Vaccination against porcine circovirus

Abstract

The present invention relates to compositions and methods for treating or preventing disease caused by porcine circovirus. In particular, the present invention discloses a method for controlling PCV infection or disease in pig herds, the method comprising (i) vaccinating sows against PCV at the time of weaning, and (ii) vaccinating piglets against PCV at 2-7 weeks of age.

Description

[Technical Field]

[0001] The present invention relates to compositions and methods for treating or preventing disease caused by porcine circovirus.

[0002] Porcine circoviruses are a major class of viruses that infect pigs. Several types of PCVs have been reported, including PCV1, PCV2, and PCV3. These viruses are present worldwide, with PCV2 infecting the majority of pig herds. While some viruses are nonpathogenic, others, including PCV2a, PCV2b, PCV2d, and possibly PCV3, can cause disease (PCVD). PCV-associated diseases include postweaning multisystemic wasting syndrome (PMWS), porcine dermatitis and nephropathy syndrome (PDNS), porcine respiratory disease complex (PRDC), reproductive failure, granulomatous enteritis, exudative epidermitis, necrotizing lymphadenitis, and congenital tremors, among others.

[0003] Therefore, the management of PCV infection and related diseases (PCVD) in pig herds is a major concern for breeders. Today, management is primarily based on vaccination. Currently, various PCV vaccines, especially anti-PCV2 vaccines, are available for use in piglets. These vaccines are either inactivated (e.g., killed) or subunit vaccines. PCV vaccines, such as PCV2 vaccines, can reduce viral load and control PCVD, for example by reducing virus-induced lesions in lymphoid tissues. Therefore, depending on the condition and circumstances of the vaccinated pig, these vaccines may be fully effective. However, it has been reported that maternal immunity can negatively interfere with the efficacy of such vaccines in piglets. In particular, it has been noted that such interference may be related, for example, to the piglet's age at vaccination, the timing of vaccination, and the level of maternal immunity. Studies have shown that high levels of maternal antibodies interfere with the humoral immune response after PCV2 vaccination in piglets

[22] . In piglets with high levels of passive immunity, a decrease in antibody levels was observed upon vaccination. Furthermore, Haake et al.

[11] suggested that vaccination at one week of age may alter the induction of active humoral immunity in piglets.

[0004] Although the exact cause of MDA interference is still a subject of investigation, there is a demand for optimized anti-PCV vaccination strategies or regimens that can provide strong protection to pig herds.

[0005] The present application provides such novel methods for vaccinating pigs against PCV and for controlling PCV infection or disease in pig herds.

[0006] More specifically, the present invention relates to a method for controlling PCV infection or disease in a pig herd, the method comprising (i) vaccinating sows against PCV at the time of weaning and (ii) vaccinating their piglets against PCV at 2 to 7 weeks of age.

[0007] It should be understood that according to the methods of the present invention, sows are vaccinated against PCV at the time of weaning their piglets.

[0008] We investigated the clinical protection (vaccine efficacy) afforded by this novel vaccination regimen and found that a single dose of vaccine provided sufficient protection without the need to assess passively acquired immunity from gilts and sows. The combination of vaccinating sows at weaning and their piglets at 2 to 7 weeks of age is highly effective in controlling PCV infection and related diseases in pig herds and appears to be unaffected by interference from maternal immunity.

[0009] More specifically, the present invention relates to a method for controlling PCV infection or disease in pigs, the method comprising vaccinating sows and their piglets against PCV, wherein (i) the sows are vaccinated against PCV at weaning, and (ii) the piglets are vaccinated against PCV at 2 to 7 weeks of age.

[0010] The present invention also relates to a method for vaccinating pigs against PCV infection or disease, the method comprising vaccinating sows and their piglets, wherein (i) the sows are vaccinated against PCV at weaning, and (ii) the piglets are vaccinated against PCV at between 2 and 7 weeks of age.

