Frequently Asked Questions
Q. Is there any equine rhinopneumonitis vaccine that protects against the neurological form of equine herpes?
A. No manufacturer in the United States has performed a study using currently available vaccines to know if they protect against this specific form of equine herpes. Therefore, any manufacturer who implies that their vaccine offers this kind of protection has no supporting data and is only speculating. Until specific studies have been performed and reviewed by USDA/APHIS, no one can be sure if their vaccine protects against the neurological form of herpes.
Q. Calvenza has multiple studies supporting efficacy and immunity. Other flu/rhino products have similar data to support them don't they?
A. Absolutely not. No other flu/rhino vaccine has as much third party data or as many six and twelve month challenge studies as does Calvenza. There is a difference between vaccines and it's been proven by multiple studies.
- Third party challenge study of three commercial killed vaccines1
- Influenza North American and Eurasian A2 cross-protection study2
- Influenza challenge study to demonstrate initial efficacy of two doses following two different administration protocols (IM/IM and IM/IN)2
- Six month duration of immunity study2
- Twelve month duration of immunity study2
- Two EHV-1 and two EHV-4 challenge studies3
Q. What makes Calvenza different from other influenza vaccines in the U.S.?
A. Calvenza incorporates a high antigen mass, flexible administration and a relevant Eurasian A2 influenza strain. These unique features, coupled with an effective adjuvant and a relevant North American A2 influenza strain, make this a very effective influenza vaccine.
Q. Why is a Eurasian Flu strain important in the United States?
A. Experts who survey equine influenza outbreaks around the world and make recommendations to manufacturers, have been recommending that North American influenza vaccines include a relevant Eurasian strain for years. Eurasian Flu isolates are the key to providing the broadest influenza protection possible. Given the fact that performance horses travel extensively, it is little wonder that Eurasian influenza isolates have been isolated in North America during the past decade. Calvenza is the only vaccine approved in the U.S. or Canada that contains both North American and Eurasian strains of influenza A2 viruses.
Q. Does Calvenza EHV protect mares from EHV-1 abortion?
A. Calvenza has been proven safe for use in pregnant mares and is labeled accordingly. We are aware that some veterinarians have been using Calvenza for prevention of abortion, however, this is an off-label use of the vaccine.
Q. Why give three initial doses of Calvenza?
A. Independent studies in recent years and experience with intensive vaccination protocols in Europe and elsewhere, have shown two-dose protocols to be ineffective in producing immune responses that are consistently effective and long lasting when using killed antigens. Current AAEP vaccination guidelines recommend using a three-dose initial series for all killed vaccines.
Q. Will I experience site reactions with Calvenza?
A. Calvenza enjoys a reputation for being very smooth. Field safety trials, as well as feedback from clinical usage, indicate that a very low incidence of site reactions can be expected when Calvenza is administered I.M.
Q. Can Calvenza be used to booster horses that have been on a regular vaccination schedule with another EIV/EHV vaccine?
A. With a high antigen mass and relevant North American A2 influenza strains, Calvenza should be an ideal vaccine to booster conventional EIV/EHV vaccines. However, the intramuscular route would be recommended for initial booster administrations following other manufacturer's vaccines. Also, the full advantages of Calvenza may not be realized until a series of Calvenza administrations have been completed.
Q. Why were six and twelve month duration of immunity studies performed on the EIV fraction of Calvenza?
A. Boehringer Ingelheim Vetmedica is a global manufacturer of veterinary products. Calvenza was developed to be a superior vaccine for use by veterinarians in the United States and other countries. Some of these countries require a higher standard of performance to achieve governmental approval. Calvenza can be used with confidence knowing these additional studies have been performed to demonstrate exceptional efficacy and longer immunity.
Q. Aren't all carbomer-based adjuvant systems the same?
A. No. Studies presented at the 2003 annual AAEP meeting clearly showed that vaccines incorporating properly formulated carbomerbased adjuvant systems produced higher antibody titers than vaccines containing other adjuvant systems. Calvenza outperformed other carbomer-based vaccines.1 If sufficient antigen mass is not present for the adjuvant to amplify, the immune response and overall vaccine performance will be compromised no matter what strains or adjuvants are involved.
Q. Will Calvenza protect with two initial doses?
A. Yes! Studies sponsored by Boehringer Ingelheim Vetmedica, as well as independent university studies, have demonstrated Calvenza's ability to protect horses effectively after two initial doses. However, challenge studies to demonstrate six and twelve month duration of immunity for EIV involved a third dose at six months following the initial two doses.
Q. Economic considerations sometimes make it difficult to convince clients to give three initial doses over such a short time period. What should be done in those situations?
A. We can only recommend that the approved label administration protocol be followed. However, post-license challenge studies for both Calvenza EIV and Calvenza EHV were conducted utilizing a protocol consisting of 2 doses four weeks apart with a third dose administered six months following the second dose. Calvenza vaccines proved very effective when administered in this fashion. This data is available for review by practitioners considering off-label administration schedules.
Q. How long does influenza immunity last with Calvenza?
A. Duration of immunity challenge studies were conducted by Dr. Jenny Mumford and colleagues at the Animal Health Trust in Newmarket, England. Six and twelve month post vaccination challenge studies resulted in vaccinates demonstrating a significant reduction of severity and incidence of clinical signs, as well as quantity and duration of viral shedding in vaccinates versus nonvaccinated controls following challenge with virulent EIV.
Q. I've heard that if a vaccine doesn't have the "latest" North American influenza strain that it's not effective. Is that true?
A. Virus strains are always a topic of conversation but are frequently misunderstood. The "strain game" is not as important as you might think. Most isolates identified in the United States in recent years show little evidence of relevant antigenic drift. Calvenza generates high levels of cross-reactive antibodies to a wide range of other relevant North American and Eurasian subtypes of EIV A2 viruses.2 In fact, Calvenza is the only vaccine approved in the United States or Canada that contains both North American and Eurasian strains of influenza A2 viruses as recommended by the Worldwide Equine Influenza Surveillance Panel.
Q. Does Calvenza provide effective protection against rhinopneumonitis (herpesvirus)?
A. Absolutely. Research leading to the original approval of Calvenza had to prove to the satisfaction of USDA/APHIS that it provides protection against both EHV-1 and EHV-4. That is why Calvenza is approved for both types of EHV and Boehringer Ingelheim Vetmedica is allowed to state this on the label indications. All four EHV challenge studies demonstrated the ability of Calvenza to reduce the signs of clinical disease and virus shedding in vaccinated horses following challenge as compared to non-vaccinated control horses. Calvenza clearly demonstrated effective cross-protection against EHV-4 based on challenge.3
- 1 Townsend, H.G., et al. 49th Annual Convention of the American Association of Equine Practitioners, 2003 Proceedings.
- 2 The Animal Health Trust, Newmarket, Suffolk England CB8 7UU
- 3 Summit Research, Inc.
