Epidemiological characteristics of seasonal influenza under implementation of zero-COVID-19 strategy in China.

OBJECTIVE: Respiratory viral diseases have posed a persistent threat to public health due to their high transmissibility. Influenza virus and SARS-Cov-2 are both respiratory viruses that have caused global pandemics. A zero-COVID-19 strategy is a public health policy imposed to stop community transmission of COVID-19 as soon as it is detected. In this study, we aim to examine the epidemiological characteristics of seasonal influenza in the past five years before and after the emergence of COVID-19 in China and observe the possible impact of the strategy on influenza. METHODS: Data from two data sources were retrospectively analyzed. A comparison on influenza incidence rate between Hubei and Zhejiang provinces was conducted based on data from the Chinese Center for Disease Control and Prevention (CDC). Then a descriptive and comparative analysis on seasonal influenza based on data from Zhongnan Hospital of Wuhan University and Hangzhou Ninth People`s Hospital before and after the outbreak of SARS-CoV-2 was conducted. RESULTS: From 2010-2017, both provinces experienced relatively low influenza activity until the 1st week of 2018, when they reached peak incidence rates of 78.16/100000PY, 34.05/100000PY respectively. Since then, influenza showed an obvious seasonality in Hubei and Zhejiang until the onset of COVID-19. During 2020 and 2021, there was a dramatic decline in influenza activity compared to 2018 and 2019. However, influenza activity seemed to rebound at the beginning of 2022 and surged in summer, with positive rates of 20.52% and 31.53% in Zhongnan Hospital of Wuhan University and Hangzhou Ninth People`s Hospital respectively as of the time writing this article. CONCLUSIONS: Our results reinforce the hypothesis that zero-COVID-19 strategy may impact the epidemiological pattern of influenza. Under the complex pandemic situation, implementation of NPIs could be a beneficial strategy containing not only COVID-19 but also influenza.

Prevalence and coagulation correlation of anticardiolipin antibodies in patients with COVID-19.

We aimed to determine prevalence and characteristics of anticardiolipin antibodies (ACLs) and its correlations with laboratory coagulation variables in patients with coronavirus disease 2019 (COVID-19). We retrospectively analyzed the prevalence of serum ACLs and its correlation with coagulative laboratory variables in 87 patients with COVID-19. ACLs were detected in 13/21 (61.91%) critically ill patients, and 21/66 (31.82%) in non-critically ill patients. For ACLs, IgA, and IgG were the most common types. The prevalence of IgG in critical ill patients was much higher than that in non-critical patients with odd ratio = 2.721. And the levels of all isotypes of ACLs in critically ill patients were much higher than those in non-critically ill patients. Correlation analysis showed that activated partial thromboplastin time and thrombin time had weak correlation with ACLs-IgG (R = 0.308, P = .031; R = 0.337, P = .018, respectively). Only the prevalence of ACLs-IgG shows a significant difference when compared critically ill patients with non-critically ill patients. ACLs do not seem to have a clear correlation with thrombosis occurred in COVID-19 patients.

The incidence of influenza in children was decreased in the first flu season after COVID-19 pandemic in Wuhan.

Wuhan, China was the first city to discover COVID-19. With the government's macro-control and the active cooperation of the public, the spread of COVID-19 has been effectively controlled. In order to understand the additional impact of these measures on the prevalence of common influenza, we have collected flu test data from the Pediatric Clinic of Zhongnan Hospital of Wuhan University from September to December 2020, and compared them with the same period in 2018 and 2019. It is found that compared with the same period in 2018 and 2019, the rate of children's influenza activity in 2020 has significantly decreased, which indicates that the protective measures against COVID-19 have effectively reduced the level of influenza activity.

Prevalence and Characteristics of Rheumatoid-Associated Autoantibodies in Patients with COVID-19.

OBJECTIVE: Patients with rheumatic immune diseases were more likely to develop severe or critical COVID-19. We aimed to determine whether rheumatoid factor antibodies were present in COVID patients and the level and type of rheumatoid factor antibodies produced in COVID-19 patients were related to the degree of the patient's condition. The study also aimed to determine the prevalence and characteristics of rheumatoid factor antibodies in patients with COVID-19. METHODS: Sera collected from 129 patients with COVID-19 were tested for rheumatoid factor antibodies by ELISA. Five patients were tracked for several months to monitor dynamic changes of these antibodies. RESULTS: Rheumatoid-associated autoantibodies were detected in 20.16% of patients (26/129) following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In addition, IgM-RF was primarily present in critically ill patients, while IgA-RF was mainly present in mild patients. Five patients were able to track for several months to monitor dynamic changes of these antibodies. Rheumatoid factor antibodies peaks in the later phase of the disease and last for longer time. Anti-Jo-1 antibody was found in one of the five patients. CONCLUSION: This was the case series report that rheumatoid-associated autoantibodies are present in patients with COVID-19. The clinical significance of these antibodies was not fully understood and needed further characterization. These autoantibodies are related to the severity of the patient's disease and exist for a long time in the patient's body, while their impact on the patient's health is unknown.

Serological immunochromatographic approach in diagnosis with SARS-CoV-2 infected COVID-19 patients.

An outbreak of new coronavirus SARS-CoV-2 was occurred in Wuhan, China and rapidly spread to other cities and nations. The standard diagnostic approach that widely adopted in the clinic is nucleic acid detection by real-time RT-PCR. However, the false-negative rate of the technique is unneglectable and serological methods are urgently warranted. Here, we presented the colloidal gold-based immunochromatographic (ICG) strip targeting viral IgM or IgG antibody and compared it with real-time RT-PCR. The sensitivity of ICG assay with IgM and IgG combinatorial detection in nucleic acid confirmed cases were 11.1%, 92.9% and 96.8% at the early stage (1-7 days after onset), intermediate stage (8-14 days after onset), and late stage (more than 15 days), respectively. The ICG detection capacity in nucleic acid-negative suspected cases was 43.6%. In addition, the concordance of whole blood samples and plasma showed Cohen's kappa value of 0.93, which represented the almost perfect agreement between two types of samples. In conclusion, serological ICG strip assay in detecting SARS-CoV-2 infection is both sensitive and consistent, which is considered as an excellent supplementary approach in clinical application.