[0011] The present invention also particularly relates to a method for inducing protective anti-PCV immunity in pigs, the method comprising vaccinating sows and their piglets against PCV, wherein (i) the sows are vaccinated against PCV at weaning, and (ii) the piglets are vaccinated against PCV at 2 to 7 weeks of age.

[0012] The present invention also relates to a method for controlling PCV infection or disease in a swine herd, the method comprising (i) vaccinating sows against PCV at the time of weaning, and (ii) vaccinating piglets against PCV at 2 to 7 weeks of age; preferably, the method comprises vaccinating sows and their piglets against PCV, wherein (i) the sows are vaccinated against PCV at the time of weaning, and (ii) the piglets are vaccinated against PCV at 3 to 6 weeks of age.

[0013] The present invention also relates to a PCV vaccine for use in a method for controlling PCV infection or disease in a swine herd, the method comprising (i) vaccinating sows against the PCV at the time of weaning, and (ii) vaccinating piglets against the PCV at 2-7 weeks of age. Preferably, the method comprises vaccinating sows and their piglets against the PCV, wherein (i) the sows are vaccinated against the PCV at the time of weaning, and (ii) the piglets are vaccinated against the PCV at 3-6 weeks of age.

[0014] The present invention also relates to a PCV vaccine for use in vaccinating pigs against PCV infection or disease, the PCV vaccine for which use comprises vaccinating sows and their piglets, wherein (i) the sows are vaccinated against PCV at weaning, and (ii) the piglets are vaccinated against PCV at 2 to 7 weeks of age.

[0015] The present invention also relates to a PCV vaccine for use in inducing protective anti-PCV immunity in pigs, the PCV vaccine for which comprises vaccinating sows and their piglets against PCV, wherein (i) the sows are vaccinated against PCV at weaning, and (ii) the piglets are vaccinated against PCV at 2 to 7 weeks of age.

[0016] The present invention also relates to the use of a PCV antigen for the manufacture of a vaccine for controlling PCV infection or disease in a swine herd by (i) vaccinating sows against PCV at the time of weaning and (ii) vaccinating piglets against PCV at 2 to 7 weeks of age. Preferably, the use comprises vaccinating sows and their piglets against PCV, wherein (i) the sows are vaccinated against PCV at the time of weaning and (ii) the piglets are vaccinated against PCV at 3 to 6 weeks of age.

[0017] The present invention also relates to the use of a PCV antigen for the manufacture of a composition for vaccinating pigs against PCV infection or disease by vaccinating sows and their piglets, wherein (i) the sows are vaccinated against PCV at weaning, and (ii) the piglets are vaccinated against PCV at 2 to 7 weeks of age.

[0018] The present invention also relates to the use of a PCV antigen for the manufacture of a PCV vaccine for inducing protective anti-PCV immunity in pigs by vaccinating sows and their piglets against PCV, wherein (i) the sows are vaccinated against PCV at weaning, and (ii) the piglets are vaccinated against PCV at 2 to 7 weeks of age.

[0019] The inventors have discovered that when sows are vaccinated at weaning (i.e., at the time their piglets are weaned), the next generation of piglets are highly responsive to vaccination at 2-7 weeks of age. As a result, piglets can be effectively protected with a single vaccination, and sows can be vaccinated at each weaning.

[0020] In a most preferred embodiment, piglets are vaccinated at 3 or 6 weeks of age.

[0021] In a typical embodiment, sows and their piglets are vaccinated at the time of weaning, essentially the same day.

[0022] In certain advantageous embodiments, vaccination of the sows and piglets comprises a single injection of the PCV vaccine, such as a single intramuscular injection of the PCV vaccine.

[0023] The present invention may be used with any PCV vaccine and is particularly suitable for PCV2 vaccination, and more particularly for vaccination using an inactivated PCV2 vaccine.

[0024] Vaccine Composition As used herein, the term "vaccine" includes any composition that can be used to induce, stimulate, or amplify an immune response in an animal (e.g., a pig) against PCV.

[0025] Thus, a vaccine comprises at least one antigen from a target virus, which may be, but is not limited to, the whole virus (inactivated or attenuated form), an extract or fraction thereof, an isolated viral protein or other viral component, a nucleic acid encoding it, or a fragment or derivative thereof.

