to be due to viruses jumping species and the emergence of more virulent variants of established viruses resulting from mutations as has been the case for the canine parvovirus, coronaviruses and feline calicivirus.


Subject(s)
Animal Diseases/immunology , Animal Diseases/virology , Viral Vaccines/immunology , Virus Diseases/veterinary , Animal Diseases/prevention & control , Animals , DNA Viruses/physiology , RNA Viruses/physiology , Virus Diseases/immunology , Virus Diseases/prevention & control
13.
Vet J ; 178(1): 7-20, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18313956

ABSTRACT

Veterinary vaccines currently available in Europe and in other parts of the world are developed by the veterinary pharmaceutical industry. The development of a vaccine for veterinary use is an economic endeavour that takes many years. There are many obstacles along the path to the successful development and launch of a vaccine. The industrial development of a vaccine for veterinary use usually starts after the proof of concept that is based on robust academic research. A vaccine can only be made available to the veterinary community once marketing authorisation has been granted by the veterinary authorities. This review gives a brief description of the regulatory requirements which have to be fulfilled before a vaccine can be admitted to the market. Vaccines have to be produced in a quality controlled environment to guarantee delivery of a product of consistent quality with well defined animal and consumer safety and efficacy characteristics. The regulatory and manufacturing legislative framework in which the development takes place is described, as well as the trend in developments in production systems. Recent developments in bacterial, viral and parasite vaccine research and development are also addressed and the development of novel adjuvants that use the expanding knowledge of immunology and disease pathology are described.


Subject(s)
Animal Diseases/prevention & control , Drug Industry/economics , Vaccines/immunology , Animals , Drug Industry/organization & administration , Europe
14.
Vet J ; 2008 Mar 04.
Article in English | MEDLINE | ID: mdl-18304846

ABSTRACT

This article has been withdrawn consistent with Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The Publisher apologizes for any inconvenience this may cause.

15.
Vet J ; 174(3): 592-8, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17560150

ABSTRACT

Conventional equine influenza vaccination schedules consist of a primary course of two vaccinations given 4-6 weeks apart followed by a third vaccination (booster) given approximately 5 months later. In between the primary course and the third vaccination, horses are generally considered not to be adequately protected against influenza. This study aimed to investigate whether Thoroughbred foals would benefit from a vaccination schedule in which the third vaccination was given earlier than in conventional vaccination schedules. The vaccines used were an inactivated whole virus equine influenza vaccine and an inactivated whole virus combination vaccine containing equine influenza and equine herpesvirus antigens. Four groups of foals were vaccinated with the two vaccines according to a conventional and an accelerated vaccination schedule in which the third vaccination was given 14 weeks after the first administration. In both groups, the fourth vaccination was given at the normally recommended interval of 26 weeks after the third vaccination for the combination vaccine and 52 weeks after the third vaccination with the influenza only vaccine. The horses were 4-11 months of age and seronegative for influenza. Immunological responses after vaccination were monitored for several months using the single radial haemolysis test. The results indicated that 28 weeks after the first vaccination, antibody levels in horses vaccinated according to the accelerated schedule were not significantly higher than in horses vaccinated according to the conventional schedule. In addition, the total level of antibody production (area under the curve) was not significantly different at that point although antibody titres were slightly higher (but not significantly so) between 16-30 weeks in the accelerated schedule. Between the third and fourth doses, horses vaccinated according to the accelerated schedule had antibodies against influenza below the level required for clinical protection for 39 and 18 weeks for the influenza only and the combination vaccine, respectively, whereas those vaccinated according to the conventional schedule had antibody titres below the level for clinical protection for 9-15 weeks in the corresponding period for both vaccines. Horses vaccinated according to the accelerated schedule with the combination vaccine had lower antibody titres after the fourth vaccination than those vaccinated according to the conventional schedule after the third vaccination, although antibody titres prior to vaccination were similar. For the influenza only vaccine, titres after the accelerated fourth administration were not different to those after the conventional third vaccination. There was no benefit from early booster vaccinations with the vaccines used in this study, so for these vaccines the conventional schedule provided better protection than the selected accelerated alternative. This may contrast with some other vaccine formulations, although a direct comparison using similar protocols has not been made.


