RESUMEN
The SARS-CoV-2 neutralizing antibodies response is the best indicator of effective protection after infection and/or vaccination, but its evaluation requires tedious cell-based experiments using an infectious virus. We analyzed, in 105 patients with various histories of SARS-CoV-2 infection and/or vaccination, the neutralizing response using a virus neutralization test (VNT) against B.1, Alpha, Beta and Omicron variants, and compared the results with two surrogate assays based on antibody-mediated blockage of the ACE2-RBD interaction (Lateral Flow Boditech and ELISA Genscript). The strongest response was observed for recovered COVID-19 patients receiving one vaccine dose. Naïve patients receiving 2 doses of mRNA vaccine also demonstrate high neutralization titers against B.1, Alpha and Beta variants, but only 34.3% displayed a neutralization activity against the Omicron variant. On the other hand, non-infected patients with half vaccination schedules displayed a weak and inconstant activity against all isolates. Non-vaccinated COVID-19 patients kept a neutralizing activity against B.1 and Alpha up to 12 months after recovery but a decreased activity against Beta and Omicron. Both surrogate assays displayed a good correlation with the VNT. However, an adaptation of the cut-off positivity was necessary, especially for the most resistant Beta and Omicron variants. We validated two simple and reliable surrogate neutralization assays, which may favorably replace cell-based methods, allowing functional analysis on a larger scale.
RESUMEN
Rationale: Whether severe coronavirus disease (COVID-19) is a significant risk factor for the development of invasive fungal superinfections is of great medical interest and remains, for now, an open question.Objectives: We aim to assess the occurrence of invasive fungal respiratory superinfections in patients with severe COVID-19.Methods: We conducted the study on patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related pneumonia admitted to five ICUs in France who had respiratory and serum sampling performed for specific screening of fungal complications.Measurements and Main Results: The study population included a total of 145 patients; the median age was 55 years old. Most of them were male (n = 104; 72%), were overweight (n = 99; 68%), and had hypertension (n = 83; 57%) and diabetes (n = 46; 32%). Few patients presented preexisting host risk factors for invasive fungal infection (n = 20; 14%). Their global severity was high; all patients were on invasive mechanical ventilation, and half (n = 73, 54%) were on extracorporeal membrane oxygenation support. Mycological analysis included 2,815 mycological tests (culture, galactomannan, ß-glucan, and PCR) performed on 475 respiratory samples and 532 sera. A probable/putative invasive pulmonary mold infection was diagnosed in 7 (4.8%) patients and linked to high mortality. Multivariate analysis indicates a significantly higher risk for solid organ transplant recipients (odds ratio, = 4.66; interquartile range, 1.98-7.34; P = 0.004). False-positive fungal test and clinically irrelevant colonization, which did not require the initiation of antifungal treatment, was observed in 25 patients (17.2%).Conclusions: In patients with no underlying immunosuppression, severe SARS-CoV-2-related pneumonia seems at low risk of invasive fungal secondary infection, especially aspergillosis.