Intradermal needle-free injection prevents African Swine Fever transmission, while intramuscular needle injection does not

Field Evaluation of a Ready-to-Use Porcine Circovirus Type 2 and Mycoplasma hyopneumoniae Vaccine in Naturally Infected Farms in Taiwan

Porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae (MHP) are both important and common pathogens in the pig industry. Both pathogens are major contributors to the porcine respiratory disease complex and serve to potentiate other bacterial infections such as Actinobacillus pleuropneumonia. This study aims to evaluate the efficacy of a ready-to-use bivalent PCV2 and MHP vaccine in the field under naturally PCV2-infected farms against existing monovalent options. We evaluated PCV2 viremia, PCV2 antibodies, and lung lesion scores in slaughtered pigs in our study across four farms in Taiwan. Our results found that in two out of four farms, the piglets vaccinated with Porcilis® PCV M Hyo had superior whole-life PCV2 viremia reduction compared to the existing vaccination program on farms. In the lung lesion scoring, the Porcilis® PCV M Hyo group had significantly lower Actinobacillus pleuropneumonia-type lesions in pigs than in the competitor group in two out of three farms evaluated. In this field trial, Porcilis® PCV M Hyo proved to be efficacious in protecting piglets against both PCV2 viremia and the impact of MHP secondary infection, in the context of a reduction in viremia and reduced APP-like lesions found at slaughter.

The Evaluation of a Porcine Circovirus Type 2 (PCV2) Intradermal Vaccine Against a PCV2 Field Strain

Background/Objectives: Porcine circovirus type 2 (PCV2) has a major impact on swine productivity. Vaccines are used to aid in control and mitigate production losses. We investigated the protection provided by an intradermal PCV2 vaccine against a field strain in Taiwan. Methods: We conducted a safety and efficacy study. In the safety study, four Specific Pathogen Free (SPF) piglets were enrolled in the study. One was selected as the control and left unvaccinated, one was selected to be intradermally vaccinated with five times the standard dose (1 mL, Porcilis® PCV ID), and the other two were vaccinated with two times the standard dose (0.4 mL, Porcilis® PCV ID). All animals were observed for 3 weeks for adverse events post-vaccination. In the efficacy study, twelve SPF pigs negative for the PCV2 antibody were randomly divided into two groups. The first group of six pigs was vaccinated (Porcilis PCV ID, 0.2 mL) intradermally at 3 weeks of age. The second group of six pigs was sham vaccinated with 0.2 mL of normal saline. At 7 weeks of age, all pigs were challenged with the PCV2 strain CYC08 (1 × 105 TCID50/mL) by nasal and intramuscular injection. Clinical monitoring of body temperature and mortality was conducted daily. At 11 weeks of age, all animals were sacrificed for histopathological analysis. Results: No adverse events were reported in the safety study. In the efficacy study, the vaccinated animals had statistically improved results in the following areas post-challenge: body temperature rise, viremia, virus shedding, mortality, tissue histopathological and microscopic scores. Conclusions: The study results support that a one-dose PCV2 vaccine administered intradermally with a needle-free injector is safe and provides protection when challenged with a field PCV2 strain.

Lineage 7 Porcine Reproductive and Respiratory Syndrome Vaccine Demonstrates Cross-Protection Against Lineage 1 and Lineage 3 Strains

Background/Objectives: Porcine reproductive and respiratory syndrome virus (PRRSV) has a major impact on swine productivity. Modified-live vaccines (MLVs) are used to aid in control. We investigated the cross-protection provided by a lineage 7 PRRSV MLV against a lineage 1 isolate under laboratory conditions and a lineage 3 challenge under field conditions in Taiwan. Methods: In the first study, thirty PRRS antibody-negative conventional piglets were vaccinated via the intramuscular (IM) or the intradermal (ID) route, with the control group receiving a placebo. Four weeks after immunization, all groups were challenged with a Taiwanese lineage 1 strain. The standard protocol for detection of reversion to virulence was applied to the vaccine strain in the second study, using sixteen specific pathogen-free piglets. In the third study, on an infected pig farm in Taiwan (lineage 3 strain), three hundred piglets were randomly selected and divided into three groups, each injected with either the PrimePac® PRRS vaccine via the IM or the ID route, or a placebo. Results: In the first study, both vaccinated groups demonstrated reduced viraemia compared to the control group. The second study demonstrated that the MLV strain was stable. In the third study, piglet mortality, average daily weight gain, and pig stunting rate were significantly improved in the vaccinated groups compared to the control group. Conclusions: PrimePac® PRRS is safe to use in the field in the face of a heterologous challenge, successfully providing cross-protection against contemporary lineage 1 and lineage 3 PRRSV strains from Taiwan.

