Everyone will no doubt be aware of the increasing number of ‘flu outbreaks in the UK this year and, more concerningly, reports from Newmarket involving infection in vaccinated horses. Given recent history it is assumed that the recent outbreaks involve Florida clade 1 virus.
In view of the evidence of infection in vaccinated horses, it is crucial that an accurate message is given to horse owners to avoid loss of confidence in vaccination which will make the situation even worse. In this respect it is important to realise that it is not simply a case of vaccine failure, and we should point out that:
1) vaccinated horses tend to be more susceptible towards the end of the vaccine interval (that is when the next booster is due), and,
2) vaccinated horses tend to have less severe clinical signs, if any all.
We should advise that any horse that has not received a vaccine containing a Florida Clade 1 strain within the last 3-6 months receives a booster ASAP. This is likely to offer good clinical protection.