Toll-Like Receptor Signaling in Severe Acute Respiratory Syndrome Coronavirus 2-Induced Innate Immune Responses and the Potential Application Value of Toll-Like Receptor Immunomodulators in Patients With Coronavirus Disease 2019.

Toll-like receptors (TLRs) are key sensors that recognize the pathogen-associated molecular patterns (PAMPs) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to activate innate immune response to clear the invading virus. However, dysregulated immune responses may elicit the overproduction of proinflammatory cytokines and chemokines, resulting in the enhancement of immune-mediated pathology. Therefore, a proper understanding of the interaction between SARS-CoV-2 and TLR-induced immune responses is very important for the development of effective preventive and therapeutic strategies. In this review, we discuss the recognition of SARS-CoV-2 components by TLRs and the downstream signaling pathways that are activated, as well as the dual role of TLRs in regulating antiviral effects and excessive inflammatory responses in patients with coronavirus disease 2019 (COVID-19). In addition, this article describes recent progress in the development of TLR immunomodulators including the agonists and antagonists, as vaccine adjuvants or agents used to treat hyperinflammatory responses during SARS-CoV-2 infection.

Early diagnosis and population prevention of coronavirus disease 2019.

PURPOSE OF REVIEW: To discuss the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by nucleic acid and antibody testing as well as its contribution to mitigating the spread of coronavirus disease 2019. RECENT FINDINGS: Nucleic acid testing (NAT) is the firstly developed and most widely used diagnostic technique for SARS-CoV-2 infection. However, the sensitivity of SARS-CoV-2 RNA NAT assays is always unsatisfactory, mainly due to insufficient viral RNA in samples, especially when upper respiratory samples were used. Compared with NAT assays, serological tests are more convenient and less dependent on the quality of sample collection. But the sensitivity of antibody assays varies largely to test samples collected at different time after onset of symptoms. The diagnostic sensitivity can be significantly improved by combination of RNA and antibody testing. Due to the lack of effective drugs and vaccines, population prevention results mainly from timely triage and quarantine of SARS-CoV-2 infected individuals. Thus, extensive testing with NAT and antibody assays simultaneously is very important to constrain coronavirus disease 2019 epidemic. SUMMARY: Viral RNA testing combining with serological testing could improve the early diagnosis of SARS-CoV-2 infection, which has great value for clinical practice and public health.

Public Voice via Social Media: Role in Cooperative Governance during Public Health Emergency.

With the development of the Internet, social networking sites have empowered the public to directly express their views about social issues and hence contribute to social change. As a new type of voice behavior, public voice on social media has aroused wide concern among scholars. However, why public voice is expressed and how it influences social development and betterment in times of public health emergencies remains unstudied. A key point is whether governments can take effective countermeasures when faced with public health emergencies. In such situation, public voice is of great significance in the formulation and implementation of coping policies. This qualitive study uses China's Health Code policy under COVID-19 to explore why the public performs voice behavior on social media and how this influences policy evolution and product innovation through cooperative governance. A stimulus-cognition-emotion-behavior model is established to explain public voice, indicating that it is influenced by cognitive processes and public emotions under policy stimulus. What is more, as a form of public participation in cooperative governance, public voice plays a significant role in promoting policy evolution and product innovation, and represents a useful form of cooperation with governments and enterprises to jointly maintain social stability under public health emergencies.

A five-compartment model of age-specific transmissibility of SARS-CoV-2.

