Mike Roof, PhDExecutive Director Bio R&D

Impact of PRRS vaccination on infectious load and implications for area control

Background – the PRRS “challenge”

3

Background – Tools to help control the PRRS challenge

• 2100 PRRS negative weaned pigs • 42 pens / room with 25 pigs/pen ≈ 1050 pigs/room • Divided by a wall with separated pits & attic•Biosecure entry system implemented for each room

Non-vaccinated controlRoom (North)

MLV vaccinatedRoom (South)

Shower &

officeLoading chute

•Objective of study was to quantify the effect of MLV vaccine on performance and measure wild-type virus (WTV) shedding in pigs vaccinated at weaning and challenged 4 weeks later.

S Dee, J Nerem, T Wetzell, J P Cano, and J Rustvold

Study design

MLV

NVC

-1 0 3 7 14 21 29 32 36 43 52 58 66 80 93 122 147 DPV

Arrival

Sorting Weigh

ID

Ingelvac® PRRS MLV

PRRSv IM inoculation 10% of pigs

» Serum (30 per room) & OF (6 per room) PCR & ELISA» 20-30’ bioaerosol 6 days / week at 8AM (Liquid cyclonic collector ®)

Liquid Cyclonic Aerosol Collector (Midwest

Microtek, SD)

Bioaerosol PCR-pos days and Ct values

DPV 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74

MLV   24 23 24 24   24                                               30   24 22   27                                                                              

NVC                                                 33   34 34 30     32 28 31 26 29 30 28   33 32     33   27 29   36   29 34 32 32                  

DPV 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100

101

102

103

104 105 106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

MLV                                                                                                                                                      

NVC                                                                                                                                                

MLV vaccinatio

n

1-18-2 inoculatio

n

Frequency of PRRSV detection in Air by PCR:All 118 days PI: MLV 4/118 (3.4%) air days vs. NVC 21/118 (17.8%) air daysFirst 40 days PI: MLV 4/40 (10%) air days vs. NVC 21/40 (52.5%) air days(McNemar’s test p-value < 0.0001)

Duration of air detection by PCR: MLV 6 DPI vs. NVC 36 DPI

Control

Group

Vaccine

Group

DD

DD

-29 5 0 3 8 36 70 95 118 DPI

Pig arrivalSorting

Weigh ID

1-18-2 challeng

e

ATP vaccinations

» Serum and Bioaerosol samples tested by RT-PCR

SlaughterWeigh

Therapeutic administration of Ingelvac PRRS® reduced PRRSV shedding in aerosol

PRRSV in aerosol  CONTROL VACCINATEDMean (RNA copies/mL) 4.3 x 108 a 4.5 x 108 a

95% conf interval2.6 x108 - 6.1 x 108 a 2.7 x 108 - 8.1 x 108 a

# pos days 31a 17b

last DPI positive 70 45# pos days (McNemar's test p-value 0.0004)

(Linhares et al., 2012)

Role of Vaccine for PRRS Control· Direct benefit – proven reduced clinical disease following wild type exposure in heterologous challenge studies

– Pig model - % lung lesions– Sow Model – reproductive performance

· Indirect benefit - Reduction of wt-virus sheddingMaintain uniform immunity

– Within and between populations– Reduce level of virus

• Direct and Indirect benefit-mitigate consequences of infection improving health and performance

• Vaccine Derived Immunity Matters

Role of Vaccine - Unanswered QuestionsWhat is the effect of challenge dose in vaccinated pigs?

1. What challenge dose of virulent PRRSV is required to cause infection and consequences of infection in a vaccinated animal?

– viremia, fever, reduced ADWG– How does vaccination impact the host PRRS status to various

dose exposures?

2. Is there a challenge dose where vaccination prevents consequences of infection?

– Does vaccine “blunt” or “shield” a pig from PRRS infection at any level?

– Aerosols, fomites, and transmission with lower levels of PRRS exposure (vs pig to pig)

– Applications to regional control programs

Study Design

Randomized, blinded vaccination-challenge study

Pigs used for the study were 3 wks of age and PRRSV naïve; confirmed PCR negative for PRRSV

Statistics• Results summarized via descriptive statistics

by day, challenge dose and group• For number days pyrexic and ADWG post-

challenge• P-value < 0.05 was used to indicate

statistical significance

Study Design

Group

No. InglevacPRRS® MLV

Vaccinated Pigs(2ml IM)

No. Non-vaccinat

edChalleng

e Control

Pigs

PRRSV SDSU-73Challeng

eDosage(Log10TCID50/ml)(2ml IN)

 Study

Termination

  Day 0 Day 0 Day 28 Day 701 10 10 4 logs

 2 10 10 3 logs3 10 10 2 logs4 10 10 1 log5 10 - None

Study Design

Parameter DayViremia PCR (+/-)

0, 7,14, 21, 28, 31, 33, 35, 38, 42, and weekly thereafter until day 70

Temperature (Pyrexia defined as a rectal temp > 40.0°C)

Day 27Daily for 14 days until Day 42

ADWG 0, 28, 70

Company Presentation 2013 Boehringer Ingelheim Animal Health 15

Results – Interpretation and Considerations

• Viremia is measured by PCR which was the most conservative evaluation and measure of vaccination impact.

