Frequently Asked Questions
1-Will the vaccine be of benefit if there
is an active flu infection on the premises?
This has not been tested. In general, live virus
vaccines are thought to stimulate a more rapid immune response than
killed virus vaccines. In addition, the live virus stimulates non-specific
responses (such as interferon production) very quickly that could
also help reduce infection by a wild-type virus. The fact that Flu Avert® I.N. vaccine is administered intranasally, at the
most likely site of infection by a wild-type virus, makes it more
likely that these non-specific responses could reduce infection
by the wild-type virus. So it is theoretically possible that Flu Avert® I.N. vaccine could help in these situations.
If you use Flu Avert® I.N. vaccine during
an outbreak, it would be a good idea to collect a nasal swab from
each horse just before vaccination. Even though you will not know
if the horse is shedding virus before you vaccinate, the results
could help you explain to your client why the horse got sick after
vaccination, if that occurs.
2- Is it safe to use the vaccine in a horse
that may be infected with influenza
virus?
There is no scientific reason to think that using
Flu Avert® I.N. vaccine in a horse already
infected with influenza will increase the risk of disease for that
horse or other horses in contact with it. In 1994, Dr. Julius Youngner
and Dr. Patricia Whitaker-Dowling (University of Pittsburgh School
of Medicine) and others reported on a study1 in 27 adult
human volunteers. In that study, 13 people were given a mixture
of a cold-adapted human influenza vaccine virus and a wild-type
human influenza virus, with no indication of any untoward effect.
The data demonstrated that administration of cold-adapted influenza
A virus to humans at the time of wild-type virus infection is a
safe procedure.
3- What is the best strategy for controlling
influenza in horses?
There should be no question that the best strategy
is to routinely vaccinate all horses before they are at any risk
of exposure. Especially now that we know outbreaks are occurring,
vaccinating all horses with Flu Avert® I.N. vaccine ahead
of these outbreaks clearly offers the most effective prevention
strategy. In addition, primary immunity is established from a single
intranasal vaccination with Flu Avert® I.N. vaccine.
The ideal plan is to vaccinate the horse at least 2 weeks before
exposure.
It should be noted that in previous outbreaks in
Kentucky, New Jersey and New York, the horses that were previously
vaccinated with Flu Avert® I.N. vaccine were
reported as not getting sick and were performing. But if an influenza
outbreak has already occurred, vaccinating horses not yet showing
clinical signs during an outbreak may help, and there should be
no concern about safety.
1 Youngner JS, Treanor JJ, Betts RF, Whitaker-Dowling
P.: Effect of Simultaneous Administration of Cold-Adapted and Wild-Type
Influenza A Viruses on Experimental Wild-type Influenza Infection
in Humans. Journal of Clinical Microbiology. Mar. 1994, p.750-754
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