[0026] In addition to the antigen (or immunogen), the vaccine may contain other components known per se by those skilled in the art, such as pharmaceutically acceptable carriers, excipients, diluents, adjuvants, lyophilization stabilizers, wetting or emulsifying agents, pH buffering agents, gelling or viscosity-increasing additives, or preservatives, depending on the route of administration.

[0027] Examples of pharmaceutically acceptable carriers, excipients or diluents include demineralized water or distilled water saline; vegetable oils such as peanut oil, arachis oil, safflower oil, olive oil, cottonseed oil, corn oil, sesame oil, or coconut oil; silicone oils including polysiloxanes such as methylpolysiloxane, phenylpolysiloxane, and methylphenylpolysorboxane; volatile silicones; mineral oils such as light liquid paraffin oil or heavy liquid paraffin oil; squalene; methylcellulose, ethylcellulose, carboxymethylcellulose, carboxymethylcellulose sodium salt, or hydroxypropylmethylcellulose. Examples of suitable carriers include, but are not limited to, cellulose derivatives such as cellulose acetate; lower alkanols, such as ethanol or isopropanol; lower aralkanols; lower polyalkylene glycols or lower alkylene glycols, such as polyethylene glycol, polypropylene glycol, ethylene glycol, propylene glycol, 1,3-butylene glycol, or glycerin; fatty acid esters such as isopropyl palmitate, isopropyl myristate, and ethyl oleate; polyvinylpyrrolidone; agar; carrageenan; tragacanth or acacia gum, and petrolatum. Typically, the carrier(s) form 10% to 99.9% by weight of the vaccine composition and may be buffered by conventional methods using reagents known in the art, such as sodium hydrogen phosphate, sodium dihydrogen phosphate, potassium hydrogen phosphate, potassium dihydrogen phosphate, or mixtures thereof.

[0028] Examples of adjuvants include, but are not limited to, oil-in-water emulsions, aluminum hydroxide (alum), immune stimulating complexes, nonionic block polymers or copolymers, cytokines (such as IL-1, IL-2, IL-7, IFN-α, IFN-β, IFN-γ, etc.), saponin, monophosphoryl lipid A (MLA), muramyl dipeptide (MDP), etc. Other suitable adjuvants include, for example, aluminum potassium sulfate, heat-labile or heat-stable enterotoxin isolated from Escherichia coli, cholera toxin or its B subunit, diphtheria toxin, tetanus toxin, pertussis toxin, Freund's incomplete or complete adjuvant, etc. Toxin-based adjuvants such as diphtheria toxin, tetanus toxin, and pertussis toxin can be inactivated prior to use, for example, by treatment with formaldehyde.

[0029] Examples of lyophilization stabilizers can be, for example, carbohydrates such as sorbitol, mannitol, starch, sucrose, dextran or glucose, proteins such as albumin or casein, and derivatives thereof.

[0030] Vaccines may also be used against Actinobacillus pleuropneunomia; adenovirus; alphaviruses such as eastern equine encephalitis virus; Balantidium coli; Bordetella bronchiseptica; Brachyspira spp., preferably B. hyodyentheriae, B. pilosicoli, B. innocens, Brucella suis, preferably biotypes 1, 2 and 3; classical swine fever virus, African swine fever virus; Chlamydia and Chlamydophila spp., preferably C. pecorum and C. abortus; Clostridium spp., preferably Cl. difficile, Cl. perfringens types A, B, C, Cl. novyi, Cl. septicum, Cl. tetani; gastrointestinal and respiratory coronaviruses; Cryptosporidium parvum; Eimeria spp.; Eerythrozoonis suis, now named Mycoplasma haemosuis; Erysipelothrix rhusiopathiae; Escherichia coli; Haemophilus parasuis, preferably subtypes 1, 7, and 14; hemagglutinating encephalomyelitis virus; lsospora suis; Japanese encephalitis virus; Lawsonia intracellularis; Leptospira spp., preferably Leptospira australis, Leptospira canicola, Leptospira grippotyphosa, Leptospira icterohaemorrhagicae, Leptospira interrogans, Leptospira Pomona, and Leptospira tarassovi; Mannheimia haemolytica; Mycobacterium spp., preferably M. avium, M. intracellular, and M.Antigens from other pathogens may also be included, such as Mycoplasma hyponeumoniae, parvovirus, Pasteurella multocida, porcine cytomegalovirus, porcine parvovirus, porcine reproductive and respiratory syndrome virus, pseudorabies virus, rotavirus, Hagiyama virus, Salmonella spp., preferably S. thyhimurium and S. choleraesuis, Staphylococcus spp., preferably S. hyicus, Streptococcus spp., preferably Strep suis, porcine cytomegalovirus, porcine herpesvirus, swine influenza virus, swinepox virus, Toxoplasma gondii, vesicular stomatitis virus and / or swine exanthema virus.

