Evaluation of the efficacy of one dose
of autogenous MJPRRS vaccine in
nursery pigs
Dr. Mark Wagner, DVM
Fairmont Veterinary Clinic
Fairmont, MN
Purpose of study
• Gain a better understanding of the role and
efficacy of using the autogenous MJPRRS
vaccine in controlling or managing PRRS virus
Trial data to be presented
• Trial #1
– Vaccination of PRRS naïve pigs at 21 days of age
and challenge with field virus at 32 days post
vaccination
• Trial #2
– Similar repeat of trial #1, pigs challenged at 28
days post vaccination
• Trial #3
– Vaccination of PRRS viremic pigs at peak viremia
Trial design
• Challenge material
– Virulent field virus with a 1-18-2 RFLP
• Group D-4 under MJPRRS virus grouping system
• Preparation of virus material
– A 21 day old PRRS naïve pig inoculated with the
1-18-2 field virus
– Serum collected 5 days post inoculation and frozen
– An aliquot of serum inoculated on cell culture and
harvested 7 days later, then frozen
Trial design
• Analysis of challenge material
– Sequencing completed to confirm 1-18-2 virus
– Quantitative PRRS PCR’s completed along with
TCID50’s
Inoculum
material
Serum
Cell Culture
ORF6-copies
per ml
Calculated IVP’s
per ml
TCID50
109
2,341
102
1010
24,416
103
Trial design
• Challenge dose
– Trial #1
• 0.5ml IM plus 0.5ml IN (serum material = 100 viruses)
(culture material = 1,000 viruses)
– Trial #2
• 0.5ml IM plus 0.5ml IN (culture material = 1,000 viruses)
– Trial #3
• 0.05ml IM plus 0.5ml IN (serum material = 55 viruses)
Trial design
• Vaccination protocol
– Treatment group
• MJPRRS
– 2ml dose that included 10% extra adjuvant (final 20%)
• Mycoplasma
– 2ml dose
– Control groups
• Mycoplasma
– 2ml dose
Trial design
• Data collection included
– Body temperature
– Virus replication based on PRRS Q-PCR’s
– Mortality
– Average daily gain weight
PRRS virus replication data:
Data compiled for Trial #1, Trial #2,
and Trial #3
Summary PRRS virus replication in MJPRRS vaccinated compared
to non-vaccinated 21 day old PRRS naïve pigs when challenged to
a field virus at 53 and 49 days old (Trial #1 & #2 data)
Serum Challenged
Days Post
Challenge
Vaccinated
Culture Challenged
Non–Vaccinated
Non–Vaccinated
ORF6 copies*
IVP#
ORF6 copies
IVP
ORF6 copies
IVP
ORF6 copies
IVP
1.8 x 109
704
2.8 x 109
1,118
1.3 x 109
-------------9.3 x 108
674
----------367
2.2 x 109
--------------8.4 x 108
867
---------328
6.4 x 107
25
2.7 x 108
106
1.1 x 108
-------------4.2 x 107
44
----------16
2.1 x 108
--------------7.2 x 107
83
---------28
5.4 x 105
0.21
2.0 x 106
0.79
2.2 x 106
-------------5.1 x 106
0.88
----------1.9
1.4 x 106
--------------2.1 x 106
0.50
---------0.80
5
11
23
Vaccinated
* ORF6 Copies per ml by Quantitative PCR
# Infective Virus Particles calculated per ml based on Q-PCR
Summary of PRRS virus replication in 26 day old PRRS viremic
pigs vaccinated with MJPRRS vaccine at the peak of viremia
compared to non-vaccinated controls (Trial #3 data)
Serum Challenged  then
Vaccinated
IVP#
ORF6 Copies
3.5 x 109
1,355
3.3 x 109
1,144
5.2 x 109
2,079
5.6 x 109
2,215
3.5 x 108
103
1.2 x 109
488
1.8 x 108
55
5.5 x 108
123
ORF6 Copies*
5 Days post challenge
(Day of vaccination)
7 Days post challenge
(2 Days post vaccination)
14 Days post challenge
(7 Days post vaccination)
24 Days post challenge
(10 Days post vaccination)
Non-Vaccinated
* ORF6 Copies per ml by Quantitative PCR
# Infective Virus Particles calculated per ml based on Q-PCR
IVP
Average daily gain data:
Data compiled for Trial #1 and Trial #2
Summary of Average Daily Gain (ADG) performance in
MJPRRS vaccinated compared to non-vaccinated 21 day
old PRRS naïve pigs when challenged to a field strain of
PRRS at 53 days of age (Trial #1 data)