Needle-free intradermal vaccination, an opportunity to improve commercial pig welfare

In-farm livestock production vaccinations are commonly delivered intramuscularly using needles. While there are alternative strategies these have been subject to little attention and limited commercialisation. One such alternative is needle-free vaccines and studies have focused on the immune response few have addressed the welfare implications. This study aims to compare the impact of intradermal needle-free vaccination and intramuscular injection in terms of the welfare of the piglets. A total of 179 piglets were divided into two treatments: intradermal needle-free delivery and intramuscular delivery of a vaccine. Measures of health and welfare included, vocalisations, behavioural observations, papule formation, and weight. Piglets vaccinated via the needle-free intradermal route vocalised less and displayed no significant behavioural differences but showed increased weight compared to piglets vaccinated intramuscularly. The use of a needle-free device to deliver a vaccine through an intradermal route revealed no adverse effects on piglet welfare and supports the use of alternative strategies to vaccinate livestock.

Intradermal vaccination with Porcilis® Begonia can clinically protect against fatal PRV challenge with the highly virulent ZJ01 field strain

Since pseudorabies (PR) re-emerged and rapidly spread in China at the end of 2011, researchers have focused on effective vaccine strategies to prevent and control pseudorabies virus (PRV) infection in pig herds. Due to the extensive application of an attenuated vaccine based on the Bartha-K61 strain isolated in Hungary in 1961 and the variation of the PRV strain, it has been suggested that traditional vaccines based on the Bartha-K61 strain offer only partial protection against variant strains. It was therefore evaluated whether the Porcilis® Begonia vaccine, which is based on the NIA-3 strain with deletions in the gE and TK genes, is efficacious against experimental infection with the virulent, contemporary Chinese PRV strain ZJ01. In this study, piglets were vaccinated with Porcilis® Begonia through either the intradermal (ID) route or the intramuscular (IM) route and subsequently challenged intranasally with strain ZJ01 at 4 weeks post-vaccination. An unvaccinated challenge group and an unvaccinated/nonchallenged group were also included in the study. All animals were monitored for 14 days after challenge. Vaccinated and negative control pigs stayed healthy during the study, while the unvaccinated control animals developed lesions associated with PRV ZJ01 challenge, and 44% of these pigs died before the end of the experiment. This study demonstrated that ID or IM vaccination of pigs with a vaccine based on the NIA-3 strain Porcilis® Begonia clinically protects against fatal PRV challenge with the ZJ01 strain.

Intradermal Vaccination against Influenza with a STING-Targeted Nanoparticle Combination Adjuvant Induces Superior Cross-Protective Humoral Immunity in Swine Compared with Intranasal and Intramuscular Immunization

The development of cross-protective vaccines against the zoonotic swine influenza A virus (swIAV), a potential pandemic-causing agent, continues to be an urgent global health concern. Commercially available vaccines provide suboptimal cross-protection against circulating subtypes of swIAV, which can lead to worldwide economic losses and poor zoonosis deterrence. The limited efficacy of current swIAV vaccines demands innovative strategies for the development of next-generation vaccines. Considering that intramuscular injection is the standard route of vaccine administration in both human and veterinary medicine, the exploration of alternative strategies, such as intradermal vaccination, presents a promising avenue for vaccinology. This investigation demonstrates the first evaluation of a direct comparison between a commercially available multivalent swIAV vaccine and monovalent whole inactivated H1N2 swine influenza vaccine, delivered by intradermal, intranasal, and intramuscular routes. The monovalent vaccines were adjuvanted with NanoST, a cationic phytoglycogen-based nanoparticle that is combined with the STING agonist ADU-S100. Upon heterologous challenge, intradermal vaccination generated a stronger cross-reactive nasal and serum antibody response in pigs compared with intranasal and intramuscular vaccination. Antibodies induced by intradermal immunization also had higher avidity compared with the other routes of vaccination. Bone marrow from intradermally and intramuscularly immunized pigs had both IgG and IgA virus-specific antibody-secreting cells. These studies reveal that NanoST is a promising adjuvant system for the intradermal administration of STING-targeted influenza vaccines.