Hong Kong, as mainland China, Taiwan and New Zealand has been adopting zero COVID-19 policy in the past few years; hence, population immunity from natural infections was low. How booster doses along with interventions and seasonal factors can effectively control the outbreak by Omicron in these countries remains unknown. Hong Kong, has been struggled in managing the fifth wave caused by Omicron initially, leading to an excess number of deaths. But the outbreak begins decline few weeks after social distancing tightening and rapid antigen test (RAT) kits were used. We extended a model with stratified immunity to incorporate empirical results of antibody responses from people taking Coronavac or BioNTech and effects of other interventions. The model quantified the impacts of social distancing regulations, RAT, vaccine booster and seasonal factors on the cumulative incidence.