It was done in chickens, and some scientists say it has little relevance for human vaccination; they worry it will reinforce doubts about the merits or safety of vaccines. (sciencemag.org)
Like with human vaccinations, the H3N2 vaccine is not 100 % guaranteed to prevent infection but it drastically reduces the likelihood, and usually reduces the severity if infection does occur. (parkavenuevets.com)
Pet vaccinations function much the same as human vaccinations. (companionsk.com)