Interest of screening asymptomatic older adults for SARS-CoV-2 in nursing homes

Importance: Since the beginning of the pandemic, COVID-19 affected specifically elderly people aged 70 years and over in whom the mortality rate is high. We may underestimate asymptomatic people or persons with atypical COVID-19 symptoms who may spread the disease. Objective: A large screening campaign was launched all over France in several retirement homes in order to screen asymptomatic persons for SARS-CoV-2 to isolate carriers from other residents. Methods: From April 24th to 27th 2020, mobile teams of nurses from the Hôtel-Dieu Hospital were sent to five Parisian nursing homes to conduct SARS-CoV-2 RT-PCR screening tests among all asymptomatic. Results: This cross-sectional study included 297 residents: 274 asymptomatic participants (92.3%) were tested for COVID-19, mostly women (n=249/274), median age was 90 (IQR 95% [86-94]) with females being significantly older than males (90 versus 88 years, p= 0.028). A total of 35 residents (12.8%) were tested positive for COVID-19: 29 women (11.7%) and six men (24%). The proportion of PCR-positive residents was extremely variable between retirement homes and analysis of COVID-19 positive cases dispersion in each nursing home showed there was no area cluster. Conclusion: There is a real public health interest in tracking SARS-CoV-2 positive asymptomatic elderly people in nursing homes.

Metabolomic analyses of COVID-19 patients unravel stage-dependent and prognostic biomarkers.

The circulating metabolome provides a snapshot of the physiological state of the organism responding to pathogenic challenges. Here we report alterations in the plasma metabolome reflecting the clinical presentation of COVID-19 patients with mild (ambulatory) diseases, moderate disease (radiologically confirmed pneumonitis, hospitalization and oxygen therapy), and critical disease (in intensive care). This analysis revealed major disease- and stage-associated shifts in the metabolome, meaning that at least 77 metabolites including amino acids, lipids, polyamines and sugars, as well as their derivatives, were altered in critical COVID-19 patient's plasma as compared to mild COVID-19 patients. Among a uniformly moderate cohort of patients who received tocilizumab, only 10 metabolites were different among individuals with a favorable evolution as compared to those who required transfer into the intensive care unit. The elevation of one single metabolite, anthranilic acid, had a poor prognostic value, correlating with the maintenance of high interleukin-10 and -18 levels. Given that products of the kynurenine pathway including anthranilic acid have immunosuppressive properties, we speculate on the therapeutic utility to inhibit the rate-limiting enzymes of this pathway including indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase.

Asymptomatic SARS COV-2 carriers among nursing home staff: A source of contamination for residents?

OBJECTIVES: To show that circulation of SARS-COV-2 in nursing homes in France can come from staff as well as residents' families, whether they are known or not to have had COVID-19. METHODS: This study reports a screening campaign of asymptomatic staff working in elderly nursing homes in Paris where the virus had been circulating actively in March and April 2020. RESULTS: Before the screening campaign, the rate of symptomatic COVID-19 was 23.3% among the residents and 12.1% among their home employees. Within a 72 h screening period, all employees not known to have the virus were screened by RT-PCR in nasopharyngeal swabs. Among the 241 screened employees, 32 (13.3%) tested positive for SARS-CoV-2 on RT-PCR. SARS-CoV-2 carriers and non-carriers did not differ in term of gender, age or type of staff. Staff carrying SARS-CoV-2 were strictly asymptomatic in 75% of cases while during the days following or before the test, 25% presented mild symptoms of COVID-19. Considering both symptomatic and asymptomatic cases, 66 out of 281 (23.5%) of the home employees had been carriers for COVID-19. CONCLUSION: Screening for viral carriage of asymptomatic staff in nursing homes can avoid contact and transmission to frequently severely vulnerable residents.

Elevated Calprotectin and Abnormal Myeloid Cell Subsets Discriminate Severe from Mild COVID-19.

Blood myeloid cells are known to be dysregulated in coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2. It is unknown whether the innate myeloid response differs with disease severity and whether markers of innate immunity discriminate high-risk patients. Thus, we performed high-dimensional flow cytometry and single-cell RNA sequencing of COVID-19 patient peripheral blood cells and detected disappearance of non-classical CD14LowCD16High monocytes, accumulation of HLA-DRLow classical monocytes (Human Leukocyte Antigen - DR isotype), and release of massive amounts of calprotectin (S100A8/S100A9) in severe cases. Immature CD10LowCD101-CXCR4+/- neutrophils with an immunosuppressive profile accumulated in the blood and lungs, suggesting emergency myelopoiesis. Finally, we show that calprotectin plasma level and a routine flow cytometry assay detecting decreased frequencies of non-classical monocytes could discriminate patients who develop a severe form of COVID-19, suggesting a predictive value that deserves prospective evaluation.

Self-reported loss of smell without nasal obstruction to identify COVID-19. The multicenter Coranosmia cohort study.

OBJECTIVES: To determine the frequency of SARS-CoV-2 positive samples in a subset of patients consulting for primarily isolated acute (<7 days) loss of smell and to assess the diagnostic accuracy of olfactory/gustatory dysfunction for COVID-19 diagnosis in the overall population tested for COVID-19 in the same period. METHODS: Prospective multicentric cohort study in four olfactory ENT units and a screening center for COVID-19. RESULTS: i) Among a subset of 55 patients consulting for primarily recent loss of smell, we found that 51 (92.7%) had a COVID-19 positive test (median viral load of 28.8 cycle threshold). Loss of smell was mostly total (anosmia), rarely associated with nasal obstruction but associated with a taste disorder in 80%. Olfactory dysfunction occurred suddenly, either as first complaint or preceded by mild symptoms occurring a median of 3 days. The majority of patients (72.9%) partially recovered the sense of smell within 15 days. ii) In a population of 1824 patients tested for COVID-19, the positive predictive value and the specificity of loss of smell and/or taste were 78.5% and 90.3% respectively (sensitivity (40.8%), negative predictive value (63.6%)). CONCLUSIONS: Self-reported loss of smell had a high predictive positive value to identify COVID-19. Making this sign well known publicly could help to adopt isolation measures and inform potential contacts.