Rocks and hard places – charting a course through the shortage of equine influenza vaccines

You don’t appreciate what you’ve got until it’s gone. The equine influenza vaccination has become so fundamental to equine sport and life in equine practice that we may all be guilty of taking it for granted. Sure, there have been temporary interruptions to the vaccine’s supply in the past, but with three manufacturers producing it, no one anticipated that we would face a situation where we cannot offer the vaccine.

It has long been apparent that there is a need to maintain multiple players in the market to ensure that we have options in the event of a manufacturing glitch or unexpected vaccine failure. But no one planned for a situation where we would be around 65,000 doses of vaccine short and some veterinary practices would go completely out of stock. Our current predicament reinforces concerns around the vulnerability of equine veterinary medical supply chains and our precarious position as a relatively small player in a very large animal health marketplace.

Our current predicament reinforces concerns around the vulnerability of equine veterinary medical supply chains

The current shortage of Proteq and ProteqTE vaccines is reported to have been caused by a software installation failure at one of the major manufacturer’s European hubs. Without the usual IT systems in place, they are unable to process and release the vaccine (and other products), resulting in pan-European shortages of several essential veterinary medicines. Supply issues with Proteq and ProteqTE throughout 2021 had already depleted stocks in wholesalers. No one was very alarmed over the summer rumours that there were still shortages as alternatives had always been available. However, in mid-August, having not put any vaccine into the UK wholesalers since July, the manufacturer’s UK team were informed that they would not be receiving further supplies until the end of October.

BEVA was made aware by the other manufacturers that they could not meet demand, and subsequent calls with the lead supplier confirmed the extent of the problems that lay ahead. Within hours, BEVA was coordinating discussions with the manufacturers and major equestrian sporting bodies to look at how best to manage the unfolding situation. Regular meetings ensued as everyone grappled with not only the threat to equine health but the challenges of maintaining equestrian sport and the long-term impact on owner perception of the importance of the equine influenza vaccination. Estimates of the deficit in vaccines were made from historical sales figures, and models were made of the potential impact of different recommendations on vaccine supply. It quickly became apparent that the vast majority of equine influenza vaccines are administered to leisure, pleasure and lower-level competition horses, and this was where changes would have to be made.

It quickly became apparent that the vast majority of equine influenza vaccines are administered to leisure, pleasure and lower-level competition horses, and this was where changes would have to be made

Communication between different organisations was superb: a positive legacy from the 2019 influenza epidemic when communication between organisations was slow and clunky. In the wake of the 2019 epidemic, the British Equestrian Federation (BEF) established an infectious disease advisory group led by Celia Marr and an emergency response group led by Jenny Hall. This structure, combined with the collegiality of James Given at the British Horseracing Authority (BHA), made it very easy to discuss the matters at hand and to make proposals for managing the challenges ahead. The diversity and autonomy of the large number of organisations within the BEF meant that unilateral recommendations would never be possible, but everyone was at least communicating and working towards a common goal. Communication with the three manufacturers was equally constructive as options for managing supply were discussed.

BEVA has recommended the following measures to preserve vaccine stocks:

• Risk assess each case, considering primarily the horse’s age, past vaccine history and how much it and the others living with it mix
• Vaccinate close to the upper limits for V1-V2 and V2-V3 intervals and subsequent boosters
• Consider deferring annual boosters to 15 months in animals not considered high risk. A risk chart for equine influenza is available on the BEVA website

The proposed extension from 12 to 15 months has been made reluctantly in response to the realisation that if such measures are not taken, younger naïve horses are likely to go without vaccines altogether. While solid scientific data regarding the relaxation of 12-month boosters is lacking, there is limited evidence that horses mount an effective antibody response up to 15 months post-vaccination. The degree of protection conferred at 15 months will not be as good as at 12 months; however, while there is an insufficient vaccine supply, there is a low prevalence of equine influenza in the UK. Furthermore, if enhanced biosecurity is also practised, this temporary measure is unlikely to significantly compromise the health or welfare of the lower-risk animals concerned.

Where a 15-month extended booster interval is adopted in autumn 2022, the subsequent vaccine booster interval should be shortened such that the horse still receives two boosters in a 24-month period from its 2021 booster date. Provided this protocol is followed, mostof the sporting regulatory bodies will not require the course of vaccination to restart. There are further details on different temporary regulations brought in by BEF member bodies online.

It is […] important that we are clear in our messaging that a 15-month vaccination period is suboptimal but tolerable in lower-risk horses at a time when the risk of influenza is low and provided owners are sensible

In the future, the temporary decision to vaccinate at 15-month intervals may be used as ammunition by horse owners who would prefer not to vaccinate at 12-month intervals. It is therefore important that we are clear in our messaging that a 15-month vaccination period is suboptimal but tolerable in lower-risk horses at a time when the risk of influenza is low and provided owners are sensible. It is also crucial that we stress the importance of enhanced biosecurity through this period. The following strategies have, therefore, been proposed:

1. Enhance biosecurity and surveillance, emphasising that owners should be alert to signs of illness in their horses and not to travel or compete them if signs are noted. Rather they should seek veterinary attention as quickly as possible
2. Submit diagnostic samples from horses showing potential signs of flu (fever, cough, nasal discharge)
3. Use the HBLB’s free flu testing scheme
4. Sign up for ICC reports by sending an email request to equine surveillance and for Tell-Tail text alerts here
5. Strongly advocate not introducing unvaccinated horses to equine premises. If this is unavoidable, adopt pre-movement PCR testing, quarantine and five-day post-arrival PCR testing

This biosecurity advice was discussed with the Veterinary Medicines Directorate (VMD) and the Royal College of Veterinary Surgeons (RCVS) on Wednesday 24 and Thursday 25 August 2022.

The VMD has acknowledged that this advice proposes vaccination outside the SPC/datasheet recommendations. As such, they have suggested that we remind members that the decision to vaccinate in line with BEVA advice (out with the marketing authorisation) should be based on the clinical judgement of the prescribing vet, acknowledging that this might take into account that the advice is based on input from experts in equine influenza and vaccine-mediated immunity, and will require a conversation with the horse owner. The VMD has also recognised that during this shortage, it may be impossible for each of the primary vaccination doses (V1, V2 and V3) to be of the same vaccine. It has been shown that mixing vaccines in this way does not compromise antibody responses. Where booster http://www.slaterpharmacy.com/ vaccination does not occur within 12 months, it may be beneficial to annotate the passport flu vaccination record with “Booster delayed due to vaccination shortage”, plus signature, stamp and date (the future value of this entry is under discussion with the BEF).

Given the nature of vaccine supply contracts, measures to preserve vaccine stocks will have a limited impact if practices are not prepared to assist those who do not have access to equine influenza vaccine

Given the nature of vaccine supply contracts, measures to preserve vaccine stocks will have a limited impact if practices are not prepared to assist those who do not have access to equine influenza vaccine. The VMD has made it clear that as the current situation presents a threat to equine health and welfare, vaccines may be sold between practices. It is testament to the corporate groups’ recognition of their important role in the UK horse sector that representatives from CVS, IVC Evidensia and VetPartners met at BEVA Congress. Here they volunteered to encourage their practices, where stock is available, to assist those local or referring practices that do not have sufficient vaccines, to ensure that high-risk patients have access to vaccinations.

An application has been made to import a significant quantity of combined equine influenza and herpes vaccine from the USA, but as I write we are still waiting for a decision from the regulator on whether the import of this product will be permitted. Even in such challenging circumstances, the regulatory cogs turn slowly…