Efficacy of a novel inactivated Lawsonia intracellularis vaccine in pigs against experimental infection and under field conditions.

The efficacy of a novel inactivated Lawsonia intracellularis vaccine, Porcilis® Lawsonia, was compared to that of a commercially available live attenuated vaccine in three experimental vaccination-challenge studies in pigs. The efficacy of the new vaccine was further tested under field conditions on a farm with a history of acute ileitis. The novel inactivated vaccine consists of a freeze-dried antigen fraction that is dissolved just prior to use in either the adjuvant or in Porcilis® PCV M Hyo; an existing combination vaccine against porcine circovirus type 2 and Mycoplasma hyopneumoniae. The three experimental vaccination-challenge trials had a similar design and for each trial 75 piglets were used, randomly allotted to three groups of 25 piglets. The pigs were vaccinated at 4 or 5 weeks of age with either Porcilis® Lawsonia in adjuvant or in associated mixed use with Porcilis® PCV M Hyo (group 1), with the live vaccine (group 2), or left as unvaccinated controls (group 3). The pigs were challenged with virulent Lawsonia intracellularis 3, 4 or 17 weeks after vaccination. Post-challenge the pigs were evaluated for clinical signs, average daily weight gain, shedding and macroscopic as well as microscopic immuno-histological ileum lesion scores. In the field study, the mortality and key performance parameters were evaluated over a period of 8 months. The results of all three experimental vaccination-challenge trials showed that Porcilis® Lawsonia induced statistically significant protection against experimental Lawsonia intracellularis infection. This was demonstrated by lower clinical scores, improved weight gain, reduction of Lawsonia intracellularis shedding and reduction of macroscopic as well as microscopic ileum lesion scores when compared to the controls. The protection induced was superior to that of the commercially available live vaccine. In the field study, Porcilis® Lawsonia proved to be highly efficacious; reducing Lawsonia associated mortality to zero and improving key production parameters.

Efficacy of a non-updated, Matrix-C-based equine influenza subunit-tetanus vaccine following Florida sublineage clade 2 challenge.

Assessing the ability of current equine influenza vaccines to provide cross-protection against emerging strains is important. Horses not vaccinated previously and seronegative for equine influenza based on haemagglutination inhibition (HI) assay were assigned at random to vaccinated (n=7) or non-vaccinated (control, n=5) groups. Vaccination was performed twice four weeks apart with a 1 ml influenza subunit (A/eq/Prague/1/56, A/eq/Newmarket/1/93, A/eq/Newmarket/2/93), tetanus toxoid vaccine with Matrix-C adjuvant (EquilisPrequenza Te). All the horses were challenged individually by aerosol with A/eq/Richmond/1/07 three weeks after the second vaccination. Rectal temperature, clinical signs, serology and virus excretion were monitored for 14 days after challenge. There was no pain at the injection site or increases in rectal temperature following vaccination. Increases in rectal temperature and characteristic clinical signs were recorded in the control horses. Clinical signs were minimal in vaccinated horses. Clinical (P=0.0345) and total clinical scores (P=0.0180) were significantly lower in the vaccinated than in the control horses. Vaccination had a significant effect on indicators of viraemia - the extent (P=0.0006) and duration (P=<0.0001) of virus excretion and the total amount of virus excreted (AUC, P=0.0006). Vaccination also had a significant effect (P=0.0017) on whether a horse was positive or negative for virus excretion during the study. Further research is needed to fully understand the specific properties of this vaccine that may contribute to its cross-protective capacity.

Duration of immunity induced by an equine influenza and tetanus combination vaccine formulation adjuvanted with ISCOM-Matrix.

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.

The first safe inactivated equine influenza vaccine formulation adjuvanted with ISCOM-Matrix that closes the immunity gap.

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.