Pigs vaccinated with INGELVAC PRRS MLV had significantly higher post-challenge average daily weight gain compared to pigs vaccinated with PRRSGard.

Key Takeaways

 

• Pigs vaccinated with INGELVAC PRRS MLV demonstrated a significant improvement in average daily weight gain (ADWG) compared to the placebo group and pigs receiving PRRSGard.¹
• Pigs vaccinated with INGELVAC PRRS MLV had a significant reduction in viremia compared to pigs receiving the placebo and those vaccinated with PRRSGard.¹
• Both Ingelvac PRRS MLV and PRRSGard significantly reduced lung lesions compared to the placebo group.¹
• While both vaccines demonstrated efficacy in the face of a heterologous PRRS challenge, this study provides additional evidence that protection against porcine reproductive and respiratory syndrome virus (PRRSV) can’t be predicted by a vaccine’s lineage origin or its sequence similarities to field strains.^1,2

In 1994, Boehringer Ingelheim introduced INGELVAC PRRS MLV, a new, innovative swine vaccine to help the industry combat the costly effects of porcine reproductive and respiratory syndrome (PRRS). It has continued to be the leading modified-live PRRS vaccine for more than 25 years, having demonstrated its ability to provide heterologous protection against numerous wild-type PRRSV strains that differ from their parent strains in nucleotide sequence and lineage in multiple controlled experimental and field research studies.^2,3

To evaluate and compare the efficacy of INGELVAC PRRS MLV and PRRSGard against a heterologous PRRSV 1-7-4 challenge, Boehringer Ingelheim conducted a randomized, blinded challenge study.

In the study, pigs vaccinated with INGELVAC PRRS MLV had significantly higher post-challenge ADWG compared to controls and PRRSGard-vaccinated pigs, demonstrating the ability of INGELVAC PRRS MLV to provide leading protection against a relevant and contemporary lineage 1 PRRSV strain.¹

In addition, both INGELVAC PRRS MLV and PRRSGard demonstrated heterologous protection by significantly reducing lung lesions compared to the challenge control group that received a placebo.¹

Key Findings

 

• During the post-vaccination/pre-challenge phase of the study:
  • There was not a significant difference in ADWG between vaccinates, while a significantly higher ADWG was observed among vaccinates compared to pigs receiving the placebo; and
  • Pigs vaccinated with INGELVAC PRRS MLV showed no signs of negative performance impacts, demonstrating the vaccine’s ability to generate a robust, protective immune response and contribute to a safe, smooth start for growing pigs.

 

• During the challenge phase of the study:
  • Pigs vaccinated with INGELVAC PRRS MLV and PRRSGard had significantly reduced lung lesions compared to the placebo group;
  • Pigs vaccinated with INGELVAC PRRS MLV demonstrated a significant improvement in ADWG, while pigs receiving PRRSGard had no significant difference compared to controls; and
  • Pigs vaccinated with INGELVAC PRRS MLV had a significant reduction in viremia compared to pigs receiving the placebo, while the reduction of viremia in pigs vaccinated with PRRSGard was not significantly different compared to pigs receiving the placebo.

 

Study Objective 

 

The objective of the study was to evaluate the efficacy of INGELVAC PRRS MLV and PRRSGard in a respiratory challenge model with 3-week-old pigs, using a heterologous PRRSV 1-7-4 field strain.

Study Design

 

To begin, 108 PRRS-naïve, 3-week-old pigs were randomized into three groups, and intramuscularly administered INGELVAC PRRS MLV or PRRSGard according to their label directions, or given a placebo.

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The study included the following steps:

1. On Day 0 of the study, pigs were administered vaccines or a placebo.

2. On Day 27, pigs were challenged with a virulent 1-7-4 PRRSV strain administered intranasally and intramuscularly.

3. Serum samples and weights were collected periodically from Day 0 through Day 42.

   • Pigs were tested by serum polymerase chain reaction (PCR) at days 0, 7, 14, 21, 27, 29, 33, 36 and 42 for PRRSV.

4. On Day 42 (14 days post challenge), all pigs were necropsied, and lungs were scored for the presence of macroscopic lesions.

 

Study Results 

 

• As seen in Table 2, during the pre-challenge phase of the study, there was not a significant difference in ADWG between vaccinates, while a significantly higher ADWG was observed among vaccinates compared to pigs receiving the placebo. In the challenge phase of the study (Day 27 – Day 42), pigs vaccinated with INGELVAC PRRS MLV had significantly higher ADWG compared to the PRRSGard-vaccinated and placebo groups.¹
• As seen in Table 3, pigs vaccinated with INGELVAC PRRS MLV and PRRSGard had significantly reduced lung lesions compared to pigs receiving the placebo.¹
• Pigs vaccinated with INGELVAC PRRS MLV had a significant reduction in viremia compared to pigs receiving the placebo, while pigs vaccinated with PRRSGard did not show a significant difference in the reduction of viremia compared to pigs receiving the placebo.¹

 

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Conclusions

 

During the pre-challenge phase of this study, there were no significant differences in ADWG between the vaccinated groups.¹ 

In the challenge phase, pigs vaccinated with INGELVAC PRRS MLV demonstrated significantly higher ADWG compared to the placebo group and pigs vaccinated with PRRSGard.¹ In addition, pigs vaccinated with INGELVAC PRRS MLV and PRRSGard had significantly reduced lung lesions compared to the pigs receiving the placebo.¹

For almost 30 years, producers and veterinarians have relied on Boehringer Ingelheim as a partner in swine health to help combat PRRS. This study further demonstrates why INGELVAC PRRS MLV continues to be the leading PRRS vaccine.

 

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References

¹ Boehringer Ingelheim Animal Health USA Inc. Efficacy of PRRS prototype vaccines against a PRRSV 1-7-4 isolate challenge in conventional 3-week-old pigs. Data on File. Study 2020409.

² Patterson A, et al. Efficacy of Ingelvac PRRS modified live virus vaccine against heterologous PRRSV challenges. J Vaccines Vaccin 2019;10:407.

³ Patterson A, Victoria J, Jordan D, et al. Modified-live PRRSV vaccination is efficacious following challenge with eight genetically diverse PRRSV isolates, in Proceedings. Allen D. Leman Swine Conf. 2013.

 

INGELVAC PRRS^® is registered trademark of Boehringer Ingelheim Vetmedica GmbH, used under license. All other trademarks are property of their respective owner. ©2022 Boehringer Ingelheim Animal Health USA Inc., Duluth, GA. All Rights Reserved. 
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