Resistance of SARS-CoV-2 variants to neutralization by antibodies induced in convalescent patients with COVID-19.

Administration of convalescent plasma or neutralizing monoclonal antibodies (mAbs) is a potent therapeutic option for coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, SARS-CoV-2 variants with mutations in the spike protein have emerged in many countries. To evaluate the efficacy of neutralizing antibodies induced in convalescent patients against emerging variants, we isolate anti-spike mAbs from two convalescent COVID-19 patients infected with prototypic SARS-CoV-2 by single-cell sorting of immunoglobulin-G-positive (IgG+) memory B cells. Anti-spike antibody induction is robust in these patients, and five mAbs have potent neutralizing activities. The efficacy of most neutralizing mAbs and convalescent plasma samples is maintained against B.1.1.7 and mink cluster 5 variants but is significantly decreased against variants B.1.351 from South Africa and P.1 from Brazil. However, mAbs with a high affinity for the receptor-binding domain remain effective against these neutralization-resistant variants. Rapid spread of these variants significantly impacts antibody-based therapies and vaccine strategies against SARS-CoV-2.

Decrease in hemoglobin level predicts increased risk for severe respiratory failure in COVID-19 patients with pneumonia.

BACKGROUND: In December 2019, the coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), emerged in Wuhan, China, and has since spread throughout the world. This study aimed to investigate the association between the change in laboratory markers during the three days after pneumonia diagnosis and severe respiratory failure in COVID-19 patients. METHODS: Data of 23 COVID-19 patients with pneumonia, admitted to the Kumamoto City Hospital between February and April 2020 were retrospectively analyzed. RESULTS: Among the 23 patients, eight patients received mechanical ventilation (MV) (MV group), and the remaining 15 comprised the non-MV group. The levels of hemoglobin (Hb) and albumin (Alb) decreased in the MV group during the three days after pneumonia diagnosis more than in the non-MV group (median Hb: 1.40 vs. -0.10 g/dL, P = 0.015; median Alb: 0.85 vs. -0.30 g/dL, P = 0.020). Univariate logistic regression analysis showed that the decrease in Hb was associated with receiving MV care (odds ratio: 0.313, 95% confidence interval: 0.100-0.976, P = 0.045). Receiver operating characteristic curve analyses showed that the optimal cut-off value for the decrease in Hb level was -1.25 g/dL, with sensitivity and specificity values of 0.867 and 0.750, respectively. CONCLUSIONS: The decrease in Hb level during the short period after pneumonia diagnosis might be a predictor of worsening pneumonia in COVID-19 patients.

Importation of dengue virus type 3 to Japan from Tanzania and Cote d'Ivoire.

Travelers can introduce viruses from disease-endemic to non-disease-endemic areas. Serologic and virologic tests confirmed dengue virus infections in 3 travelers returning to Japan: 2 from Tanzania and 1 from Cote d'Ivoire. Phylogenetic analysis of the envelope gene showed that 2 genetically related virus isolates belonged to dengue virus type 3 genotype III.