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Virus‐neutralising antibody responses in horses following vaccination with Equivac® HeV: a field study
Author(s) -
Tan RHH,
Hodge A,
Klein R,
Edwards N,
Huang JA,
Middleton D,
Watts SP
Publication year - 2018
Publication title -
australian veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.382
H-Index - 59
eISSN - 1751-0813
pISSN - 0005-0423
DOI - 10.1111/avj.12694
Subject(s) - vaccination , medicine , antibody , hendra virus , immunity , virus , virology , antibody titer , booster dose , titer , neutralizing antibody , immunology , immune system , encephalitis
Objective To determine the antibody responses to a commercial Hendra virus vaccine (Equivac® HeV) in a field environment. Methods A group of 61 horses received a primary vaccination course comprising two doses administered 3–6 weeks apart (V1, V2) and a 3rd dose (V3) given 6 months after the second. This was followed by booster vaccinations at 12 monthly intervals (V4, V5). Antibody titres were assessed using a virus‐neutralisation test. Results Neutralising antibodies against HeV were not detected prior to vaccination. Antibodies were detected in 54/57 horses at 3 weeks after V1 and 51/51 had titres ≥ 32 at 8 weeks after V2. At 6 months after V2, antibody titres decreased in most (31/34) horses and were not detected in three horses. A rapid increase in antibody titres was recorded in 35/36 horses at 1 week following V3. By the first annual booster vaccination (V4), antibodies were still detectable in 29/29 horses, although titres had decreased; in 26/29 horses, titres remained ≥ 32. All horses showed an increase in antibody titres after V4. There was no statistically significant increase in mean antibody titre after V5, compared with after V4. Conclusion Horses administered Equivac® HeV, using a primary vaccination course followed by annual booster vaccinations, mounted an effective secondary immune response and acquired antibody responses that were consistent with protective immunity against HeV in the form of virus‐neutralising antibodies. No adverse events were observed after vaccine administration.