BACKGROUND: The novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, also called 2019-nCoV) causes different morbidity risks to individuals in different age groups. This study attempts to quantify the age-specific transmissibility using a mathematical model. METHODS: An epidemiological model with five compartments (susceptible-exposed-symptomatic-asymptomatic-recovered/removed [SEIAR]) was developed based on observed transmission features. Coronavirus disease 2019 (COVID-19) cases were divided into four age groups: group 1, those ≤ 14 years old; group 2, those 15 to 44 years old; group 3, those 45 to 64 years old; and group 4, those ≥ 65 years old. The model was initially based on cases (including imported cases and secondary cases) collected in Hunan Province from January 5 to February 19, 2020. Another dataset, from Jilin Province, was used to test the model. RESULTS: The age-specific SEIAR model fitted the data well in each age group (P < 0.001). In Hunan Province, the highest transmissibility was from age group 4 to 3 (median: ß43 = 7.71 × 10- 9; SAR43 = 3.86 × 10- 8), followed by group 3 to 4 (median: ß34 = 3.07 × 10- 9; SAR34 = 1.53 × 10- 8), group 2 to 2 (median: ß22 = 1.24 × 10- 9; SAR22 = 6.21 × 10- 9), and group 3 to 1 (median: ß31 = 4.10 × 10- 10; SAR31 = 2.08 × 10- 9). The lowest transmissibility was from age group 3 to 3 (median: ß33 = 1.64 × 10- 19; SAR33 = 8.19 × 10- 19), followed by group 4 to 4 (median: ß44 = 3.66 × 10- 17; SAR44 = 1.83 × 10- 16), group 3 to 2 (median: ß32 = 1.21 × 10- 16; SAR32 = 6.06 × 10- 16), and group 1 to 4 (median: ß14 = 7.20 × 10- 14; SAR14 = 3.60 × 10- 13). In Jilin Province, the highest transmissibility occurred from age group 4 to 4 (median: ß43 = 4.27 × 10- 8; SAR43 = 2.13 × 10- 7), followed by group 3 to 4 (median: ß34 = 1.81 × 10- 8; SAR34 = 9.03 × 10- 8). CONCLUSIONS: SARS-CoV-2 exhibits high transmissibility between middle-aged (45 to 64 years old) and elderly (≥ 65 years old) people. Children (≤ 14 years old) have very low susceptibility to COVID-19. This study will improve our understanding of the transmission feature of SARS-CoV-2 in different age groups and suggest the most prevention measures should be applied to middle-aged and elderly people.

A comparative study of the laboratory features of COVID-19 and other viral pneumonias in the recovery stage.

BACKGROUND: Clinical recovery does not mean full recovery. It is necessary to explore the aftereffects of COVID-19 in patients and compare the laboratory features of COVID-19 and other viral pneumonias in the recovery stages. METHODS: Forty-seven cases of COVID-19 and 45 cases of other viral pneumonias (control) were included in this study. The laboratory parameters were compared between COVID-19 and control patients as well as severe and moderate COVID-19 patients from the clinical recovery stage to the 4 weeks postdischarge recovery stage. RESULTS: A higher RDW-CV level and neutrophil percentage and lower levels of total proteins, lymphocytes, eosinophils, and MCH were found in COVID-19 patients compared with those in controls from the clinical recovery to the postdischarge recovery stages. Further analysis showed that decreases in lymphocytes, total proteins, and SOD and elevations in neutrophils, FDP, CRP, and ESR were more common in severe than moderate cases of COVID-19 during hospitalization; however, differences in these indicators, except total proteins, were not observed in the postdischarge recovery stages. Additionally, only 76.9% of COVID-19 patients were positive for IgG antibodies against SARS-CoV-2 in the convalescence stage, and one patient that was negative for specific IgG was reinfected. CONCLUSIONS: This study demonstrated that patients recovering from COVID-19 might need better care than that patients with other viral pneumonias due to the possibility of having poor immunity and nutritional conditions. These findings provide new insights to improve the understanding of COVID-19 and improve care for patients affected by these kinds of pandemics in the future.

Expert consensus on prevention and control of COVID-19 in the neurological intensive care unit (first edition).

During the COVID-19 epidemic, the treatment of critically ill patients has been increasingly difficult and challenging. During the epidemic, some patients with neurological diseases also have COVID-19, which could be misdiagnosed and cause silent transmission and nosocomial infection. Such risk is high in a neurological intensive care unit (NCU). Therefore, prevention and control of epidemic in critically ill patients is of utmost importance. The principle of NCU care should include comprehensive screening and risk assessment, weighing risk against benefits and reducing the risk of COVID-19 transmission while treating patients as promptly as possible.