[0031] The vaccine composition of the present invention may be a liquid formulation, such as a preparation for parenteral, subcutaneous, intradermal, intramuscular, or intravenous administration (e.g., injectable administration), such as an aqueous solution, water-in-oil or oil-in-water emulsion, syrup, elixir, tincture, sterile suspension, or emulsion. Such formulations are known in the art and are typically prepared by dissolving the antigen and other typical additives in a suitable carrier or solvent system. Liquid formulations may also include suspensions and emulsions containing suspending or emulsifying agents.

[0032] Dosing regimen The present invention provides an improved PCV vaccination regimen for pigs, essentially comprising one administration to sows at weaning and one administration to piglets at 3-6 weeks of age. In a typical embodiment, sows and their piglets are treated essentially on the same day at weaning. Such vaccination effectively protects piglets without the need for MDA assessment. Such a vaccination regimen effectively protects sows until the next weaning. Such vaccination ensures effective vaccination of the next generation of piglets with a single vaccination at 3-6 weeks of age.

[0033] The route of administration can be transdermal via mucosal administration, or other parenteral routes (intradermal, intramuscular, subcutaneous, intravenous, or intraperitoneal). The vaccine of the present invention can be conveniently administered intranasally, transdermally (i.e., applied to or on the skin surface for systemic absorption), parenterally, ocularly, etc. Parenteral administration routes include, but are not limited to, intramuscular, intravenous, intraperitoneal administration, etc. Intramuscular administration is preferred.

[0034] The vaccines of the present invention can be administered as a single dose. Furthermore, the vaccines of the present invention can be administered alone or simultaneously or sequentially with one or more additional compositions, such as, for example, other porcine immunogenic or vaccine compositions.

[0035] In practice, the exact amount required for an immunologically effective dose may vary from subject to subject, depending on factors such as the subject's age and general condition, the nature of the formulation, and the mode of administration. An appropriate "effective amount" can be determined by one of ordinary skill in the art using only routine experimentation. For example, methods are known in the art for determining or titrating appropriate vaccine dosages to find the minimum effective dose based on the non-human animal subject's weight, vaccine concentration, and other typical factors. In a typical embodiment, the vaccine comprises a single dose of 0.5 to 5 ml. Most preferably, sows are administered between 2 and 4 ml, and piglets are administered between 0.5 and 3 ml.

[0036] In certain embodiments, the present invention relates to a method for controlling PCV infection or disease in a herd. Controlling PCV infection or disease refers to, inter alia, preventing, reducing, or limiting PCV infection and associated disease, preventing, reducing, or limiting the spread of PCV in a herd, preventing, reducing, or limiting the occurrence or severity of PCV-associated disease, or reducing PCV viral load.

[0037] PCV2 vaccination In a preferred embodiment, the present invention is used to vaccinate pigs against PCV2 or to control PCV2 infection or disease. Thus, the present invention uses a PCV2 vaccine.

