Immunologic features of asymptomatic postvaccination infections with the Delta variant of SARS-CoV-2 in adults.

BACKGROUND: Asymptomatic infections may play an important role in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Delta variant transmissions. However, the immunologic features of asymptomatic postvaccination infections with the Delta variant of SARS-CoV-2 in adults remain to be defined. METHODS: A retrospective study involving 36 vaccinated adults infected with the SARS-CoV-2 Delta variant was performed. Their demographic and laboratory data were collected and analyzed in The First People's Hospital of Jingmen from August 4 to 20, 2021. RESULTS: Of the 36 adults, 6 persons had an asymptomatic infection. The severity of the SARS-CoV-2 infections was highly correlated with the doses of vaccinations (p = 0.019). The symptomatic and asymptomatic infected SARS-CoV-2 adults showed normal levels of leukocytes and lymphocytes. The C-reactive protein (CRP) and interleukin-6 (IL-6) levels were elevated in the symptomatic groups. The period between the last vaccination to the time of infection in the asymptomatic group was longer than that in the mild and moderate groups (73 vs. 61 vs. 50 days; p = 0.047). The percentage of suppressor T-cells in the asymptomatic group was the highest (32.2 ± 4.0% vs. 22.0 ± 7.2% vs. 29.3 ± 8.0%; p = 0.004). The signal-to-cutoff ratio value of total antibody against SARS-CoV-2 in the asymptomatic group was lower than that in the other two groups (383 vs. 703 vs. 1792; p < 0.001) and much lower than that in the moderate group. The multivariate ordinal logistic analysis after adjusting for gender, vaccination date, and vaccination dose indicated that CRP at Days 4-7 and 8-14, IL-6 on Days 4-7, and total antibody were risk factors for coronavirus disease 2019 severity. CONCLUSIONS: Asymptomatic postvaccination infections with the Delta variant of SARS-CoV-2 in adults tend to infect persons vaccinated twice. The immunophenotype profile for asymptomatic postvaccination infections is less inflammatory and accompanied by relatively lower antibody titers.

Clinical and laboratory features in COVID-19 patients without anti-SARS-CoV-2 antibody

Objective: The aim of this study is to investigate the clinical and laboratory features in confirmed COVID-19 patients without specific anti-SARS-CoV-2 antibody,it is important to interpret SARS-CoV-2 antibody test results correctly and provide effective management for COVID-19 patients without specific anti-SARS-CoV-2 antibody.

Malaria Surveillance of Entry People During the COVID-19 Epidemic - Guangdong Province, China, October 2020-May 2021.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Malaria control was affected by the coronavirus disease 2019 (COVID-19) pandemic. This study conducted active case finding for key flights and key populations to determine malaria transmission. WHAT IS ADDED BY THIS REPORT?: Surveillance for malaria was conducted for entry personnel coming from areas affected by malaria. It is estimated that at least 100,000 tests were conducted in Guangdong Province; 154 cases were confirmed during the surveillance. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: To maintain the malaria elimination status, comprehensively maintaining a sensitive and effective surveillance response system is especially important.

Characteristics of lymphocyte subsets and cytokines in peripheral blood of 123 hospitalized patients with 2019 novel coronavirus pneumonia (NCP) (preprint)

Background: To explore the cellular immunity and cytokines status of NCP patients and to predict the correlation between the cellular immunity levels, cytokines and the severity of patients. Methods: 123 NCP patients were divided into mild and severe groups. Peripheral blood was collected, lymphocyte subsets and cytokines were detected. Correlation analysis was performed on the lymphocyte subsets and cytokines, and the differences between the indexes of the two groups were analyzed. Results: 102 mild and 21 severe patients were included. Lymphocyte subsets were reduced in two groups. The proportion of CD8 + T reduction in the mild and severe group was 28.43% and 61.9%, respectively; The proportion of B cell reduction was 25.49% and 28.57%; The proportion of NK cell reduction was 34.31% and 47.62%; The detection value of IL-6 was 0 in 55.88% of the mild group, mild group has a significantly lower proportion of patients with IL-6 higher than normal than severe group; There was no significant linear correlation between the lymphocyte subsets and cytokines, while significant differences were noticed between the two groups in CD4 + T, CD8 + T, IL-6 and IL-10. Conclusions: Low levels of CD4+T and CD8+T are common in severe NCP. IL-6 and IL-10 levels were higher in severe patients. T cell subsets and cytokines can be used as one of the basis for predicting the transition from mild to severe. Large number of samples are still needed to confirm the "warning value" of CD4 + T, CD8 + T IL-6 and IL-10.