The key epidemiological difference between pandemic and seasonal influenza is that the population is largely susceptible during a pandemic, whereas, during non-pandemic seasons a level of immunity exists. The population-level efficacy of household-based mitigation strategies depends on the proportion of infections that occur within households. In general, mitigation measures such as isolation and quarantine are more effective at the population level if the proportion of household transmission is low.
Kwok, K. O., Leung, G. M., & Riley, S. (2011). Modelling the proportion of influenza infections within households during pandemic and non-pandemic years. PLoS ONE, 6(7). https://doi.org/10.1371/journal.pone.0022089