Recently improved modified live vaccines for influenza and strangles. These vaccines appear to be both more efficacious and safer. Equine veterinarians and horsemen are not used to giving these vaccines. Not only is the administration unique but handling of these vaccines far more critical than the relatively tough killed vaccines we are used to. This article covers storage, handling, and administration of these improved vaccines.

The following useful tips for administration of intranasal vaccines to horses were developed by Robert E. Holland, DVM, PhD, and Thomas M. Chambers, PhD, for use with intranasal vaccines in general.

Prepare the vaccine following the package instructions from its manufacturer and using the applicator provided. Be certain to note the specific loading instructions, as some manufacturers may direct the vaccine be drawn up differently. An extremely helpful tip is to use a Luer-lock syringe for the administration of these vaccines. Non–Luer-Lok syringes can come loose and be clumsy and dangerous. Run your hand over the horse's nose a couple of times to see how sensitive the horse's nares are to manipulation. Agitation at this stage can be an excellent indicator that the horse will need some further restraint, such as a humane twitch.

Hold the vaccine syringe in your left hand, and stand on the left side of the horse. Hold the delivery device by the syringe, just below the Luer lock mechanism. Place your right hand on the horse's face just above the level of the nostrils. Place your right thumb just on top of the horse's left nostril opening. Use your thumb to keep the nostril wide while inserting the applicator. Use a smooth even motion to insert the applicator into the ventral nasal meatus. Spray the vaccine using one steady motion of the syringe plunger, and not too fast. It should be given approximately over a 1second time frame. Smoothly pull the device straight out of the horse's nose. Hold the horse's head slightly higher than parallel to the ground for 30 seconds. This helps coat the mucosal surfaces and reduces the potential for some of the vaccine to drip out of the nose. Sometimes a few drops will fall out and that appears not to interfere with the effectiveness of the vaccine. Also, it is common to see a little residue of the vaccine solution still in the nasal applicator device. This is normal and does not interfere with the vaccine effectiveness if most of the vaccine was delivered correctly.

Following are some do's and don'ts to remember for intranasal vaccine administration.