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PreveNile

This page contains information on PreveNile for veterinary use.
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  • PreveNile Indications
  • Warnings and cautions for PreveNile
  • Direction and dosage information for PreveNile

PreveNile

This treatment applies to the following species:
Manufacturer: Intervet/Merck Animal Health

Equine Vaccine

WEST NILE VIRUS VACCINE

LIVE FLAVIVIRUS CHIMERA

PRODUCT DESCRIPTION: PreveNile™ contains a lyophilized Yellow Fever West Nile (YF-WN) chimera virus vaccine. The human vaccine yellow fever virus, YF-17D, was used as the backbone. The YF-17D strain is a highly effective, well-tolerated live, attenuated vaccine that has been used for over 60 years to immunize approximately 400 million people1. The YF-17D virus was modified using molecular technology to form a YF-WN chimera virus that expresses the PreMembrane and Envelope proteins of WNV. Following injection, limited replication of the YF-WN chimera virus allows expression of these proteins that stimulate a protective immune response in the horse.

PreveNile Indications

For the vaccination of healthy horses to prevent viremia and as an aid in the prevention of disease and encephalitis caused by West Nile virus infection.

SAFETY DATA: Studies have shown that the YF-WN chimera virus in PreveNile™ has limited to no replication in cells of mosquitoes or in the mosquito vectors of West Nile Virus or Yellow Fever Virus2. Studies of the YF-WN chimera virus in non-target animal species also show a lack of pathogenicity3. Safety studies have demonstrated that the vaccine virus is stable and does not revert to virulence, does not disseminate into the tissues of vaccinated horses, and is not shed by vaccinated horses following administrations. An overdose study, 10X the standard vaccine dose was administered to horses, no clinical signs were seen in any horses, nor was vaccine virus recovered from the plasma, nasal, oral, and rectal swabs or from tissues from these vaccinated horses. Transmission of vaccine virus to sentinel horses kept in contact with these vaccinated horses did not occur. In a large field safety study of 919 horses, PreveNile™ was demonstrated to be >99% reaction-free when administered to horses of various ages, breeds, and sex. Of the 919 horses vaccinated, 229 were 4 months of age or younger, and 302 were pregnant mares, including 17 mares in the first trimester of gestation, 11 mares in the second trimester of gestation and 274 mares in the third trimester of gestation. No post vaccinal adverse events were observed in any of the foals or mares. Studies to continue to evaluate safety in these mares through foaling are ongoing. The results of this study show the vaccine to be safe when used to vaccinate horses 4 months of age or older by the intramuscular route.

EFFICACY DATA: Immunogenicity: A challenge study was conducted to establish the immunogenicity of PreveNile™ vaccine. Twenty, 5-month-old male and female horses were vaccinated one time by the intramuscular route. Ten additional horses served as unvaccinated controls. At 28 days post-vaccination, vaccinated and unvaccinated control horses were challenged by the intrathecal route with virulent WNV. Horses were observed during the 28-day post-challenge period for fever and clinical signs of neurological disease, including change in mentation, paresis, fasciculation and ataxia/recumbency. Challenge of unvaccinated control horses with virulent WNV by the intrathecal route resulted in clinical signs of disease that were consistent with those observed in horses naturally infected with WNV under field conditions. Post-challenge, 10 of 10 unvaccinated control horses demonstrated moderate or severe signs of WNV for two or more consecutive days. Eight of the 10 horses demonstrated a severe overall health condition due to WNV infection such that euthanasia was warranted for humane reasons. One of the 20 vaccinates demonstrated moderate or severe signs of fasciculation and ataxia for two consecutive days post-challenge. Neural tissues were evaluated for histopathology for evidence of viral encephalitis. Very mild/mild encephalitis was detected in the vaccinated horse showing clinical signs. Moderate to severe encephalitis was detected in all 10 of the control horses. Following challenge, virulent WNV was not recovered from the plasma or swab samples from any vaccinated horse. Virulent WNV was recovered from 7 of 10 control horses during days 2, 3, and 4 post-challenge. (Table 1)

Table 1. WNV Challenge 28 Days after Vaccination

Treatment

Horses

*Signs

Temp

Death

Virus Isolation

Encephalitis

PreveNile

20

1

0

0

0

1§

Control

10

10

9

8

7

10!

* Change in mentation, paresis, fasciculation and ataxia/recumbency observed for two or more consecutive days. Not included were signs observed for less than two consecutive days that were very mild and transient and could go unnoticed.

§ Horse in the vaccinated group had only very mild/mild encephalitis on histopathology.

! Horses in the control group had moderate to severe encephalitis on histopathology.

T≥102.5°F

Statistically significant differences (P<0.05) between vaccinates and controls were found for body temperature, neurologic signs, death, virus isolation and histopathology.

Onset of Immunity: A 10-day onset of immunity challenge study was conducted using PreveNile™ vaccine. Six yearling male and female horses were vaccinated with a field dose of vaccine one time by the intramuscular route. Three additional horses served as unvaccinated controls. Horses were challenged by the intrathecal route with virulent WNV 10 days following vaccination. Horses were observed during the 21 day post-challenge period for fever and clinical signs of neurological disease, including change in mentation, paresis, fasciculation and ataxia/recumbency. Post-challenge at 10 days after vaccination, 3 of 3 unvaccinated control horses demonstrated moderate or severe signs of WNV for two or more consecutive days, such that euthanasia was warranted for humane reasons. One of the six vaccinates demonstrated severe signs of WNV for one day post-challenge such that euthanasia was warranted. Neural tissues were evaluated for histopathology for evidence of viral encephalitis. Moderate to severe encephalitis was detected in the vaccinated horse showing clinical signs and in all 3 control horses. Following challenge, virulent WNV was recovered from 2 of the vaccinated horses (1 showing clinical signs) and in all 3 control horses during days 2, 3, and 4 post-challenge (Table 2). Five of six yearling vaccinates receiving a field dose were not affected when challenged 10 days after vaccination.

