Equine Influenza Outbreak

Equine Influenza Outbreak 

Just to clarify, there have been seven outbreaks of Equine Influenza in 2019, the most recent at the start of February.  These have been in Essex, Cheshire, Derbyshire, Lincolnshire, Yorkshire, Leicestershire and two in Suffolk.  With the exception of one of the Suffolk outbreaks on 4th February, these have been in unvaccinated horses.  The outbreak in vaccinated horses has involved 8 two-year old horses that had different vaccines.  Today, two further cases in Cheshire and Leicestershire have also been reported.  

Previous to these, recent outbreaks in France in 2018, vaccinations using Proteq (the vaccine we use) have protected the horses by preventing the cough, stopping high temperatures and reducing viral shedding by stopping snotty noses.  

Proteq is the only vaccine that contains the Florida Clade One (FC1) and Florida Clade Two (FC2). The World Organisation for Animal Health (OIE) recommend the use of these two Clades in all Equine Influenza vaccines to protect horses.  Therefore, I believe that our vaccine, Proteq Flu and Proteq Flu & Tetanus, is the most up-to-date and most likely to prevent or reduce the severity of Equine Influenza. 

Young horses (less than 4 years old), older horses (c20+) and those with Cushing’s or others with weakened immune systems should be regarded as the most at risk because they are the most likely to contract Equine Influenza.  

Using the vaccine “properly” by following the manufacturer’s recommendations of 

  • Two vaccinations 4-6 weeks apart 
  • A third vaccine at 5-6 months following the second vaccination 

…..is the best way to protect your horse under normal circumstances.  However, it is interesting that the FEI requires a vaccination within the last 6 months for competitions suggesting that the immunity may wane or weaken beyond 6 months.  This is beyond the manufacturer’s recommendations but having spoke to them, they are happy to follow the vet’s clinical judgement, if they think that 6 monthly boosters are indicated.  

A study in 2011 suggested that some horses had antibody levels that had dropped by 6 months post-vaccination and mooted that vaccinating younger horses, particularly should be done more frequently!! 

To convert from one vaccine to another can be done although it is better to give an extra vaccine to maximise the immunity. 




Gildea S, Arkins S, Walsh C, Cullinane A. (2011) A comparison of antibody responses to commercial equine influenza vaccines following annual booster vaccination of National Hunt horses - a randomised blind study. Vaccine. 29, (22), 3917-22