[0038] Currently developed PCV2 vaccines, such as Circovac® (Ceva), Ingelvac®, CircoFLEX (Boehringer Ingelheim Vetmedica), and Suvaxyn®, are either inactivated PCV2 vaccines or subunit vaccines. PCV2 subunit vaccines typically use purified recombinant PCV2a capsid protein produced by recombinant expression of the ORF2 gene of PCV2a. In this regard, the protein encoded by ORF2 of PCV2 isolate Imp 1011 is reported in EP 1741785. The protein encoded by ORF2 of PCV2 isolate PCV2Rm is reported in WO 2010 / 061000. The protein encoded by ORF2 of PCV2 isolate 412 is reported in EP 1816200. Other proteins encoded by ORF2 of further PCV2 isolates are reported in EP 1036180 or EP 2225367. Improved synthetic ORF2-type proteins are described in WO2013 / 030320 and WO2014 / 167060.

[0039] In a specific embodiment, the present invention uses a PCV2 vaccine that is an inactivated PCV2 vaccine. The vaccine can include any inactivated PCV2 strain, such as inactivated PCV2a, inactivated PCV2b, or inactivated PCV2d. A specific example is Circovac.

[0040] In another specific embodiment, the present invention utilizes a PCV2 vaccine that is a subunit vaccine comprising (or expressing) a PCV2 ORF2 polypeptide or a fragment thereof. In a specific embodiment, the ORF2 is selected from ORF2 of PCV2 isolate Imp1011, PCV2Rm, or 412, or an ORF2 having at least 80% sequence identity to such proteins, or an immunogenic fragment thereof comprising at least 10, 15, or more preferably at least 20 consecutive amino acid residues thereof.

[0041] Additional aspects and advantages of the present invention are disclosed in the following Examples section which describes the claimed invention. [Brief explanation of the drawings]

[0042] [Figure 1] 1 shows the immunization protocol for Clinical Trial B. [Figure 2] PCV2 IgG levels in sows are shown. [Figure 3] PCV2 IgG levels in piglets are shown. [Example]

[0043] Clinical Trial A Study design The study will be carried out in Italian pig farms with a confirmed diagnosis of PCVD according to the criteria of the EU consortium on PCVD research. The study will be performed according to a randomized, controlled, and blinded design.

[0044] Pre-enrollment of sows: Blood samples were taken from 150 sows during mid-gestation for the detection of ELISA antibodies against PCV2 and for the calculation of S / P values. Three groups of 50 sows each were organized and assigned to three different groups equalized according to a) mean parity; b) mean S / P value.

[0045] Sow Enrolment: Three groups of 50 sows will be treated as follows: Group A: Vaccinate at weaning (V1). Group B: vaccinated only 5 weeks and 3 weeks before the expected delivery date (V2). Group C: Non-vaccinated / control (NV)

[0046] One week before the expected farrowing date, blood samples are taken from all sows.

[0047] Piglet enrollment: Approximately 900 suckling piglets of 3 weeks of age (minimum 100 piglets per study group) will be enrolled in the study.

[0048] Upon enrollment in the study, piglets from the above sows (groups A, B, and C) will be individually identified by ear tagging, 40% of the animals will be weighed, and 20% will be bled at each sampling.

[0049] Piglets are then randomly assigned to one of three study groups within each litter. All piglets receive an intramuscular injection of CIRCOVAC (left). One group (A) is 3 weeks old, and the other group (B) is 6 weeks old. One group (C) is injected with saline (placebo) and is maintained as a negative control. [Table 1]

[0050] Piglets are weighed at entry, at the end of the nursery period, and at 6 months of age. Carcass weights are recorded at slaughter, if possible. Individual treatments administered to piglets are recorded as a measure of morbidity. A post-mortem examination is performed on each dead piglet to determine the cause of death, unless the cause is clear and not related to PCV2 (e.g., piglet crushed by the sow, broken leg, etc.).

[0051] As key parameters of the effectiveness of the vaccination scheme, mean daily weight gain, morbidity and mortality, and PCV2 viremia will be compared between the study groups.

[0052] Blood samples are collected from 20 piglets per group according to the timing shown in Table 1. Weighing times are also shown in Table 1.