Table 2. WNV Challenge 10 Days after Vaccination

Treatment

Horses

*Signs

Temp

Death

Virus Isolation

Encephalitis

PreveNile

6

1

2

1

2

1

Control

3

3

2

3

3

3

* Change in mentation, paresis, fasciculation and ataxia/recumbency.

T≥102.5°F

Duration of Immunity: A challenge study was conducted to establish the duration of immunity of PreveNile™ vaccine. Ten yearling male and female horses were vaccinated one time by the intramuscular route. Ten additional horses served as unvaccinated controls. Horses were held in strict isolation for 12 months following vaccination and then challenged by the intrathecal route with virulent WNV. Horses were observed during the 21 day post-challenge period for fever and clinical signs of neurological disease, including change in mentation, paresis, fasciculation and ataxia/recumbency. Post-challenge, at 1 year after vaccination, 8 of 10 unvaccinated control horses demonstrated moderate or severe signs of WNV for two or more consecutive days. Eight of the 10 control horses demonstrated a severe overall health condition due to WNV infection such that euthanasia was warranted for humane reasons. One of the 9 vaccinates demonstrated moderate or severe signs of fasciculation for three consecutive days post-challenge and moderate signs of change in mentation for one day. This vaccinate was not euthanized. Neural tissues were evaluated for histopathology for evidence of viral encephalitis. Histopathologic evidence of encephalitis was detected in 1 of 9 vaccinated horses. Moderate to severe encephalitis was detected in 8 of 10 of the control horses. Following challenge, virulent WNV was not recovered from the plasma samples from any vaccinated horse. Virulent WNV was recovered from 9 of 10 control horses during days 1, 2, 3, 4, and 5 post-challenge. (Table 3)

Table 3. WNV Challenge 1 Year after Vaccination

Treatment

Horses

*Signs

Temp

Death

Virus Isolation

Encephalitis

PreveNile

9§

1

0

0

0

1

Control

10

8

7

8

9

8

* Change in mentation, paresis, fasciculation and ataxia/recumbency observed for two or more consecutive days. Not included were signs observed for less than two consecutive days that were very mild and transient and could go unnoticed.

§ One vaccinated horse was removed from the study prior to challenge.

T≥102.5°F

The results of these studies demonstrate that the live YF-WN chimera virus in PreveNile™ provides protection against virulent WNV challenge in yearling aged horses or older for 1 year following vaccination with a single dose.

Directions For Use

Aseptically reconstitute the desiccated vaccine with the sterile diluent provided and administer 1 mL by the intramuscular route. Initial vaccination of healthy horses may be given as early as 5 months-of-age. For primary vaccination, administer a single dose only. Re-vaccinate annually with a single dose. For horses previously vaccinated against West Nile, administer a single dose only.

Precautions

1. Recommended storage temperature 35-45°F (2-7°C).

2. Swirl gently after reconstitution.

3. Use contents promptly once reconstituted.

4. Non-chemically sterilized needles and syringes should be used for administration of vaccine.

5. Administration of epinephrine may be indicated in the event of an anaphylactic reaction.

6. Contains gentamicin as a preservative.

7. Burn this container and all unused contents.

8. Only healthy animals should be vaccinated. Animals incubating any disease or animals stressed due to shipping, malnutrition, or parasitism may not achieve or maintain an adequate immune response.

9. Do not vaccinate within 21 days before slaughter.

10. This product is not hazardous when used according to directions supplied. A material safety data sheet (MSDS) is available upon request. This and any other consumer information can be obtained by calling Intervet’s Customer Service Department at 1-800-441-8272.

References

1 Monath TP. Yellow fever: an update. Lancet. 2001:1:11-20.

2 Johnson B.W. et al. Growth characteristics of the veterinary vaccine candidate ChimeriVax™ - West Nile (WN) virus in Aedes and Culex mosquitoes. Medical and Veterinary Entomology. 2003:17:235-243.

3 Monath TP. et al. West Nile Virus Vaccine. Current Drug Targets - Infectious Disorders. 2001:1:37-50.

SUPPLIED:

Code: 034955

10 vials (1 dose each) of lyophilized vaccine,

10 vials (1 mL) of sterile diluent.

91660101

91660102

Code: 042149

2 vials (5 doses each) of lyophilized vaccine,

2 vials (5 mL) of sterile diluent.

91660501

91660502

FOR USE IN ANIMALS ONLY

U.S. VETERINARY LICENSE NO. 165A

INTERVET INC., Millsboro, DE 19966

www.intervetusa.com

www.prevenile.com

1-800-441-8272

Rev. 916601

U.S. Patent Nos: 6,878,372 and 6,962,708

NAC No.: 10474641

INTERVET INC., MERCK ANIMAL HEALTH
556 MORRIS AVE., SUMMIT, NJ, 07901
Customer Service:   800-521-5767
Order Desk:   800-648-2118
Technical Service (Companion Animal):   800-224-5318
Technical Service (Livestock):   800-211-3573
Fax:   908-473-5560
Website:   www.merck-animal-health-usa.com
Every effort has been made to ensure the accuracy of the PreveNile information published above. However, it remains the responsibility of the readers to familiarize themselves with the product information contained on the US product label or package insert.

Copyright © 2014 North American Compendiums. Updated: 2014-07-28

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