The efficacy of inactivated oil-emulsion H9N2 avian influenza vaccine

Document Type: Short paper

Authors

1 Department of Poultry Research and Production Vaccines, Razi Vaccine and Serum Research Institute, Karadj, Iran

2 Department of Poultry Diagnostic and Research, Razi Vaccine and Serum Research Institute, Karadj, Iran

3 Department of Microbiology, Razi Vaccine and Serum Research Institute, Karadj, Iran

Abstract

An experimental inactivated oil-emulsion H9N2 avian influenza vaccine was formulated with 3 parts of
inactivated avian influenza antigen A/Chicken/Iran/101/1998(H9N2) emulsified in 7 parts of oil adjuvant.
Twelve week-old specific pathogen-free (SPF) chickens were divided into seven groups of 10 birds. Six
groups were vaccinated with 1, 1/10th, 1/50th, 1/100th, 1/200th and 1/400th field dose of the experimental
avian influenza vaccine (EAIV). The last group, was injected with saline and served as the control group.
The mean titer in haemagglutination inhibition (HI) test (log 2) on the vaccinated groups, 21 days postvaccination were 6.0, 4.4, 3.83, 3.3, 3.0 and 2, respectively. Prevention of virus shedding through cloaca was used as the potency test which revealed that the protective doses 50% (PD50) of full, 1/10th and 1/50th of the field dose of the experimental vaccine were 100, 100 and 96.25%, respectively. Those groups that
received <1/50th dose could not prevent virus shedding. So it can be concluded that EAI vaccine could even
be entirely protective and efficient in 1/10th dose and got a desirable immunity in experimental SPF
chickens.

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