Subject(s)
Horse Diseases/prevention & control , Immunization, Secondary/veterinary , Influenza A Virus, H3N8 Subtype/immunology , Influenza Vaccines/administration & dosage , Influenza Vaccines/immunology , Animals , Drug Administration Schedule/veterinary , Female , Horses , Male , Vaccination/veterinary
16.
Vet J ; 167(2): 150-7, 2004 Mar.
Article in English | MEDLINE | ID: mdl-14975389

ABSTRACT

It has been recommended that modern equine influenza vaccines should contain an A/equi-1 strain and A/equi-2 strains of the American and European-like subtype. We describe here the efficacy of a modern updated inactivated equine influenza-herpesvirus combination vaccine against challenge with a recent American-like isolate of equine influenza (A/equine-2/Kentucky/95 (H3N8). The vaccine contains inactivated Influenza strains A-equine-1/Prague'56, A-equine-2/Newmarket-1/'93 (American lineage) and A-equine-2/ Newmarket-2/93 (Eurasian lineage) and inactivated EHV-1 strain RacH and EHV-4 strain V2252. It is adjuvanted with alhydrogel and an immunostim. Horses were vaccinated at the start of the study and 4 weeks later. Four, six and eight weeks after the first vaccination high anti-influenza antibody titres were found in vaccinated horses, whereas at the start of the study all horses were seronegative. After the challenge, carried out at 8 weeks after the first vaccination, nasal swabs were taken, rectal temperatures were measured and clinical signs were monitored for 14 days. In contrast to unvaccinated control horses, vaccinated animals shed hardly any virus after challenge, and the appearance of clinical signs of influenza such as nasal discharge, coughing and fever were reduced in the vaccinated animals. Based on these observations, it was concluded that the vaccine protected against clinical signs of influenza and, more importantly, against virus excretion induced by an American-like challenge virus strain. In a second experiment the duration of the immunity induced by this vaccine was assessed serologically. Horses were vaccinated at the start of the study and 6 and 32 weeks later. Anti-influenza antibody titres were determined in bloodsamples taken at the first vaccination, and 2, 6, 8, 14, 19, 28, 32, 37, 41, 45 and 58 weeks after the first vaccination. Vaccinated horses had high anti-influenza antibody titres, above the level for clinical protection against influenza, against all strains present in the vaccine until 26 weeks after the third vaccination.


Subject(s)
Herpesviridae Infections/veterinary , Herpesvirus 4, Equid/immunology , Horse Diseases/immunology , Horse Diseases/prevention & control , Influenza A virus/immunology , Orthomyxoviridae Infections/veterinary , Viral Vaccines/immunology , Animals , Animals, Newborn , Herpesviridae Infections/immunology , Herpesviridae Infections/prevention & control , Horses , Orthomyxoviridae Infections/immunology , Orthomyxoviridae Infections/prevention & control , Vaccines, Combined/immunology
18.
J Immunol Methods ; 264(1-2): 11-7, 2002 Jun 01.
Article in English | MEDLINE | ID: mdl-12191504

ABSTRACT

Using the area under the curve (AUC) concept as is commonly used in pharmaceutical bioequivalence studies, the bioequivalence of three equine influenza vaccines was demonstrated. A retrospective analysis was performed using this technique on data generated in three trials in which each of the three vaccines had been used. In total, data from 63 pony and horse foals were used. The AUC of the single radial hemolysis (SRH) titres against Influenza A/equi-1/Prague/56 (Pr/56), A/equi-2/Newmarket-1/93, and A/equi-2/Suffolk/89 (Suf/89) were calculated for each horse. It was concluded that calculation of the AUC from four time-points permitted a suitable estimate for vaccine potency. Using pooled data, it appeared that the AUC permitted better evaluation of vaccine potency than simply considering the highest post vaccinal titre (Titremax). In two studies, a minimal value for the AUC was associated with protection against Influenza (H3N8) challenge 50-153 days later.


Subject(s)
Area Under Curve , Influenza A virus/immunology , Influenza Vaccines/therapeutic use , Vaccination/statistics & numerical data , Animals , Antibodies, Viral/biosynthesis , Antibodies, Viral/blood , Blood Specimen Collection/statistics & numerical data , Blood Specimen Collection/veterinary , Horse Diseases/immunology , Horse Diseases/prevention & control , Horses , Immunization, Secondary/statistics & numerical data , Immunization, Secondary/veterinary , Immunodiffusion/statistics & numerical data , Immunodiffusion/veterinary , Influenza Vaccines/administration & dosage , Injections, Intramuscular , Orthomyxoviridae Infections/immunology , Orthomyxoviridae Infections/prevention & control , Orthomyxoviridae Infections/veterinary , Retrospective Studies , Therapeutic Equivalency , Vaccination/veterinary
19.
Vaccine ; 19(30): 4307-17, 2001 Jul 20.
Article in English | MEDLINE | ID: mdl-11457558

