Please be aware that when you compete at a USEF recognized show, you will need to provide not only proof of a negative coggins, but also vaccination.
Here is the wording from USEF:
1. At Federation licensed competitions, horses entering the grounds must be accompanied by documentation of Equine Influenza Virus and Equine Herpes Virus (Rhinopneumonitis) vaccinations within six months prior to entering the stables. Horses not in compliance with this rule may be required to leave the competition grounds upon request by Competition Management. Documentation should consist of one of the following methods mentioned below. The frequency of vaccine administration should be per the vaccine manufacturers’ or veterinarian’s recommendations. It is recommended that vaccines are administered by or under the direction of a veterinarian. 2. In the case of vaccines administered by a veterinarian, the exhibitor, upon request by Competition Management, must provide documentation from the veterinarian on documenting that the horse in question received the vaccinations; name of the vaccines and date of vaccine administration. 3. In the case of vaccines administered by a person other than a veterinarian, the exhibitor, upon request by Competition Management, must provide a receipt of the vaccine purchase which is signed by the owner, or agent with care, custody, and control of the horse; name, serial number and expiration date of the vaccine; and date of vaccine administration.