Health inequality creates conditions for the transmission of infectious diseases, and existing health disparities can contribute to unequal burdens of morbidity and mortality. In Hong Kong, low socioeconomic districts were the epicentres of third-wave outbreak of COVID-19 in July and August 2020, suggesting that people from low socioeconomic class are vulnerable groups. Socially disadvantaged people are relatively more vulnerable to the physical, mental, and social impacts of infectious diseases. To achieve more effective infection control, the social determinants of health and existing health inequalities should be identified, and understanding the experiences of socially disadvantaged groups in the COVID-19 outbreak will be beneficial to health authorities in formulating a responsive infection control policy targeting the needs of the socially disadvantaged. This article investigates the experiences of economically disadvantaged groups during the COVID-19 outbreak and examines how they were further disadvantaged in the outbreak by delineating how health inequality intersected with social inequality. In-depth, semistructured interviews were conducted from February to April 2020 with 35 participants from the poverty class in Hong Kong. The high prices of surgical face masks and disinfecting products as well as the economic impacts induced by COVID-19-related social distancing policies imposed severe economic burden on the participants. In addition to economic and housing deprivation, social inequality was closely associated with health inequality, which made the participants more vulnerable to infection. Social inequality is associated with and can worsen health inequality. Here, the participants, who were of low socioeconomic status were more disadvantaged in health and in the attainment of social resources such as employment, education, face masks, disinfection products and right to use public facilities, during the COVID-19 outbreak. All these elements may have interrelated effects and in turn limit accessibility to healthcare and lead to less positive health outcomes and consequently to health inequality.