ABSTRACT

Pregnant mares and young foals were vaccinated with Duvaxyn EHV1,4, an inactivated and adjuvanted vaccine containing both the EHV-1 and 4 antigens. SN and CF antibody titres were induced two weeks after first vaccination. Antibody levels were boosted after second vaccination, however they never reached the levels induced after virus challenge. Young foals were challenged with virulent EHV-1 and EHV-4 field viruses. Pregnant mares were challenged with the highly abortigenic EHV-1 strain Ab4. Vaccinated animals showed a clear reduction in clinical signs and virus excretion compared to unvaccinated control animals. Log transformed antibody levels could be correlated to duration of virus excretion. The incidence of EHV-1 induced abortions was drastically reduced in vaccinated mares. Therefore, although vaccinated animals are not fully protected against disease, Duvaxyn EHV1,4 clearly reduces clinical symptoms, the duration of virus shedding and the quantity of virus shed. It can be concluded that vaccination of foals and pregnant mares with Duvaxyn EHV1,4 significantly reduces the risk of abortions and outbreaks of respiratory disease caused by circulating field viruses.


Subject(s)
Herpesviridae Infections/veterinary , Herpesvirus 1, Equid/immunology , Herpesvirus 4, Equid/immunology , Horse Diseases/prevention & control , Vaccination/veterinary , Viral Vaccines/immunology , Abortion, Veterinary/prevention & control , Animals , Antibodies, Viral/blood , Female , Fever/etiology , Herpesviridae Infections/prevention & control , Herpesvirus 1, Equid/isolation & purification , Herpesvirus 4, Equid/isolation & purification , Horses , Nasopharynx/virology , Pregnancy , Vaccines, Inactivated/immunology , Viremia/virology
20.
Vet Q ; 23(4): 210-7, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11765243

ABSTRACT

An adjuvanted vaccine containing inactivated equine influenza, herpesvirus antigens, and tetanus toxoid was administered to young seronegative foals of 8 months of age by deep intramuscular injection in the neck (Group A). The first two vaccinations were given 4 weeks apart. The third was administered 6 months later. Another group of foals (Group B) was vaccinated according to the same scheme at the same time with monovalent equine herpes virus (EHV) vaccine (EHV1.4) vaccine. Antibody responses to the equine influenza (single radial haemolysis; SRH) and tetanus (ToBi ELISA) components of the vaccines were examined from first vaccination until 1 year after the third vaccination. The influenza components of the combination vaccine induced high antibody titres at two weeks after the second vaccination whereafter titres declined until the time of the third vaccination. After the third vaccination, the titres rose rapidly again to remain high for at least 1 year. Antibody titres against tetanus peaked only after the third vaccination but remained high enough to offer protective immunity for at least 1 year. Foals vaccinated with monovalent EHV1.4 remained seronegative for influenza and tetanus throughout the study. Four and a half months after the third vaccination of groups A and B, a third group of animals was vaccinated twice with monovalent EHV1.4 vaccine 4 weeks apart (Group C). Two weeks after the administration of the second dose in the later group, all groups (A, B, C and an unvaccinated control group D) were challenged with EHV-4. Vaccinated foals (Group A, B, C) showed a clear reduction of clinical symptoms and virus excretion after EHV-4 challenge compared with the unvaccinated control foals. No difference could be demonstrated among the vaccinated groups, suggesting that the combination vaccine protects as well as the monovalent vaccine. In EHV1.4-vaccinated foals both antigenic fractions induced clear protection up to 6 months after vaccination (9). It can therefore be anticipated that the efficacy of the combination vaccine against EHV-1 challenge is similar to the efficacy against EHV-1 induced by EHV1.4 vaccination.


Subject(s)
Adjuvants, Immunologic/administration & dosage , Herpesviridae Infections/veterinary , Horse Diseases/virology , Influenza A virus/immunology , Tetanus Toxoid/immunology , Tetanus/immunology , Tetanus/prevention & control , Vaccination/veterinary , Animals , Antibody Formation , Herpesviridae Infections/immunology , Herpesviridae Infections/prevention & control , Herpesvirus 1, Equid/immunology , Herpesvirus 4, Equid/immunology , Horse Diseases/prevention & control , Horses , Time Factors
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