Editor — We refer to the article entitled ‘Equine influenza: a current reference for vets in practice in the UK’ by Rendle et al. in the September/October 2019 issue of UK-Vet Equine (the ‘Article’) (https://doi.org/10.12968/ukve.2019.3.S3.1). We understand that the Article was designed to be a practical and informative piece for veterinary surgeons. As Marketing Authorisation Holder for ProteqFlu® and ProteqFlu-Te® (Boehringer Ingelheim/Merial) we feel obliged and would like to provide further information regarding two segments of the Article as we are concerned that statements included are not consistent with the Summaries of Product Characteristics (SPCs) for Proteq-Flu® and ProteqFlu-Te® and that this could potentially be misleading for veterinary surgeons.
Under the heading ‘Efficacy in foals and interaction with maternally derived immunity’ on page 8 of the Article, the authors discuss that ‘the different vaccines are licensed from different ages’ and provide comment that ProteqFlu® is licensed ‘from 4 months of age’. Whilst it is accurate that ProteqFlu® is licensed for use from 4 months of age, this is only under specific circumstances. According to the Prote-qFlu® SPC ‘in case of increased infection risk or insufficient colostrum intake, an additional injection of ProteqFlu® can be given at the age of 4 months followed by the full vaccination programme (primary vaccination course at 5–6 months of age and 4–6 weeks later followed by revaccination)’. Therefore when following the ProteqFlu® SPC for all other horses it is advised that the first injection in the primary course not be administered until 5–6 months of age; similar to other available equine influenza vaccines in the UK.
Under the heading ‘Vaccine reactions’ on page 9 of the Article, the authors correctly state that ‘the incidence of adverse events reported to the VMD for all currently authorised equine vaccines that vaccinate against equine influenza only and equine flu and tetanus are 0.05% and 0.1% respectively’. The adverse event rates reported on both the ProteqFlu® and ProteqF-lu-Te® SPCs are based on VMD and EMA data and are consistent with the adverse event rates stated in the Article. As such the statement ‘there is a perception among UK practitioners that reactions are more common with the canarypox vector; however this has not been substantiated’ by the authors at the end of the ‘Vaccine reaction’ section has the potential to be misinterpreted by veterinary surgeons. As you may be aware, ProteqFlu® and ProteqFlu-Te® are the only licensed UK equine influenza vaccines to contain a canarypox vector. Therefore our concern is that the Article could give veterinary surgeons the impression that there is a higher adverse event rate with ProteqFlu® and ProteqFlu-Te® based on unsubstantiated evidence. The safety profiles of both ProteqFlu® and ProteqFlu-Te® are reviewed regularly and as such if changes to the adverse event rates occur then the SPCs are updated accordingly.
The above information relating to vaccine reactions has also been summarised in Table 2: ‘Summary of the relative merits of different UK vaccines’ on page 8 of the Article. The table represents the relative merits of the available equine influenza vaccines pictorially by colour code based on the available evidence in the literature and the authors' unpublished data and collective data which we are concerned is unsubstantiated. The footer of Table 2 describes the colour codes within the table as red for poor/absent, amber for moderate, green for good and white for no data which depict the relative merits of the different vaccines.
In Table 2 ProteqFlu® is represented as amber in the column ‘Vaccine reactions’ which means that veterinary surgeons may deem vaccine reactions to be a greater concern with ProteqFlu® compared to other available equine influenza vaccines. As previously stated above, this information relating to vaccine reactions in Table 2 is inconsistent with both the ProteqFlu® and ProteqFlu-Te® SPCs and the VMD/EMA data and in isolation has the potential to be misunderstood and misinterpreted by veterinary surgeons.
We would appreciate for a correction to be published to remedy these inconsistencies.
Kind regards,
Dr Becky Lees