Alan Perelson, a LANL scientist and New Mexico Consortium affiliated scientist, recently published his paper titled, Success of prophylactic antiviral therapy for SARS-CoV-2: Predicted critical efficacies and impact of different drug-specific mechanisms of action in PLoS Computational Biology.
Currently, several repurposed drugs are being tested as a medication or as a preventative drug in order to prevent infection from SARS-CoV-2 (otherwise known as COVID-19)
This study evaluates the success of preventative drug treatment. The researchers looked at different drug types and their success of preventive treatment of viral infection by using a stochastic model of early phase infection.
The study finds that there is a critical effectiveness that a drug treatment must reach in order to block the establishment of the virus in the body. Treatment by a combination of drugs reduces the critical efficacy, most effectively by the combination of a drug blocking viral entry into cells and a drug increasing viral clearance. Even below the critical efficacy, the risk of infection can be reduced.
Drugs blocking viral entry into cells or enhancing viral clearance reduce the risk of infection more than drugs that reduce viral production in infected cells. The larger the initial inoculum of infectious virus, the less likely is prevention of an infection.
In their model, the researchers found that as long as the viral inoculum is smaller than 10 infectious virus particles, viral infection can be prevented almost certainly with drugs of 90% efficacy (or more).
Even when someone has already been infected with the virus, antivirals are still useful because they will delay the time it takes to get to detectable viral loads in the infected person. A delay of virus infection can possibly reduce transmission to others as well as the severity of symptoms.
The conclusion of this study is that, antiviral prevention drugs, even with reduced effectiveness, can be efficiently used to prevent a viral infection. Administering these antiviral drugs to people at high risk, such as health care workers, may be especially important during the COVID-19 pandemic.
See the entire paper at:
Czuppon P, De´barre F, Goncalves A, Tenaillon O, Perelson AS, Guedj J, et al. (2021) Success of prophylactic antiviral therapy for SARSCoV-2: Predicted critical efficacies and impact of different drug-specific mechanisms of action. PLoS Comput Biol 17(3): e1008752. https://doi.org/ 10.1371/journal.pcbi.1008752