Study says severity of COVID-19 infection can be predicted by amount of viral RNA in patient's body

The study found that patients with high viral load are at increased risk of having severe symptoms and their risk of dying or being intubated is twice that of the patients with less viral load irrespective of their age, comorbidities and severity of illness

Myupchar October 30, 2020 21:51:46 IST
Study says severity of COVID-19 infection can be predicted by amount of viral RNA in patient's body

Representational image. Mufid Majnun/Unsplash

SARS-CoV-2, the novel coronavirus that causes COVID-19, is known to present itself differently in every individual. While some COVID-19 patients experience mild or no symptoms, others may go on to suffer from severe respiratory distress and organ damage. So far, the severity of COVID-19 disease has been associated with old age or pre-existing illnesses that the patient might have. However, according to a recent study published in the journal Annals of the American Thoracic Society on 29th October 2020, it was found that the amount of viral RNA in a patient’s body at the time of admission to the hospital could determine their probability of getting severe symptoms.

Calculating the viral RNA to determine the risk of COVID-19 severity

For this study, scientists from the Department of Medicine at the New York University Grossman School of Medicine examined the medical records of 314 COVID-positive patients who were admitted to the NYU Langone Health emergency room between 31st March 2020 and 10th April 2020 due to severe viral pneumonia.

The median age of these patients was 64 years. Out of these 314 patients, 205 were male, 117 were obese (with a body mass index of 30 or above), 50 patients had at least one previously diagnosed pulmonary condition, 72 were active or former smokers, 21 had undergone transplant surgery and 4 had HIV (Human Immunodeficiency Virus).

The scientists calculated the comorbidities and the severity of pneumonia during admission with the help of the Charlson Comorbidity Index (CCI) and the Pneumonia Severity Index (PSI).

The patients were divided into five different classes based on their PSI score.

In order to determine the viral load in these patients, the scientists used cycle threshold value (CT value), which helps in determining the amount of viral RNA in a person’s body and is equivalent to the amount of viral load detected on nasopharyngeal swabs. For instance, a CT value of 23 means that only 23 cycles of amplification were needed for the detection of DNA. The more cycles required, the less viral load is present in the body.

The CT values were divided into 3 categories:

1. Low: CT value more than or equal to 34.2

2. Intermediate: CT value between 27.7 and 34.2

3. High: CT value less than or equal to 27.7.

The endpoint of the study was to find out the number of patients who required mechanical ventilation or extracorporeal membrane oxygenation (ECMO), who were discharged to hospice care and who died.

Results of the study

The results of the study showed that out of the 314 patients, 107 presented with low CT value, 103 showed intermediate CT value and 104 presented with high CT value.

It was also found that patients who had a low CT value also showed higher CCI and PSI scores.

Scientists found that most of these patients with high PSI and CCI score were transplant recipients and presented with a shorter duration of symptoms.

It was revealed that patients with a high viral load during hospital admission were at an increased risk of needing intubation or ECMO or death.

Conclusion

The scientists concluded that patients with a high comorbidity index and shorter duration of symptoms are more likely to have high SARS-CoV-2 viral load at the time of hospital admission.

It was further concluded that these patients with high viral load are at increased risk of having severe symptoms and their risk of dying or being intubated is twice that of the patients with less viral load irrespective of their age, comorbidities and severity of illness during hospital admission.

For more information, read our article on Mild versus severe symptoms of COVID-19

Health articles in Firstpost are written by myUpchar.com, India’s first and biggest resource for verified medical information. At myUpchar, researchers and journalists work with doctors to bring you information on all things health.

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