The antiviral, Remdesivir, is the only drug to date that the United States Food & Drug Administration has approved for the treatment of Covid-19. But three monoclonal antibody treatments have been issued emergency use authorization.
Antivirals work not to kill but to limit production of the virus so that duration of the illness is shortened and risk of complications is reduced. Monoclonal antibody treatments, on the other hand, provide our bodies with lab-created proteins that act like antibodies to help our immune system fight the virus.
These treatments, however, can only be administered intravenously or by injection and thus can be done only in a hospital setting. They are also expensive, limited in supply and have a narrow window of time to be effective.
Remdesivir continues to receive mixed evidence of effectiveness. Monoclonal antibody treatments, on the other hand, show limited efficacy against some variants.
But then comes Molnupiravir, the investigational antiviral drug by Merck. Now in Phase 3 trials, it’s been shown to remarkably reduce hospitalization or death by as much as 50 percent in patients with mild to moderate Covid-19.
As a virus replicates, it makes copying errors or genetic mutations. But it can only make so many errors or mutations. When its error threshold is breached, defective copies result—making the virus lose its viability.
This is lethal mutagenesis or virus extinction by error catastrophe.
Molnupiravir acts to artificially push mutation rates so high as to cause the virus to make so many errors, impairing its fitness, inhibiting its replication and rendering it extinct in its host.
Trials of Molnupiravir show it to be safe and well tolerated with good efficacy across many variants. But the best thing about it—is that it comes in capsule form.
This means it will be easier to transport, store and administer. It will also be faster to produce, less expensive to procure and will thus be more widely available.
So, has the game changer arrived? Perhaps. But it is still not a panacea. It must be given early. It doesn’t benefit those who are severely ill. And it only works 50 percent of the time. So, we still can’t risk being sick.
Prevention is still better than cure. So, no, we don’t ditch the vaccines.
Treatments benefit only the person being treated. Vaccines benefit everyone. Not all of us will get this drug in time while the vaccines are available now. Treatments are costly. Vaccines are free—at least for now.
So, however Mulnopiravir plays out eventually, the end of this pandemic will likely not come from one game changer but from the synergistic effects of many: widespread vaccination, improved testing, effective treatments and compliance of safety protocols.