The widespread outbreak of the COVID-19 pandemic is the most severe global public health event since the Second World War, posing an immense threat to human health. Countries globally imposed measures such as lockdown, social distancing etc. Since Dec 7 2022, there has been a gradual relaxation of the dynamic zero-COVID policy in China, which indicated a new stage of China’s pandemic prevention and control. Due to the gradual relaxation of the dynamic zero-COVID policy after December 2022, the number of COVID-19 infections in China has surged. As the COVID-19 virus continued to mutate, the public faces the threat of single or multiple infections. The COVID-19 pandemic has brought almost indiscriminate health impacts to the entire Chinese population.
Health impacts usually refer to welfare losses caused by serious threats to family members' health within a specific time period (Bairoliya et al., 2018; Da Costa, 2020; Nam et al., 2010). Among various risk impacts, health impacts are central and key factors leading to household poverty, with short-term impacts on households far outweighing long-term ones, making them susceptible to temporary (Araujo & Coelho, 2021; L. J. Qin et al., 2021; Sweeney et al., 2021). The latest global evidence shows that at least 1.4 billion people faced catastrophic health expenditure, leading to poverty in 2017 (WHO, 2021). A study on the Philippines indicated that negative external impacts lead to a decrease in individual quality of life and a deepening of poverty (Datt & Hoogeveen, 2003). Enormous medical expenses resulting from health impacts impose a heavy economic burden on families, severely limiting their wealth and leading them to prioritize current consumption. In the short term, it directly leads to the loss of patients' labor capacity and the loss or deprivation of time for family members to participate in production activities due to care responsibilities, thereby negatively affecting household or individual labor income (K. Alam & Mahal, 2014; Grafova et al., 2020; Y. J. Wang et al., 2023).
The medical insurance system, through a risk-sharing mechanism, establishes a safety net for insured individuals to prevent impoverishment due to illness. Once medical expenses occur, insurance covers the majority, and individuals only bear a small portion, thereby alleviating the economic burden on patients (Ma et al., 2022; Mercado, Chesky et al., 2023; Yun et al., 2022). Since the 1990s, China has gradually established three primary medical insurance systems: the Urban Employee Medical Insurance Scheme (UEMI), the Urban Resident Basic Medical Insurance Scheme (URBMI), and the New Rural Cooperative Medical Scheme (NRCMS)1. Research has found that UEMI, URBMI and NRCMS effectively reduce individual vulnerability (Dou et al., 2018). However, the division between urban and rural areas in medical insurance has resulted in significant disparities for residents in terms of medical treatment, coverage for medication reimbursements, and the number of designated hospitals available. China's fragmented medical insurance system has the problem of unequal treatment. In 2016, the Chinese government merged the URBMI and the NRCMS into the Urban and Rural Resident Basic Medical Insurance (URRMI), unifying the medical insurance coverage for rural residents and urban informal workers, marking a new phase in China's medical insurance system.
Currently, China's medical insurance system comprises the UEMI for formal urban employees and the URRMI for informally employed urban and rural residents. The UEMI which safeguards formal employment provides significantly better coverage than the URRMI which safeguards non-formal employment for urban and rural residents. Further to this, it has been proven that different medical insurance systems do indeed have an impact on health inequities (Diao & Liu, 2020; Palacios et al., 2020; Z. W. Wang et al., 2019; X. Zhang et al., 2015). Since the outbreak of the COVID-19 pandemic, there have been numerous studies on COVID-19 and its impacts on the economy and society globally (M. J. Alam et al., 2023; Holmes et al., 2020; Nicola et al., 2020; Ramaiya et al., 2023; Z. K. Zhang & Neupane, 2024). The COVID-19 pandemic has exhibited significant features such as a wide transmission range and prolonged duration, causing lasting harm to people's physical and mental health. It may exacerbate disparities in health levels among different social groups, especially between groups covered by different medical insurance systems. Due to China's strict epidemic prevention and control policies and limited spread for a long time, however, there had not been much investigation of the relationship between different medical insurance systems and health equity in the context of the COVID-19 until December 2022. Although China has integrated the NCMC and the UEMI into the URRMI, there still exist separate UEMI with regular employment and for urban and rural residents with non-regular employment. The medical insurance reimbursement benefits for working urban residents are much higher than those for urban and rural residents. Therefore, studying the impact of COVID-19 and investigating the health equity effects of different medical insurance systems under the influence of COVID-19 are of great practical significance.