Avian influenza H5N1 remains a major global concern due to its expanding host range and potential for human adaptation. Using an agent-based model parameterized with the demographics and contact patterns of a high-risk poultry-farming region in Canada, we evaluated how self-isolation of symptomatic cases and targeted vaccination of poultry farmers and their households affect transmission dynamics following a spillover event. Simulations were initiated with a subcritically transmissible virus (R0?=?0.2) that allowed for mutations capable of increasing transmissibility within infected hosts. We found that even when transmissibility remained below unity, extended multi-generation human-to-human transmission chains can occur, providing opportunities for adaptive mutations. High compliance with self-isolation markedly reduced the likelihood of these chains, and pre-emptive vaccination before spillover further reduced cumulative infections. Strengthening surveillance and detection systems, alongside prompt behavioural measures and targeted immunization, could prevent the virus from attaining epidemic-level transmissibility and enable containment of spillover events.