Advances and Challenges of Epidemic Outbreaks in the Post-COVID-19 Era in China

The coronavirus disease 2019 (COVID-19) outbreak, caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2),^[1] has spread globally, having profound impacts on peoples' lives, social and economic activities, and national security. Throughout the pandemic, China has adopted a policy of putting “the people and their lives first” and provided comprehensive free medical care for all infected patients.^[2] The first wave of Wuhan outbreak was successfully controlled within 3 months in early 2020. Since then, China has effectively curbed more than 100 clusters of SARS-CoV-2 infections and subsequent outbreaks, and 5 waves of global epidemics from 2020 to 2021. Overall, the proportion of confirmed cases in China is 0.27% of the global average, and the case fatal rate is 0.43% of the global average.^[3] These achievements emphasize the important role that professional medical care and holistic nonpharmaceutical intervention played from 2020 to the end of 2021, in protecting the population from SARS-CoV-2 infection and death associated with COVID-19 in China [Figure 1].

Figure 1: Advances and challenges against COVID-19 in China. (A) Weekly confirmed cases and deaths from COVID-19 from January 2020 to December 2022, in mainland China. Data from the National Health Commission of China. Milestones in virology (yellow), policy (blue), vaccine development (green), and drug development (purple). (B) A list of challenges in the post-COVID-19 era on virology, policy, vaccine, and drug development.

The past 3 years keeping COVID-19 at bay in China have been hard. Despite this, professionals have continuously explored more effective ways to contain the spread of the virus and actively optimize epidemic control measures while striking a balance between protecting public health and ensuring social and economic development.

The Omicron variant emerged in November 2021, quickly becoming the dominant strain and spreading globally. After the winter of 2022, the Omicron variants BA.5.2 and BF.7 have led to multiple outbreaks in major provinces and cities in China. Recently, government authorities have optimized the policy on epidemic prevention and control by issuing 20 measures and 10 new measures on November 11 and December 7, respectively. In addition, the management of COVID-19 has been downgraded from class A to class B since the January 8, 2023. These improvements in COVID policy are based on a comprehensive evaluation of virus characteristics, epidemic situations, vaccination coverage, medical resources, and experiences.

First, the current Omicron variant spreads quickly with cases of new infection, reinfection, and breakthrough infection, outpacing other variants of concern (VOCs). Omicron cannot be stopped but is less virulent than earlier strains such as Alpha and Delta. During the Omicron BA.2 sublineage outbreak in Shanghai from February to June 2022, the overall fatality ratio and risk of developing severe or critical disease upon infection were 0.09% and 0.27%, respectively.^[3] This is much lower than those of the other earlier strains. Second, the current prevalent Omicron strains mainly infect the upper respiratory tract and rarely cause pneumonia. Moreover, more than 99% of cases are mild to moderate, with flu-like and upper respiratory symptoms. Most hospitalized patients test negative for approximately 4 to 7 days. As such, China has updated its holistic medical care, nonpharmaceutical intervention measures, diagnosis, and treatment protocol for COVID-19 patients.^[4] For example, antiviral agents including Paxlovid and Azvudine have been used in clinical practice. Moreover, several phase II/III clinical trials, such as those for meplazumab^[5] and VV116,^[6] have been conducted to treat severe COVID-19. Notably, there have been significant improvements in public health management. By the end of 2022, there were more than 16,000 fever clinics in secondary and tertiary hospitals and more than 41,000 fever clinics in community-level health institutions. The total number of intensive care unit beds was 181,000, equating to 12.8 beds per 100,000 individuals.^[7] Moreover, the combined expertise and skill of experts and medical staff have been used to coordinate a better response to the current epidemic. Government authorities have approved 13 vaccine candidates for emergency use, including 5 inactivated vaccines, 5 recombinant protein vaccines, and 3 vector-based vaccines. More than 90% of the Chinese population have been vaccinated once or received a third booster dose. Furthermore, the second booster shot was approved for high-risk populations including the elderly, people with coexisting diseases, and people who are immunocompromised.^[8] The valuable experience from other country, such as Singapore, which has already adopted a COVID-19 opening-up policy, serves as an important reference for mainland China.

Within the first few weeks of policy changes, the first wave of peak infections occurred in cities and rural areas. Currently, we are facing challenges. First, surging COVID-19 infections may lead to shortages of health care supplies including diagnostic agents, antiviral drugs, antipyretics, therapeutic drugs, inpatient beds, and devices. The number of patients attending fever clinics has surged, with the number of patients treated in intensive care unit tripling from previous levels. Second, COVID-19 inpatients have shifted from patients with mild/moderate symptoms to more severe/critical patients including elderly people and people with multiple comorbidities, such as hypertension, diabetes, and chronic lung diseases. Furthermore, infection of medical workers will inevitably lead to a decrease in available medical staff. Third, new Omicron subvariants, such as BQ.1 and XBB, are prevalent in some countries evading immune barriers established by previous vaccinations and natural infections. New variants of the virus, either newly emerging or imported, pose potential risks of reinfection and further epidemic waves. Fourth, misinformation-spreading presents a significant challenge to public health.

To better deal with the challenges mentioned previously, government authorities and medical institutions have made great efforts to maximize capacity to meet medical demands and minimize severe illness and death. First, a hierarchical health management system has been created based on different risk groups, with a focus on early intervention and treatment to prevent severe illness. Asymptomatic and mild cases should self-quarantine at home under the instruction of local medical clinics or communities. Moderate, severe, and critical cases of COVID-19, particularly elderly patients with comorbidities, are advised to seek medical attention as soon as possible. Second, hospital fever clinics have been strengthened by ensuring sufficient medical staff, drug supplies, and necessary equipment. Free health care packages are being distributed to residents in many places. Moreover, makeshift hospitals, gyms, and nucleic acid sampling sites have been converted into temporary fever, diagnosis, and treatment sites to meet the demands of patients. However, through mass, social, and we-media, health care professionals should take concerted action against misinformation to promote and distribute accurate health information to the public. In addition, more efforts are needed to optimize the allocation of medical resources, accelerate the construction of fever clinics, and train professionals in infectious diseases and critical respiratory illnesses. Moreover, sufficient care and support should be provided to frontline medical staff. In addition, further promotion of vaccination among the elderly, most vulnerable populations, and those living in rural areas is necessary. Furthermore, sentinel monitoring of VOCs in key areas, such as medical institutions, schools, and nursing homes, should be continued. Ultimately, the aim is to seek a balance between disease control and socioeconomic development in China and help to downgrade the COVID-19 epidemic from a global health emergency.

After 3 years of the COVID-19 epidemic, it is hoped that the COVID-19 pandemic is close to an end. However, to successfully end the COVID-19 pandemic, as well as adapting and optimizing COVID-19 management, close international cooperation in scientific research and innovation is needed for several critical issues. These include the following: close monitoring of potential new VOCs, improving the understanding of protective immunity against infection and disease deterioration, improving understanding of the immunopathogenesis of COVID-19, and the development of highly efficient antiviral drugs, therapeutics, and prophylactic vaccines. Integrative efforts between China and other nations will ensure a smoother and faster end to the COVID-19 epidemic globally.