Research into designing better BHV-1 and BVD vaccines is
likely to continue given the potential economic losses associated with
and BVDV infection in cattle. New vaccines may include needle-free
methods, effective single-shot vaccines that extend the duration of
memory while decreasing the number of adverse vaccine injection sites
reactions. The following are criteria for designing BHV-1 and BVDV
- Vaccines should be safe and
- Efficacy should be determined on the
ability to provide protection from viral challenge. Protection
includes: ability to neutralize virus, reduction in clinical disease,
reduced viral shedding, duration of immunity and sterile immunity. If
viral challenge is not available, vaccine efficacy should determined on
the ability to induce an appropriate immune response. In the case of
BHV-1 and BVDV, type-1 immune responses have been demonstrated to be
superior to type-2 immune responses for conferring protection. Mucosal
immunity is also necessary for maximal protection.
- Vaccines should be safe for use in
young calves, pregnant cows and cattle in poor health. At present,
there is considerable debate over the safety of modified live viruses.
DNA vaccination has been proposed as a safe alternative to vaccination
with live virus. DNA vaccines preferentially induce type-1 immune
responses and transfection of host cells translates into prolonged
exposure of antigen to the immune system (relative to subunit or killed
- A single administration should be
sufficient to induce protective and prolonged immunity. Decreasing the
frequency of vaccine administration reduces costs associated with
administration and record-keeping, decreases the risk of adverse
injection site reactions, adjuvant reactions and contamination of meat
- Vaccines should induce protective
immunity as early as possible in calves, as the greatest risk of
infection is during the neonatal period.
- Vaccines should have markers which
enable laboratory tests to distinguish between immune responses
resulting from virus exposure and immune responses resulting from
vaccination. This has significance
for eradication programs and international trade.
vaccines are not the most ideal design for
safe, cost-effective and efficient protection against BVD and BHV-1,
effectiveness can be manipulated by means already discussed in the BVD
and BHV-1 vaccination sections. The way of the future is in the hands
of subunit and DNA vaccines that have the potential to deliver
efficient, safe, and immunologically relevant protection.
- Vaccines should be economical to
produce, easily stored and accessible on a global basis.