Day of
Day 1
Day 32 post arrival
Day 55 post arrival
Overall
Vaccination
Challenged*
Day 1-23 post challenge
Day 1-55 arrival
Weight (Ibs)
Average
Average
ADG
Average
ADG#
Vaccinated
14.5
36.5
0.71
54.0
0.76
0.74
NonVaccinated
16.0
32.5
0.53
53.0
0.89
0.68
ADG
* All pigs challenged with PRRSv at 32 days post arrival (53 days of age)
# ADG affected by mortality;
Vaccinated group, 1 of 22 dead
Non-vaccinated group, 4 of 22 dead
Summary of Average Daily Gain (ADG) performance in MJPRRS
vaccinated compared to non-vaccinated 21 day old PRRS naïve
pigs when challenged to a field strain of PRRS at 49 days of age
(Trial #2 data)
Day of
Day 1
Day 28 post
arrival
Day 40 post
arrival
Day 54 post
arrival
Overall
Vaccination
Challenged*
Day 1 – 11 post
challenge
Day 11 – 24 post
challenge
Day 1-54
arrival
Weight (Ibs)
Average#
Average
ADG
Average
ADG
Average
ADG
ADG
Vaccinated
13.7
31.2
0.62
34.2
0.27
49.0
1.14
0.74
Nonvaccinated
14.2
35.5
0.76
37.6
0.19
48.0
0.80
0.52
* All pigs challenged with PRRSv at 28 days post arrival (49 days of age)
Mortality data:
Data compiled for Trial #1, Trial #2,
and Trial #3
Summary of Mortality in MJPRRS vaccinated compared to nonvaccinated 21 day old pigs when challenged to a field strain of
PRRS at 53 or 49 days of age (Trial #1 and #2 data)
Trial #1
Challenge material
Serum
Culture
Treatment group
Mortality at 23 days post challenge
Non-Vaccinated
3 of 11 (27%)
Vaccinated
1 of 11 (9%)
Non-Vaccinated
1 of 11 (9%)
Vaccinated
0 of 11 (0%)
Overall mortality for non-vaccinated groups, 18.2%
Overall mortality for vaccinated groups, 4.5%
Trial # 2
Challenge material
Culture
Treatment group
Mortality at 23 days post challenge
Non-Vaccinated
0 of 16 (0%)
Vaccinated
0 of 16 (0%)
Summary of Mortality in 26 day old PRRS viremic pigs
vaccinated with MJPRRS vaccine at peak viremia compared to
non-vaccinated controls (Trial #3 data)
Trial # 3
Challenge material
Serum
Treatment group
Mortality at 10 days post vaccination*
Non-Vaccinated
3 of 12 (25%)
Vaccinated
2 of 12 (16%)
* 15 days post challenge
Summary (I)
• Virus Replication
– For trial #1, a statistical reduction in virus replication
shown between the MJPRRS vaccinates compared to
the non-vaccinates at days 5 and 11 post challenge
(p value = 0.04 and 0.0098, respectively)
– For trial #2, no statistical difference noted
– For trial #3, a statistical reduction in virus replication
during vaccination at peak viremia at day 7 and 10
post vaccination
(p value = 0.048 and 0.002, respectively)
Summary (II)
• Average Daily Gain (ADG)
– For trial #1, no statistical difference noted
Numerically: Vaccinates, Day 1-23 post challenge, 0.76
Non-Vaccinates, Day 1-23 post challenge, 0.89
 High mortality in non-vaccinates likely affected ADG
differences in calculation
– For trial #2, A statistical difference (p value = 0.026)
between MJPRRS vaccinated group vs. controls
during Day 1-24
Numerically: Vaccinates, Day 1-24 post challenge, 0.74
Non-Vaccinates, Day 1-24 post challenge, 0.52
Summary (III)
• Mortality
– For trial #1
• Vaccinates
= 1 of 22 (4.5%)
• Non Vaccinates = 4 of 22 (18%)
– For trial #2
• No mortality in either group
– For trial #3
• Vaccinates
= 2 of 12 (16%)
• Non Vaccinates = 3 of 12 (25%)
Conclusions
• Data demonstrated that PRRS naïve or viremic pigs
were able to respond to one dose of autogenous
MJPRRS vaccine with extra adjuvant.
• A reduction on virus replication was statistically
demonstrated (2 of 3 trials).
• A numerical improvement in ADG was demonstrated
(2 of 2 trials). A statistical difference noted also (1 of
2 trials).
• A numerical improvement in Mortality was
demonstrated (2 of 3 trials).
Thank you