Comparison of the local safety of two multi-component feline vaccines, adjuvanted (1 mL) versus non-adjuvanted at reduced volume (0.5 mL), using computed tomography imaging.

In 2020, a new 0.5 mL presentation of PUREVAX® RCP FeLV was registered and introduced in Europe. The objectives of this study were to investigate the local safety of this non-adjuvanted vaccine at reduced volume by classical methods (clinical examination, histopathology) and to evaluate the suitability of an alternative non-invasive methodology, the computed tomography (CT). For this purpose, the course of local reactions was assessed for 3 months after subcutaneous injection of PUREVAX® RCP FeLV 0.5 mL and compared to an adjuvanted vaccine, LEUCOFELIGEN® FeLV/RCP 1.0 mL. Injection site reactions consisted mainly of swelling reactions, which were more frequent, more pronounced and long-lasting in the adjuvanted vaccine group. Microscopically, in this group, moderate to severe inflammatory reactions were observed on day 7 (D7) and D21 post-injection and still present on D84, while mild inflammatory lesions were observed in the non-adjuvanted vaccine group only on D7 and D21. With the adjuvanted vaccine, inflamed areas were measurable by CT scan in all cats on D7 and D21, whereas they were detected only on D7 and only in 20 % of cats from the non-adjuvanted vaccine group. Besides the higher frequency, the mean inflamed volume was nearly 300 times larger in adjuvanted vaccine group on D7. Using different methodologies, the favorable safety profile of PUREVAX® RCP FeLV 0.5 mL was confirmed. Furthermore, the vaccine is aligned with current vaccination guidelines by inducing less inflammatory reactions, being adjuvant-free and injectable under a reduced volume, thus improving the convenience of administration in recommended sites (eg, legs). CT scan proved to be a suitable non-invasive method for the experimental follow-up of injection site reactions, yielding results consistent with clinical assessment and histopathology on D7 and D21. CT scan substantiated large differences between the investigated vaccines with a more prominent inflammatory reaction after injection of an adjuvanted vaccine.

Informations de copyright

Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.

Déclaration de conflit d'intérêts

Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: VH, FBB, CM, AD, LL, SB and JPT are employees of Boehringer Ingelheim Animal Health. EL and EC are employees of Voxcan, whose contribution to the study was funded by Boehringer Ingelheim Animal Health. AN is employee of VetDiagnostics, whose contribution to the study was funded by Boehringer Ingelheim Animal Health. The contribution of ALG to the publication was funded by Boehringer Ingelheim Animal Health. Verena Haist reports a relationship with Boehringer Ingelheim Animal Health that includes: employment. Fanny Bellebeau-Barbier reports a relationship with Boehringer Ingelheim Animal Health that includes: employment. Camille Montange reports a relationship with Boehringer Ingelheim Animal Health that includes: employment. Aissatou Diawara reports a relationship with Boehringer Ingelheim Animal Health that includes: employment. Laurent Lemaitre reports a relationship with Boehringer Ingelheim Animal Health that includes: employment. Sylvie Brunet reports a relationship with Boehringer Ingelheim Animal Health that includes: employment. Jean-Philippe Tronel reports a relationship with Boehringer Ingelheim Animal Health that includes: employment.