Upper respiratory tract SARS-CoV-2 RNA loads in symptomatic and asymptomatic children and adults

Costa, Rosa; Bueno, Felipe; Albert, Eliseo; Torres, Ignacio; Carbonell-Sahuquillo, Silvia; Barrés-Fernández, Ana; Sánchez, David Pacheco; Padrón, Carmelo; Colomina, Javier; Carreño, María Isabel Lázaro; Bretón-Martínez, José Rafael; Martínez‐Costa, Cecilia; Navarro, David

doi:10.1016/j.cmi.2021.08.001

Cited by 24 publications

(20 citation statements)

References 36 publications

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“…Patients infected with the Delta variant were significantly more symptomatic (63.3% (61.7-64.8%)) than those infected with the Alpha variant (40.6% (32.3-49.3%)); p < 0.0001 Fisher's exact test) (Table 1). As the NP viral load can vary among asymptomatic and symptomatic patients and overall, depending on the time of NP sampling after symptom onset [8,9], we compared the viral loads of Alpha/Delta and unvaccinated/vaccinated patients according to symptoms and sampling time after symptom onset. The SARS-CoV-2 viral load of symptomatic patients diagnosed within 4 days after the onset of symptoms was significantly greater than that of asymptomatic patients and those diagnosed later, regardless of vaccination status or variant (Figure 1B,C).…”

Section: Resultsmentioning

confidence: 99%

Influence of the Delta Variant and Vaccination on the SARS-CoV-2 Viral Load

Migueres

Trémeaux

Raymond

et al. 2022

Viruses

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Studies comparing SARS-CoV-2 nasopharyngeal (NP) viral load (VL) according to virus variant and host vaccination status have yielded inconsistent results. We conducted a single center prospective study between July and September 2021 at the drive-through testing center of the Toulouse University Hospital. We compared the NP VL of 3775 patients infected by the Delta (n = 3637) and Alpha (n = 138) variants, respectively. Patient’s symptoms and vaccination status (2619 unvaccinated, 636 one dose and 520 two doses) were recorded. SARS-CoV-2 RNA testing and variant screening were assessed by using Thermo Fisher® TaqPath™ COVID-19 and ID solutions® ID™ SARS-CoV-2/VOC evolution Pentaplex assays. Delta SARS-CoV-2 infections were associated with higher VL than Alpha (coef = 0.68; p ≤ 0.01) independently of patient’s vaccination status, symptoms, age and sex. This difference was higher for patients diagnosed late after symptom onset (coef = 0.88; p = 0.01) than for those diagnosed early (coef = 0.43; p = 0.03). Infections in vaccinated patients were associated with lower VL (coef = −0.18; p ≤ 0.01) independently of virus variant, symptom, age and sex. Our results suggest that Delta infections could lead to higher VL and for a longer period compared to Alpha infections. By effectively reducing the NP VL, vaccination could allow for limiting viral spread, even with the Delta variant.

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Section: Resultsmentioning

confidence: 99%

Influence of the Delta Variant and Vaccination on the SARS-CoV-2 Viral Load

Migueres

Trémeaux

Raymond

et al. 2022

Viruses

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“…Some study limitations must be acknowledged: (1) it is uncertain whether the concentration of Spike used in the present work (10 nM) is comparable to those occurring in infected subjects—of note, the viral load of an infected individual varies from 10 2 to 10 13 copies/ml (Costa et al 2021 ) and that the trimeric spike copy number per virion is 26 ± 15 (Yao et al 2020 ): the highest figures should generate in vivo a Spike concentration around 2–7 nM; (2) although our data are compatible with a role of Spike glycosylation in macrophage inflammation, future ad hoc experiments should be performed to prove a causal relationship; (3) the extrapolation of our in vitro data to the complex in vivo setting should be made with caution.…”

