Amount of COVID Viral RNA Detected at Hospital Admission Predicts How Patients Will Fare

A new study published online at Annals of the American Thoracic Society examines whether the amount of SARS-CoV-2 RNA, or genomic load, detected in smear tests from patients admitted to hospital with viral pneumonia is associated with more severe COVID-19. SARS-CoV-2 is the virus that causes COVID-19. Previous studies on this question have had conflicting results.

In “Association of SARS-CoV-2 Genomic Load With COVID-19 Patient Outcomes,” Ioannis M. Zacharioudakis, MD, infectious disease specialist in the Department of Medicine at New York University Grossman School of Medicine, and the Co-authors analyzed the medical records of 314 patients who came to the NYU Langone Health emergency room between March 31 and April 10, 2020, diagnosed with COVID-19 in a molecular diagnostic test (RT-PCR) who also had viral pneumonia severe enough to require hospitalization. This research was conducted as a retrospective cohort study, following previous patients who had common characteristics.

“We show that for patients admitted to hospital with COVID-19 pneumonia, the burden of SARS-CoV-2, as reflected in the CRP cycle threshold (Ct) value, should be considered as a predictor of adverse outcomes, “said Dr. Zacharioudakis. “A high viral load has been shown to be a predictor of unfavorable outcomes beyond age, other medical problems, and disease severity at presentation, indicating that it can be used to stratify risk or rank the patients”.

Real-time reverse transcriptase polymerase chain reaction (RT-PCR) tests for SARS-CoV-2 are the most accurate class of COVID tests available today, and can sample and analyze the largest amount of material genetic, even in presymptomatic stages of the disease. In this study, respiratory samples that were analyzed using RT-PCR technology were obtained from patients using nasopharyngeal swabs, the long swabs that are widely used in healthcare settings, as well as at public testing sites.

A cycle threshold value is one of the results that the PCR technique provides and can be used as a surrogate for the amount of virus that is detected in nasopharyngeal swabs. Since the Ct value is obtained from most commercial RT-PCR testing platforms, it can be a readily available tool for the provider to help risk stratify and classify hospitalized patients with COVID pneumonia. -19.

The researchers determined that the study endpoints would include whether a patient required mechanical ventilation or extracorporeal membrane oxygenation (ECMO) and whether the patient died while in hospital or was discharged from hospice. Statistical calculations were performed to determine how often patients with high versus low viral load met endpoints after adjusting for concurrent patient conditions (comorbidities) using the Charlson comorbidity index and pneumonia severity in the time of presentation. , as shown in the Pneumonia Severity Index.

“We know that the virus multiplies rapidly in the asymptomatic and early symptomatic stages of COVID-19,” said Dr. Zacharioudakis. “Our study is in line with this conclusion, as indicated by our finding of a higher viral load in patients with earlier disease.”

He added: “The study also found that patients who had multiple comorbid conditions, such as heart disease, diabetes and cancer, or who were immunosuppressed due to a solid organ transplant, were more likely to have a higher SARS-CoV-2 burden. discharge from hospital, admission and as a result an increased risk of poor outcomes. “

An important feature of this study was that it focused on patients who required hospital admission for COVID-19 pneumonia, a group that is at high risk of serious illness or death. The fact that the association of high viral load with poor patient outcomes was maintained after taking into account the underlying conditions of the patients, how long they were ill before arriving at the hospital, and how ill they were at the time of presented adds valuable evidence demonstrating the ability of SARS-CoV-2 viral load to predict COVID outcomes.

The authors note that, among patients with a severe clinical presentation, those with a high SARS-CoV-2 viral load were almost twice as likely to be intubated or die.

Dr Zacharioudakis added: “Our study provides a rationale for using the SARS-CoV-2 burden of patients at the time of hospital admission to assess their risk of adverse outcomes. In an era where the availability of antiviral drugs that have been shown to be effective against COVID could be limited and the capacity for intensive follow-up is finite, it is of utmost importance to be able to prioritize patients who will benefit more from early treatment or a higher level of care. More studies are needed to assess whether a decrease in viral load in hospitalized COVID-19 patients, who may or may not be treated with antiviral drugs such as Remdesivir, correlate with an improvement in clinical status. ”