Viral infections of the equine respiratory tract are a veterinary challenge. They occur frequently and result in major economic loss to the horse industry. Currently available vaccines are not completely effective in controlling respiratory diseases, and the growth in international travel contributes to their spread.

The most common and important causes of viral respiratory disease in the horse are equine influenza and equine herpesviruses. Both were discussed extensively during the eighth International Conference on Equine Infectious Diseases, held in Dubai in March. In addition, the issues of disease control raised by a more internationally mobile horse population were addressed.

Vaccine effectiveness was among the hot topics in the equine influenza presentations. Problems include the short duration of protection that vaccination provides and variations in the potency of the different products. Some contain viral strains that are no longer epidemiologically relevant.

It was suggested that more studies to identify the best vaccine and a greater effort to make the information public (“naming names”) would be beneficial. Minimum standards must be met to get a vaccine licensed in the United States. However, because the government does not release the data that is turned in by the pharmaceutical companies seeking vaccine approval, the main sources of information about vaccine effectiveness are independent research and the experiences of vaccine users