Viral load decides Covid mortality in patients with or without cancer, US study shows

Study finds that chance of mortality from Covid-19 goes up as the viral load increases, and this holds true even for patients with comorbidities.

Representational image of a suspected Covid-19 patient being taken in an ambulance | ANI

New Delhi: As countries grapple with the unpredictable outcomes of Covid-19 in patients, a US study has concluded that viral load may hold the key to whether a person survives the infection.

The pre-print study, submitted to the journal Cancer Cell, was conducted by the NewYork-Presbyterian Hospital, Weill Cornell Medical Center and Columbia University, on Covid-19 patients who had cancer and those who did not. And the outcomes were similar in both sets of patients, with viral load having a direct impact on mortality.

Viral load refers to the amount of virus found in each unit of a sample. In an RT-PCR test, for example, the number of cycles that are run before the virus is detected give a measure of the viral load — the lower the number of cycles, the higher the viral load.

“Overall, the in-hospital mortality rate was 38.8 per cent among patients with a high viral load, 24.1 per cent among patients with a medium viral load, and 15.3 per cent among patients with a low viral load. Similar findings were observed in patients with cancer (high, 45.2 per cent mortality; medium, 28.0 per cent; low, 12.1 per cent),” the researchers reported.

They said it was important to highlight viral load in Covid patients’ test reports, to enable doctors to take the right calls on their treatment.

“As a community, we’ve only begun to understand the relationship between SARS-CoV-2 viral load and outcomes. Currently, this quantitative information is not given to patient care teams, and providers only know if a patient’s test is positive or negative,” Michael Satlin, senior author of the study, said in a statement.

Satlin, assistant professor of medicine in the Division of Infectious Diseases at Weill Cornell Medicine and an assistant attending physician at NewYork-Presbyterian/Weill Cornell Medical Center, added: “Giving this information to providers of patients with cancer who have Covid-19 could help them decide on which patients should receive more intensive monitoring when they are in the hospital and which should receive new antiviral medicines if these treatments are in short supply.”

Methodology

The study looked at 100 Covid-19 patients with cancer and 2,914 without cancer who were admitted to three New York City hospitals.

The researchers reported: “…we found that admission viral load not only correlates with in-hospital mortality overall, but is also associated with in-hospital mortality among patients with active cancer. In fact, admission viral load was an independent predictor of in-hospital mortality in patients with cancer even after adjusting for important confounders such as age and hypoxia upon arrival to the ED (emergency department).”

Last month, a study in The Lancet too had said there is a definite correlation between viral load and Covid mortality, but this new study has established that viral load as a predictor of outcome could be independent even of existing comorbidities.

Patients with haematologic (blood related) malignancies had higher viral loads than in patients of other kinds of cancer.

“We suspect that this finding may be from the underlying immunodeficiencies conferred by either the hematologic malignancies or the administered therapies, which may decrease the ability to inhibit proliferation of SARS-CoV-2,” said co-first author Lars Westblade, referring to the fact that many cancer treatments such as chemotherapies leave patients immunocompromised.

Westblade, associate professor of pathology and laboratory medicine at Weill Cornell Medicine and a clinical microbiologist at NewYork-Presbyterian/Weill Cornell Medical Center, added: “Additional studies with a larger sample size of patients with haematologic malignancies are needed to more definitely assess whether these patients have increased mortality when hospitalised with Covid-19.”