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Efficacy of Sow PEDV Vaccination as Evaluated by Piglet Challenge

Meggan BandrickZoetis, VMRD, Global Biologics ResearchNA PRRSv SymposiumDecember, 2016

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Zoetis is committed to helping producers & veterinarians fight PEDv

PEDv Conditionally Licensed Vaccine* Zoetis received a USDA Conditional License

for a Porcine Epidemic Diarrhea Vaccine, Killed Virus in September, 2014. Inactivated whole-virus Contains all relevant immunizing antigens (S- and

M-proteins) Adjuvanted to help enhance immune response

Requirements for a Conditional License:

*This product license is conditional. Efficacy and potency studies are in progress.

Rapid Disease Onset

Lengthy PEDv shedding

Reasonable Expectation of Efficacy in the target population Full Safety Evaluation in the target population across geographic sites Purity testing Efficacy and potency studies ongoing

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Introduction and Objective

•Pigs are most susceptible to PEDV immediately following birth. – Severity of clinical signs decreases with age– An outbreak on a naïve farm results in 80% -100% mortality – The disease has become endemic in some farms

•Therefore, to reduce mortality due to PEDV, it is key to protect piglets immediately following birth.

•The objective of this study was to evaluate the efficacy of an experimental Porcine Epidemic Diarrhea Vaccine when administered to pregnant sows, with a PEDV challenge in newborn piglets.

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STUDY DESIGN

Sows (approximate 6 weeks pre-farrow), sourced from a farm free of PEDV, were allotted to two treatment groups using a completely randomized design

Sows were assigned to 1 of 10 rooms with each treatment being represented per room.

Study Design

Treatment N sows/ litters Description Dose Sow

Vaccination Piglet

Challenge Study

Conclusion

T01 - Placebo 10* Adjuvant Placebo

2 mLIM

5 and 2 weeks pre-

farrow

Virulent PEDv when all piglets per litter

were 1‑12 hrs of age

7 days post piglet

challenge (dpc)

T02 - Vaccinated 10 Experimental

PEDV Vaccine

In vivo procedures occurred according to state, national, or international regulations.

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Endpoints

Sows

Fecal sample: PEDV qPCRSerum sample: PEDV FFN• Pre and post vaccination

Piglets

Cause of mortality • Due to PEDV or not due to PEDvGastroenteritis scoreFecal sample: PEDV qPCR• At necropsy

*Personnel performing animal observations and lab assays were masked to the assignment of animals to each treatment.

RESULTS

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RESULTS: Sow Serology

• Sows were negative for PEDV FFN antibodies pre-treatment; T01 remained at baseline.

• Vaccination induced an increase in least squares mean (LSM) PEDV FFN antibodies in T02 sows.

• T02 sows had significantly greater FFN responses than T01 sows.

Sow Serology (FFN) on Day 28 (7 days post 2nd vaccination)

Trt N Back-transformed least squares mean SE Range

Lower 95% confidence

bound

Upper 95% confidence

boundT01 –

Placebo 10 10.0 1.1 10 to 10 7.8 12.8

T02 – Vaccinated 10 52.8 5.7 20 to 80 41.3 67.4

Series10

10

20

30

40

50

60

T01 - Adjuvant placebo T02 - Experimental PEDV vaccine

PED

V FF

N A

ntib

odie

s

P ≤ 0.0001

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RESULTS: Litter Mortality due to PEDV

• Less piglets from vaccinated litters died due to PEDV compared to piglets from non-vaccinated litters

Trt

Summary of Least Squares Means Contrast vs T01

N % Mortality1 SE2

Mitigated Fraction Estimate

95% Bootstrap

P-valueLower Limit

Upper Limit

T01 – Placebo 10 100 0        

T02 – Vaccinate 10 40.5 15.1 0.70 0.400 1.00 0.0029

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Litter Mortality due to PEDV

p=0.0029

Of the 10 T01 litters (placebo), no litters/piglets completed the study; the last pig was removed on 5 dpc.

Of the 10 T02 litters (vaccinate), 7 litters had piglets that completed the study.

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RESULTS: PEDV Fecal Shedding in Piglets

•Piglets in T02 (vaccinate) shed significantly less PEDV in their feces compared to piglets in T01 (placebo).

PEDV (copy number/5uL feces) in Fecal Swabs Collected at Necropsy

Trt N Back-transformed least squares mean SEM Range Lower 95% CI Upper 95% CI

T01 – Placebo 94 811,136 743,826 2,356.67 to

37,266,666.67 107,102 6,140,000

T02 – Vaccinate 78 27,124 26,907 0 to

18,000,000 3,276.6 224,476

10,000

100,000

1,000,000

T01 - Adjuvant placebo T02 - Experimental PEDV vaccine

PED

V co

py n

umbe

r/5uL

fece

s (b

ackt

rans

form

ed le

ast s

quar

es

mea

m)

p=0.026

CONCLUSIONS

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CONCLUSIONS

Vaccination resulted in PEDV FFN responses

Vaccination resulted in significantly less mortality and fecal shedding in litters of vaccinated sows compared to control sows. Therefore, under the conditions of this study, the experimental

Porcine Epidemic Diarrhea Vaccine is efficacious.

The PEDV vaccine is a tool to help reduce neonatal mortality