The New York Times posted today a summary of the findings of multiple studies of the association between the amount of “viral load” of SARS-CoV-2 and the severity of disease and mortality from COVID-19.
Not surprisingly, the correlation is very strong. This is entirely consistent with our general understandings of how viral infections progress, and how antibodies work to combat them. Here are some of the journal references:
- Association of SARS-CoV-2 Genomic Load with COVID-19 Patient Outcomes (ATS Journal)
- High SARS-CoV-2 viral load is associated with a worse clinical outcome of COVID-19 disease (BMJ, Yale, CSH on MedRXiv)
- SARS-CoV-2 viral load is associated with increased disease severity and mortality (Nature)
- SARS-CoV-2 viral load predicts COVID-19 mortality (The Lancet)
- In vivo antiviral host response to SARS-CoV-2 by viral load, sex, and age (Cold Spring Harbor Labs in BioRXiv)
We certainly understand that from a pure science perspective we need to prove each and every hypothesis with data. But we ask all public health leaders and physicians, from a medical perspective, isn’t there an imperative to use a reasonable working hypothesis, factoring in known, unknowns and previous experience to arrive at a course of treatment? Isn’t that in fact how every case and patient is handled? Why should it not be so at the macro scale during an epidemic? These studies bring data to prove what was already a reasonable working hypothesis based on a very large body of experience with viruses.
Tracking viral loads “can actually help us stratify risk,” Dr. Griffin said. The idea is not new: Managing viral load has long formed the basis of care for people with H.I.V., for example, and for tamping down transmission of that virus.Dr. Daniel Griffin, an infectious disease physician at Columbia University in New York
We posit the next obvious conclusion: this principle could be used to triage and target who gets maBs in order to derive the maximum benefit in reduced hospitalizations and deaths. Of course vaccines are the first priority, and each vaccination reduces the number of at risk individuals. But if an at risk individual is infected before they receive a vaccination, there is now both an effective therapeutic and a tool to target its use. Surely, we must bias to action when lives are at stake?
As Dr. Alex Greninger, who led one of the studies, puts it:
“One of the things that’s been tough in this pandemic is everybody wants to do evidence-based medicine and wants to go at the appropriate speed,” Dr. Greninger said. “But we also should expect certain things to be true, like more virus is usually not good.”Dr. Alexander Greninger, a virologist at the University of Washington in Seattle