1.
Open Session of the EuFMD - Cascais –Portugal 26-28 October 2016
THE SEROLOGICAL RESPONSE INDUCED BY
INACTIVATED FMD VACCINE IN ISRAEL –
CLINICAL TRIALS IN A DAIRY FARM
Ehud Elnekave, Aldo Dekker, Phaedra Eble, Froukje van
Hemert-Kluitenberg, Boris Gelman, Nick Storm, Eyal Klement

2.
Before we start…
This Presentation is based
on the fruits of a PhD
performed by Dr. Ehud
Elnekave
Israeli Kimron Veterinary institute
Boris Gelman
Nick Storm
CVI, The Netherlands
Aldo Dekker
Phaedra Eble
Froukje van Hemert-Kluitenberg

3.
• Commercial vaccine - Merial®
• High potency dose (PD50≥6)
• Same vaccine is used for routine and emergency
vaccination
• Cattle – Trivalent vaccine (O, A and ASIA-1)
• 1st vaccination between 2-3 months of age
• 2nd vaccination up to 3 months later
• Annual vaccination
FMD vaccination in Israel

4.
Vaccine effectiveness in Cattle –
prior experience from Israel
• Dairy cattle are rarely affected during FMD outbreaks
• When they are affected only young animals show
clinical disease
• Young animals are (up to two years old) are only
partially protected from clinical morbidity despite
multiple vaccinations (Elnekave et al. 2013)
• Emergency vaccination is highly effective in
prevention of clinical and subclinical morbidity (Elnekave
et al. 2013)
Elnekave E, Li Y, Zamir L, Even-Tov B, Hamblin P, Gelman B, Hammond J, Klement E. (2013) The field effectiveness of
routine and emergency vaccination with an inactivated vaccine against foot and mouth disease. Vaccine. 31:879-85

5.
Hypothesis and Questions
• It takes more than a certain number of vaccinations to elicit a stable immune
response
• Age of initial vaccination influences not only the immune response at the initial
phase but also at the later stages
• What is the number of vaccinations needed to elicit a stable immune response?
• What is the ideal age for administration of first vaccination and what is the best
vaccination schedule to elicit a good immunological coverage during the first two
years of life?

6.
Research aims
Estimation of the long term antibody dynamics:
1. Routinely vaccinated cows and heifers of different
vaccination statuses
2. Non vaccinated calves –
•After ingestion of colostrum
•After vaccination in different ages and different
levels of maternal immunity

7.
Vaccination trial
Cows Heifers
4 vac.
4554
≥6
vac.
1 vac.2 vac.3 vac.5 vac.
Trivalent –
day 0
# of animals
0 1 2 4 6 8 12 16 24 36 51 55 77 102 weeks
TrivalentTrivalent
Antibody dynamics in response to vaccination
Study design

8.
Antibody dynamics in response to vaccination
•Groups vaccinated less
than 3 times:
- Rapid increase in the antibody
titers after vaccination
- Followed by quite rapid decrease
•Groups vaccinated 4
times or more:
- No reaction to vaccine
administration
- Consistent antibody levels
Vaccine serotype O-4625

9.
Average neutralizing antibody titer before
vaccination in the 1st (a) and the 2nd (b) years

10.
Proportion of animals with titers higher
than cut of log10=2 during the 1st year

11.
The long term effect of age and maternally derived
antibodies on the serological response in young dairy calves

12.
Maternal Antibody Decay
Half-life=22 days

13.
Antibody dynamics in response to vaccination

14.
Average neutralizing antibody titers (NAT) above cut-off
titer of 2.0 between the age of six months and 1.5 years

15.
Percentage of time over any cutoff

16.
Conclusions
• Five vaccine doses provide long lasting immunity
• Given the fact that emergency vaccination is always warranted
during an outbreak, the effectiveness of vaccinating after 5
vaccinations should be re-assessed
• Vaccination of calves prior to the age of three months does not
elicit good AB response not just after vaccination but also
impairs the entire immunological response later on.