[0053] All piglets will be monitored for vaccination reactions immediately after vaccination, at day 1, at week 1, and weekly until all reactions have resolved. [Table 2]

[0054] Test Products Investigated items Product: CIRCOVAC (CEVA) Composition / potency: Inactivated PCV2 vaccine Packaged in 100ml PET vials

[0055] animal 900 healthy piglets (100 in each group) approximately 3 weeks old will be included in the study. All piglets come from sows that were vaccinated as young piglets and boosted at their first breeding. The sows will be vaccinated at weaning from the previous lactation or 5 and 3 weeks before farrowing, according to the scheme indicated in point 2 (two groups of sows).

[0056] livestock Study animals (all groups mixed) are housed on the farm according to standards.

[0057] Research animals are maintained according to standards on the farm.

[0058] Blinding The study will be blinded, and vaccine vials will be identified only by label codes.

[0059] treatment ·Dose: Sow 2ml, piglet 0.5ml Route: By intramuscular injection Injection site: left side of neck Group A: 3-week-old Group B: 6-week-old Unvaccinated Group C

[0060] Evaluation of effectiveness The following parameters are used to evaluate the effectiveness of various vaccination protocols: i. Average daily weight gain (ADWG) ii. Mortality and causes of death, including animals culled iii. Morbidity (individual procedures / injections) iv. Percentage of PCR-positive animals for PCV2 v. PCV2 viral load from blood samples (Q-PCR) vi. Serological profiling of PRRSV and M hyo vii. Necropsy and microbiological examination of animals that died naturally and animals that were humanely euthanized viii. Lung lesion scoring at the slaughterhouse

[0061] The kinetics of humoral and cellular immune responses will be measured by ELISA serology (INGENASA) and ELISpot for IFN-γ SC, respectively. These studies will be performed on stored blood samples and PBMCs.

[0062] Additionally, antibody titers against PCV2 will be determined to assess the level of maternal antibodies and immune response to vaccination and the timing of field infection.

[0063] PCV2 viral load (Q-PCR) from blood samples. Q-PCR for PCV2 by standard procedures.

[0064] serology Serological responses to vaccination and infection will be measured using commercially available kits [IDEXX laboratories (PRRS and Mhyo) and INGENASA (PCV2) IgM+IgG].

[0065] After clotting, the serum is divided into two serum tubes and the samples are stored at ≦−18° C. until analysis.

[0066] Cell-mediated immune response The cellular immune response is measured by ELISpot assay to determine IFN-γ SC.

[0067] IFN-γ ELISpot assay. Peripheral blood mononuclear cells (PBMCs) are separated by a density gradient of Histopaque-1077® solution with a centrifugation step of 30 minutes at 420×g (1800 rpm).

[0068] Finally, PBMCs were collected by aspiration, resuspended in RPMI-1640 medium, and seeded at a density of 200,000 cells / 200 μl RPMI-1640 (supplemented with 10% FCS) onto 96-well plates coated with anti-IFN-γ monoclonal antibody (P2G10-BD Pharmingen). In vitro stimulation was performed with PCV2 antigen (virus: 0.1-1 MOI; order: μg / ml) for at least 20 hours. IFN-γ secretion by PBMCs was detected using anti-IFN-γ (P2C11-BD Pharmingen) biotin-conjugated monoclonal antibody, alkaline phosphatase-conjugated secondary antibody (Vector), and NBT / BCIP developing substrate solution (BioRad). The reaction was visualized as a blue spot by precipitation of the substrate where cells secreted IFN-γ using an AID® ELISpot Reader.

[0069] Lung lesions at the slaughterhouse At the slaughterhouse, lung lesions are checked according to the Madec grid and the SPES grid.

[0070] The results of these experiments confirm the clinical protection (vaccine efficacy) conferred by such a new vaccination regimen and that it can provide sufficient protection with a single dose of vaccine, without the need to evaluate passively acquired immunity derived from gilts and sows.

