SARS-CoV-2 viral load in nasopharyngeal swabs is not an independent predictor of unfavorable outcome

Abstract

The aim was to assess the ability of nasopharyngeal SARS-CoV-2 viral load at first patient’s hospital evaluation to predict unfavorable outcomes. We conducted a prospective cohort study including 321 adult patients with confirmed COVID-19 through RT-PCR in nasopharyngeal swabs. Quantitative Synthetic SARS-CoV-2 RNA cycle threshold values were used to calculate the viral load in log10 copies/mL. Disease severity at the end of follow up was categorized into mild, moderate, and severe. Primary endpoint was a composite of intensive care unit (ICU) admission and/or death (n = 85, 26.4%). Univariable and multivariable logistic regression analyses were performed. Nasopharyngeal SARS-CoV-2 viral load over the second quartile (≥ 7.35 log10 copies/mL, p = 0.003) and second tertile (≥ 8.27 log10 copies/mL, p = 0.01) were associated to unfavorable outcome in the unadjusted logistic regression analysis. However, in the final multivariable analysis, viral load was not independently associated with an unfavorable outcome. Five predictors were independently associated with increased odds of ICU admission and/or death: age ≥ 70 years, SpO2, neutrophils > 7.5 × 103/µL, lactate dehydrogenase ≥ 300 U/L, and C-reactive protein ≥ 100 mg/L. In summary, nasopharyngeal SARS-CoV-2 viral load on admission is generally high in patients with COVID-19, regardless of illness severity, but it cannot be used as an independent predictor of unfavorable clinical outcome.

Plasma SARS-CoV-2 nucleocapsid antigen levels are associated with progression to severe disease in hospitalized COVID-19

“…Viral burden in SARS-CoV-2 infection is most often quantified by measurement of viral RNA or proteins in the upper respiratory tract. Higher viral load in the upper respiratory tract portends worse outcomes in some studies [7][8][9][10], while others have demonstrated no independent association [11]. Viral load in the upper airways is often not strongly associated with viral products in the plasma [12][13][14][15].…”

COVID‐19 outcomes in children, adolescents and young adults with cancer

“… 27 , 28 Given the need for prognostic biomarkers in COVID‐19, several studies have investigated the value of PCR C t , a surrogate measure of viral load, as an outcome predictor in COVID‐19 in the general population. However, varying data ranging from no prognostic value to being a risk factor for mortality have been reported for PCR C t in adults with COVID‐19; 29 , 30 , 31 C t value criteria for demarcation between low and high viral loads remain to be defined. 29 To our knowledge, our study represents the first report of an association between low C t and hospitalization in COVID‐19 in pediatric cancer.…”

“…However, varying data ranging from no prognostic value to being a risk factor for mortality have been reported for PCR C t in adults with COVID‐19; 29 , 30 , 31 C t value criteria for demarcation between low and high viral loads remain to be defined. 29 To our knowledge, our study represents the first report of an association between low C t and hospitalization in COVID‐19 in pediatric cancer. Our results raise the need for further prospective studies investigating C t as a potential biomarker for predicting outcomes in COVID‐19 in pediatric cancer.…”

Is SARS‐CoV‐2 viral clearance in nasopharyngeal swabs an appropriate surrogate marker for clinical efficacy of neutralising antibody‐based therapeutics?

“…7,8 Viral load may correlate with infectivity, disease phenotype and morbidity in COVID-19 patients, although a higher initial SARS-CoV-2 viral load was associated with increased risk of hospital admission, intensive care unit (ICU) admission and in-hospital mortality in some 9 but not in other studies. 10 Nonetheless, SARS-CoV-2 viral load at diagnosis was an independent predictor of mortality in a large, hospitalised cohort study (hazard ratio 1.07, with a 7% increase in hazard for each log transformed copy per millilitre). 11 A hallmark of effective antiviral therapy is its ability to reduce the viral burden, as evidenced by anti-viral drug therapy for HIV, HCV and herpesviruses.…”

“…Although PCR can also detect non‐infectious, immune‐complexed viral particles, the correlation of viral load in NPS with infectious SARS‐CoV‐2 has been established in large studies 7,8 . Viral load may correlate with infectivity, disease phenotype and morbidity in COVID‐19 patients, although a higher initial SARS‐CoV‐2 viral load was associated with increased risk of hospital admission, intensive care unit (ICU) admission and in‐hospital mortality in some 9 but not in other studies 10 . Nonetheless, SARS‐CoV‐2 viral load at diagnosis was an independent predictor of mortality in a large, hospitalised cohort study (hazard ratio 1.07, with a 7% increase in hazard for each log transformed copy per millilitre) 11 …”