The vaccine was pulled from use a few yeas ago when the efficacy dropped below what the company considered adequate. There was no safety issue with the vaccine. The relaunched vaccine has the same protocol i.e 2 vaccines 4 weeks apart and then booster vaccines every 3 to 6months depending on the degree of risk to the individual horse. Foals can be done from 4 months. The vaccine is a low volume dose given inside the upper lip. Occasional local reactions are seen.
Isolated individuals or horses in small groups with little or no chance of meeting animals of unknown history are unlikely to need vaccinating. However owners of horses in larger yards or those frequently travelling and staying away should consider vaccination.
As a practice we would recommend that any yard owner should implement a 21 day isolation policy with a blood sample towards the end of the quarantine period as a minimum precaution against introducing a carrier.