Effect of dexamethasone on antibody response of horses to vaccination with a combined equine influenza virus and equine herpesvirus-1 vaccine.
Authors: Kreutzfeldt Nicole, Chambers Thomas M, Reedy Stephanie, Spann Kennedy Michelle, Pusterla Nicola
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary Corticosteroid administration is commonplace in equine practice, yet little evidence exists regarding its impact on vaccine efficacy—a gap this 2024 research addresses directly. Researchers vaccinated 55 healthy horses against equine influenza virus (EIV) and equine herpesvirus-1 (EHV-1) whilst administering either no dexamethasone, a single IV dose (~0.05 mg/kg), or three doses at 24-hour intervals, measuring antibody responses via haemagglutination inhibition and multiplex ELISA at day 30 post-vaccination. Only vaccinated horses receiving no corticosteroid showed a statistically significant increase in EIV-specific antibodies (mean titre increase from 166.9 to 249.1, P = 0.02), whilst a single dexamethasone dose preserved this response (93.14 to 185.1, P = 0.01)—but multiple doses suppressed it entirely (194.3 to 240.0, P > 0.05); notably, neither treatment regimen generated meaningful EHV-1 antibody responses. For practitioners, these findings suggest that a single corticosteroid administration concurrent with vaccination may be tolerated, yet repeated dosing within 72 hours warrants reconsidering vaccination timing, and the notably poor EHV-1 response across all groups raises questions about this particular vaccine's efficacy in these conditions.
Read the full abstract on PubMed
Practical Takeaways
- •If dexamethasone therapy is necessary around vaccination, a single dose appears less likely to compromise EIV antibody response than multiple doses
- •Multiple doses of dexamethasone given at 24-hour intervals may impair the development of protective EIV antibodies and should ideally be avoided perivacinally
- •EHV-1 vaccine response was poor across all groups in this study; practitioners should consider revaccination protocols or alternative vaccine schedules
Key Findings
- •Vaccination alone produced significantly increased mean EIV antibody titers (166.9 to 249.1, P=0.02)
- •Single-dose dexamethasone did not suppress EIV antibody response (93.14 to 185.1, P=0.01)
- •Multiple doses of dexamethasone (3 doses at 24-hour intervals) prevented significant EIV antibody titer increase (194.3 to 240.0, P>0.05)
- •No significant antibody increases against EHV-1 were detected in any treatment group