• At high CT values that are PCR positive, we expect many of these samples would be virus isolation negative or very low levels of virus

• Current PCR results did not differentiate between Ingelvac and SDSU 73 and so data needs assessed by GROUP comparison of Ingelvac only vs Vacc/Exposed.

• Future opportunities that are being considered• Complete virus isolation• Assess via differential PCR

Results – Viremia 4log challenge

28 31 33 35 38 42 49 56 63 700%

20%

40%

60%

80%

100%

120%

Ingelvac PRRS® MLV (challenge)

Challenge Con-trol (non-vac-cinated)

Ingelvac PRRS® MLV (no challenge)

Days

% P

CR

Pos

itive

Figure 1. Percentage of viremic pigs per treatment group challenged with 4 logs

Reduction in post-challenge

viremia in vaccinates

Results – Viremia 2log challenge

Figure 2. Percentage of viremic pigs per treatment group challenged with 2 logs

28 31 33 35 38 42 49 56 63 700%

20%

40%

60%

80%

100%

120%

Ingelvac PRRS® MLV (challenge)

Challenge Control (non-vaccinated)Ingelvac PRRS® MLV (no challenge)

Days

% P

CR

Pos

itive

Vaccinates similar to

non-challenged

pigs

Results – Viremia following 2 log virus challenge

Average CT Values per Group Challenged w/ 2 Logs of Virus

Results – Pyrexia/Fever (40 C)

Mean Number Days Pyrexic Post-Challenge

Treatment Group

4 log challen

ge

3 log challen

ge

2 log challen

ge

1 log challeng

e

No challeng

eIngelvac PRRS®

MLV 4.41 4.21 1.01 1.41 1.8

Challenge Control(non-

vaccinated)11.2 8.8 10.0 6.0 -

Vaccinated groups had significant decrease in fever days and maintained lower average

temperature at all challenge doses

Vaccinates not

different than non-challenge

1 Statistically significant difference (P<0.05) in ADWG between Ingelvac PRRS®MLV and Challenge control groups based on model prediction

Measurable negative impact in non-vaccinated challenged groups at all challenge doses

Results – Average Daily Weight Gain

ADWG (lbs) Days 28-70

Treatment Group

4 log challen

ge

3 log challeng

e2 log

challenge1 log

challengeNo

challengeIngelvac

PRRS® MLV 1.41 1.291 1.701 1.641 1.67Challenge

Control(non-

vaccinated)1.18 1.06 1.15 1.23 -

1 Statistically significant difference (P<0.05) in ADWG between Ingelvac PRRS®MLV and Challenge control groups based on model prediction

Vaccinated groups higher ADWG compared to non-vaccinated at all

challenge doses

Measurable negative impact in

non-vaccinated groups at all

challenge doses

Vaccinates not

different than non-challenge

Role of Vaccine - Questions

Is there a challenge dose where vaccination prevents consequences of infection?· At a challenge of 2 logs or less, the

consequences of challenge in vaccinated pigs were similar to non-challenged pigs

· At all challenge doses, Ingelvac® PRRS MLV mitigated the consequences of infection as compared to challenge controls using the SDSU 73 wt virusADWG Viremia Temperature

↑ ↓ ↓

Take Home Messages

Relevance in the fieldFor pigs or populations of pigs at risk of challenge/infection Ingelvac PRRS® MLV derived immunity matters!- Direct benefit – Reduced clinical impact in vaccinated pigs following wt exposure - Indirect benefit

- Reduced viral load in pig and viral shedding (including aerosol)

- “blunting” of low level exposure to further reduce risk- May be important in area control programsMaintaining uniform immunity within and between populations can

reduce level of virus - Farm and flow, system-based, or ARC should continue a focused PRRS control programs utilizing vaccine.

- Don’t let your foot off the gas!- Beat virus down to a level of little consequence

Take Home Messages

Relevance in the field

At lower levels of challenge the consequences in vaccinated pigs were similar to non-

challenged pigsAt any level of challenge, Ingelvac PRRS MLV

demonstrated increase in ADWG and a decrease in temperature and viremia as

compared to the challenge controlsAt any level of challenge the impact in non-

vaccinated (non-immune) pigs is significant as measured by ADWG, viremia.

1.2.3.

Company Presentation 2013 Boehringer Ingelheim Animal Health 24

Narrowing the Funnel – incremental advances in PRRS control moving toward area control

PRRS “Cloud”

Immunity to Reduce Clinical Disease

Immunity/Management to Reduce PRRS Load

Pig Resistance to PRRS- Pig Genetics

-Reduce host infection (Immune)

- Area Control and reduced exposure

Company Presentation 2013 Boehringer Ingelheim Animal Health 25

Next Level of Questions and Challenges

• Impact of the challenge virus used and impact on the results!!?• VR2332 vs MN184 vs SDSU 73 vs 1-18-4……

• Study used Neg pigs:• Would the use of previously exposed animals that were

then vaccinated have an impact?• Would pigs vaccinated multiple times have different

results and raised the dose that could be “blunted”??

• Impact of vaccine timing and animal age!!?• Is the effect the same in a growing pig vs a sow/gilt?

INGELVAC® PRRS

Mitigate Consequences + Generate Uniform Immunity + Reduce Circulating Virus

=Improved Health & Performance

Thank you!!!!Questions?

Company Presentation 2013 Boehringer Ingelheim Animal Health 27