Association of SARS-CoV-2 cycle threshold (Ct) values with clinical course and serum biomarkers in COVID-19 patients

Abstract

Introduction: Our knowledge has gaps regarding severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication levels and its association to severity of Coronavirus disease 2019 (COVID-19). The aim of this study was to investigate the association of SARS-CoV-2 viral load with disease severity and serum biomarkers in COVID-19 patients.
 Methodology: Viral load was determined via cycle threshold (Ct) values of SARS-CoV-2 real-time reverse transcriptase-polymerase chain reaction (RT-PCR) in 214 adult patients. Ct values were compared with clinical severity, biochemical and hematological biomarkers.
 Results: Clinical course of the disease was mild (49.1%), moderate (40.2%), and severe (10.7%). Median Ct value was 28.2 (IQR: 22.2–33.8) during the first week of the disease. Ct values were lower within five days after symptom onset [lowest Ct value on the third day (median: 24, IQR: 20.6–32.3)], but they increased significantly during the second and third weeks. No association was detected between admission Ct values and disease severity. Gender, age, co-morbidity, and mortality did not differ significantly in patients with low (≤ 25) and high (> 25) Ct values. White blood cell, neutrophil, platelet, and especially lymphocyte counts, were significantly lower in patients with low Ct values.
 Conclusions: No definitive/clear correlation between SARS-CoV-2 viral load and severity and mortality was found in the studied COVID-19 patients. However, neutrophil, platelet, and especially lymphocyte count were significantly lower in patients with a high viral load.

Low SARS-CoV-2 Cq values in healthcare workers with symptomatic COVID-19 infections, regardless of symptom severity, The Netherlands, January to August 2022

“…Cq values above 30 are generally assumed to yield little culturable virus [ 5 , 6 ]. The majority of HCW in our study were considered infectious at the time of testing, and symptom severity alone could not be a reliable indicator of infectiousness, which is in line with observations in the literature [ 7 , 8 ].…”

The Importance of SARS CoV 2 RT-PCR Positivity and Hematologic Parameters in COVID-19 Patients

“…Öte yandan Sağlık ve ark. 'nın (27) yaptığı bir çalışmada, hastaların cinsiyeti, komorbiditesi ve mortalitesi üzerinde bir ilişkinin olmadığı görülmüştür. Çalışmamızda, buna benzer olarak, servis ve yoğun bakım COVID-19 PCR değerleri arasında istatistiksel açıdan anlamlı fark bulunmamıştır (p=0.068).…”

“…Onder ve ark. 'nın (29) İtalya'da yaptıkları bir çalışmada, COVID-19 hastalarında mortalite oranının yaşla birlikte arttığı gözlemlenmiş iken, bir başka çalışmada Ct değerleri ile hastaların yaşı arasında bir ilişkinin olmadığı görülmüştür (27) . Çalışmamızda, serviste yatan kadınların yaş aralığı 17-86 yaş iken, erkeklerde SARS CoV-2 insanda edinsel ve doğal immun sistem hücrelerini direk olarak hasara uğratarak, kemokinler veya sitokinler yoluyla etkilemektedir (11,12) .…”

“…Sağlık ve ark. 'nın (27) yaptıkları bir çalışmada, yüksek viral yükü olan hastalarda düşük notrofil, lenfosit ve trombosit sayıları bulunmuştur. Çalışmamızda ise yoğun bakımda yatan hastalarda serviste yatan hastalara göre lökosit ve nötrofil sayısında anlamlı değişiklik saptanmazken (p=0.300 ve p=0.465), lenfosit sayısının düşük (p<0.01) olduğunu bulduk.…”

Association between the overall burden of comorbidity and Ct values among the older patients with Omicron infection: Mediated by inflammation

“…Furthermore, the correlation of respiratory viral loads were found to be correlated with inflammatory indicators in the plasma of elderly patients ( 24 ). White blood cells, neutrophils, and lymphocytes were significantly lower in patients with a high viral load (Ct ≤ 25) ( 25 ). Considering these results, the associations between Ct values and the preexisting comorbidities might be affected by inflammation.…”