Section: Discussionmentioning

confidence: 99%

SARS-CoV-2 Spike protein is not pro-inflammatory in human primary macrophages: endotoxin contamination and lack of protein glycosylation as possible confounders

et al. 2022

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Introduction The inflammatory potential of SARS-CoV-2 Spike S1 (Spike) has never been tested in human primary macrophages (MΦ). Different recombinant Spikes might display different effects in vitro, according to protein length and glycosylation, and endotoxin (lipopolysaccharide, LPS) contamination. Objectives To assess (1) the effects of different Spikes on human primary MΦ inflammation; (2) whether LPS contamination of recombinant Spike is (con)cause in vitro of increased MΦ inflammation. Methods Human primary MΦ were incubated in the presence/absence of several different Spikes (10 nM) or graded concentrations of LPS. Pro-inflammatory marker expression (qPCR and ELISA) and supernatant endotoxin contamination (LAL test) were the main readouts. Results LPS-free, glycosylated Spike (the form expressed in infected humans) caused no inflammation in human primary MΦ. Two (out of five) Spikes were contaminated with endotoxins ≥ 3 EU/ml and triggered inflammation. A non-contaminated non-glycosylated Spike produced in E. coli induced MΦ inflammation. Conclusions Glycosylated Spike per se is not pro-inflammatory for human MΦ, a feature which may be crucial to evade the host innate immunity. In vitro studies with commercially available Spike should be conducted with excruciating attention to potential LPS contamination. Graphical abstract

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“…Aykaç et al detected no difference in viral loads between clinical courses in children. 11 Another study reported higher viral loads in asymptomatic children (p > 0.05) 19 while in contradiction, Kociolek et al reported higher viral loads in symptomatic children (p < 0.001). 20 The discrepancy between different studies may depend on the time the sample was taken.…”

Section: Discussionmentioning

confidence: 96%

The Impact of Alpha Variant (B.1.1.7), Viral Load, and Age on the Clinical Course of Pediatric COVID-19 Patients

Unalan-Altintop

Celep

Milletli-Sezgin

et al. 2022

J Pediatr Infect Dis

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Objective The research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mainly consists of adult patients, leaving its impact on children understudied. This study aims to investigate the correlations between viral load, clinical course, age, and Alpha variant (B.1.1.7) in children. Methods The study was conducted on children under the age of 18 years, who were admitted to Amasya University Sabuncuoglu Serefeddin Research and Training Hospital in Turkey between February and April 2021. ΔCt values, which were obtained by real-time polymerase chain reaction (PCR), were analyzed to estimate the viral loads of the patients. Alpha variant (B.1.1.7) positivity was determined by real-time PCR. Results There was no difference between estimated viral loads of different clinical courses (p > 0.05), or between asymptomatic and symptomatic patients (p > 0.05). Viral loads were found to decrease with increasing age (p = 0.002). Also, a higher rate of symptomatic disease was found in children under the age of 4 years (p < 0.05). Alpha variant (B.1.1.7) was not found to be associated with severe disease in children (p > 0.05). Conclusion Our results demonstrate higher viral loads and symptomatic disease in children under the age of 4 years. Alpha variant (B.1.1.7) was not found to be related to disease severity. There has not been a consensus on the vaccination of the pediatric population worldwide. More studies are needed to understand the viral kinetics of SARS-CoV-2 and its severity on children to build effective vaccination strategies in children as public health restrictions are eased.

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Upper respiratory tract SARS-CoV-2 RNA loads in symptomatic and asymptomatic children and adults

Cited by 24 publications

References 36 publications

Influence of the Delta Variant and Vaccination on the SARS-CoV-2 Viral Load

Influence of the Delta Variant and Vaccination on the SARS-CoV-2 Viral Load

SARS-CoV-2 Spike protein is not pro-inflammatory in human primary macrophages: endotoxin contamination and lack of protein glycosylation as possible confounders

The Impact of Alpha Variant (B.1.1.7), Viral Load, and Age on the Clinical Course of Pediatric COVID-19 Patients

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