Selvom det ikke er vist med denne særlige AI vaccine- stamme, har studier med andre stammer vist, at beskyttende niveauer af serum- antistoftitre hos kyllinger forventes at vare ved i mindst 12 måneder efter indgivelse af to vaccinationer.
Although it has not been investigated with this particular AI vaccine strain, studies performed with other strains show that protective levels of serum antibody titres would be expected to persist in chickens for at least 12 months after administration of two doses of vaccine.