[0071] Clinical Trial B Three groups of gilts (10 pigs each) were vaccinated with Circovac (2 mL) according to the vaccination regimen shown in the table below. [Table 3]

[0072] To assess viremia and immune responses, 12 blood samples were collected from each animal throughout the study on the dates indicated by the arrows in Figure 1. The mean values ​​of anti-PCV2 IgG in sows and piglets are shown in Figures 2 and 3.

[0073] The results in Figure 2 clearly show that vaccination induced the production of specific antibodies in the sows. It is surprising that the titers were more uniform in Group B sows than in Group A. Group A sows consistently showed high titers before each farrowing in response to the pre-farrowing booster vaccination. We did not observe these peaks in Group B sows. This means that Group B sows did not have as high a concentration of antibodies just before their litters began to receive colostrum, which subsequently appeared as MDA in the piglets' blood.

[0074] Similarly, Figure 3 shows that piglets born to sows in group A exhibit much higher antibody titers at 1 and 3 weeks of age. Furthermore, a very high variation in titers is observed within group A. In contrast, piglets born to sow B (first litter) with a first parity exhibit moderate titers at 1 week and relatively low titers at 3 weeks, while piglets born to sow B (second litter) with a second parity exhibit very high titers at 1 week (not interfering, as they are not vaccinated at this age) and moderate titers at 3 weeks upon vaccination. Furthermore, titers at 3 weeks are much more homogeneous than those in group A and also in group C (control, unvaccinated sows). Some piglets in group C have high titers, likely due to their mothers being infected and producing post-infection antibodies. Their titers are much more variable than those in group B.

[0075] Therefore, the immune profile of Group B is advantageous because we wanted to achieve a uniform level of immune status in the sows to protect them and also an adequate (but not too high) uniform immune status (level of MDA) in the piglets to protect them without causing interference with vaccination.

[0076] Thus, the results of these experiments further confirm the clinical protection conferred by such new vaccination regimens (vaccine efficacy) and that a single dose of vaccine can provide sufficient protection without the need to evaluate passively acquired immunity derived from gilts and sows.

Claims

1. 1. A porcine circovirus type 2 (PCV2) vaccine for use in a method for controlling PCV2 infection or disease in a swine herd, the method comprising vaccinating sows and their piglets against PCV2, wherein (i) the sows are vaccinated at the time of weaning their piglets, and (ii) the piglets are vaccinated at 3 to 6 weeks of age.

2. 1. A PCV2 vaccine for use in vaccinating pigs against PCV2 infection or disease, comprising vaccinating sows and their piglets, wherein (i) the sows are vaccinated against PCV2 at the time of weaning their piglets, and (ii) the piglets are vaccinated against PCV2 at 3 to 6 weeks of age.

3. 1. A PCV2 vaccine for use in inducing protective anti-PCV2 immunity in pigs, comprising vaccinating sows and their piglets against PCV2, wherein (i) the sows are vaccinated against PCV2 at the time of weaning their piglets, and (ii) the piglets are vaccinated against PCV2 at 3 to 6 weeks of age.

4. The PCV2 vaccine for use according to any one of claims 1 to 3, comprising vaccinating piglets at 3 weeks of age.

5. The PCV2 vaccine for use according to any one of claims 1 to 3, comprising vaccinating piglets at 6 weeks of age.

6. 2. The PCV2 vaccine for use according to claim 1, comprising vaccinating sows and their piglets essentially on the same day at the time of weaning.

7. The PCV2 vaccine for use according to any one of claims 1 to 6, wherein the vaccination of the sows and piglets is carried out with an inactivated PCV2 vaccine.

8. The PCV2 vaccine for use according to any one of claims 1 to 7, wherein the vaccination of the sows and piglets comprises a single injection of the PCV2 vaccine.

9. 2. The PCV2 vaccine for use according to claim 1, wherein the vaccination of the sows and piglets comprises a single intramuscular injection of the PCV2 vaccine.

10. 2. The PCV2 vaccine for use according to claim 1, wherein the sows are vaccinated at each weaning of their piglets.

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