The emergence of SARS-CoV-2 variants with mutations in the spike protein is raising concerns about the efficacy of infection-or vaccine-induced antibodies. We compared antibody binding and live virus neutralization of sera from naturally infected and Moderna-vaccinated individuals against two SARS-CoV-2 variants: B.1 containing the spike mutation D614G and the emerging B.1.351 variant containing additional spike mutations and deletions. Sera from acutely infected and convalescent COVID-19 patients exhibited a 3-fold reduction in binding antibody titers to the B.1.351 variant receptor-binding domain of the spike protein and a 3.5-fold reduction in neutralizing antibody titers against SARS-CoV-2 B.1.351 variant compared to the B.1 variant. Similar results were seen with sera from Moderna-vaccinated individuals. Despite reduced antibody titers against the B.1.351 variant, sera from infected and vaccinated individuals containing polyclonal antibodies to the spike protein could still neutralize SARS-CoV-2 B.1.351, suggesting that protective humoral immunity may be retained against this variant.

Background The increasing global prevalence of pulmonary nontuberculous mycobacteria (NTM) disease has called attention to challenges in NTM diagnosis and management. This study is conducted to understand management and outcomes of patients with pulmonary NTM disease at diverse centers across the US. Methods We conducted a 10-year (2005-2015) retrospective study at seven Vaccine and Treatment Evaluation Units to evaluate pulmonary NTM treatment outcomes in human immunodeficiency virus-negative adults. Demographic and clinical information were abstracted through medical record review. Microbiologic and clinical cure were evaluated using previously defined criteria. Results Of 297 patients diagnosed with pulmonary NTM, the most frequent NTM species were Mycobacterium avium-intracellulare complex (83.2%), M. kansasii (7.7%), and M. abscessus (3.4%). Two hundred forty-five (82.5%) patients received treatment, while 45 (15.2%) were followed without treatment. Eighty-six patients had available drug susceptibility results; of these, >40% exhibited resistance to rifampin, ethambutol, or amikacin. Of the 138 patients with adequate outcome data, 78 (56.5%) experienced clinical and/or microbiologic cure. Adherence to the American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) treatment guidelines was significantly more common in patients who were cured (odds ratio [OR] 4.5, 95% confidence interval [CI] 2.0-10.4, P < 0.001). Overall mortality was 15.7%. Conclusions Despite ATS/IDSA Guidelines, management of pulmonary NTM disease was heterogeneous and cure rates were relatively low. Further work is required to understand which patients are suitable for monitoring without treatment and the impact of antimicrobial therapy on pulmonary NTM morbidity and mortality.

The emergence of SARS-CoV-2 variants with mutations in the spike protein is raising concerns about the efficacy of infection- or vaccine-induced antibodies to neutralize these variants. We compared antibody binding and live virus neutralization of sera from naturally infected and spike mRNA vaccinated individuals against a circulating SARS-CoV-2 B.1 variant and the emerging B.1.351 variant. In acutely-infected (5-19 days post-symptom onset), convalescent COVID-19 individuals (through 8 months post-symptom onset) and mRNA-1273 vaccinated individuals (day 14 post-second dose), we observed an average 4.3-fold reduction in antibody titers to the B.1.351-derived receptor binding domain of the spike protein and an average 3.5-fold reduction in neutralizing antibody titers to the SARS-CoV-2 B.1.351 variant as compared to the B.1 variant (spike D614G). However, most acute and convalescent sera from infected and all vaccinated individuals neutralize the SARS-CoV-2 B.1.351 variant, suggesting that protective immunity is retained against COVID-19.

This study reports enhanced light harvesting in an ultrathin Q-CdTe/Se quantum dot layer sensitized TiO 2 photonic crystal that is enabled by light trapping which increases light absorbance in the photonic crystal structure. We fabricated TiO 2 inverse opals (i-TiO 2 -o) with stop bands centered at ca. 550 nm (550-i-TiO 2 -o) sensitized with 2−4 nm Q-CdTe with absorption edges tuned to the red, within, and to the blue of the stop band, followed by surface modification with Se. The photoelectrode behavior was examined in the presence of an alkaline selenide electrolyte which enhances stability and efficiency, relative to the usual sulfide electrolyte. Modification with Se resulted in type-II Q-CdTe/CdSe characteristics of enhanced red-shifted absorbance and quenched emission, and a major increase in the light-to-current conversion was measured on both nc-TiO 2 and i-TiO 2 -o after annealing attributed to improved charge separation across the Q-CdTe/CdSe interface. A 4-fold amplification was measured on average for i-TiO 2 -o sensitized with green-emitting 2.3 nm Q-CdTe to both the blue and red of the stop band relative to similarly sensitized nonscattering nc-TiO 2 , before and after Se-modification, which is attributed to light trapping amplifying absorbance. The gain is shown to depend on the absorption edge relative to the stop band; a smaller gain was measured for i-TiO 2 -o sensitized with 3 nm yellow-emitting Q-CdTe with an absorbance edge within the stop band. An enhancement by 4−5 fold in the overall visible photonto-current-conversion efficiency resulted at i-TiO 2 -o sensitized with green-Q-CdTe/CdSe relative to similarly modified nc-TiO 2 : about 2-fold is attributed to the type-II structure and 2-fold to light trapping in the photonic crystal enhancing light absorbance by the layer of quantum dots.