Following his positive Covid-19 test, US President Donald Trump was admitted to Walter Reed hospital and given a cocktail of drugs – among them the antiviral Remdesivir.
After receiving a series of treatments from doctors, including a course of the antiviral, Trump was discharged from hospital three-days after admission, reporting he was symptom free.
At present, the eventual outcome for the President is uncertain, but his case does focus attention on the possible use of these drugs in the treatment of Covid-19.
Antivirals vs Vaccines
Unlike vaccines which prime the immune system to respond rapidly to subsequent exposure of a specific virus, antiviral drugs act directly on the virus to prevent replication inside the host’s cells or to block entry of the virus to the cell.
While waiting for the development of an appropriate vaccine, clinical trials are underway using antiviral drugs already in circulation for the treatment of other viral illnesses, testing their effectiveness on Covid-19 patients.
In this way, drugs such as Remdesivir could be repurposed and put into general circulation for use in severe cases of Covid-19.
Remdesivir is an antiviral drug which reduces the viral load by inhibiting the replication of the virus.
Originally developed as a treatment for Hepatitis C and used in combating Ebola, the drug has been shown to be effective against several viruses, including some coronaviruses.
In May 2020, Remdesivir became the first therapy drug authorised for emergency use in severe cases of Covid-19 in the US and subsequently the NHS.
A recent clinical trial of more than 1000 people found the drug cuts the duration of symptoms caused by Covid-19 from 15 days to 11.
Additionally, trials showed administration of Remdesivir shortly after infection could reduce the number of viral particles an infected individual sheds, thereby reducing infectiveness and transmission.
The importance of antivirals
The ongoing Covid-19 epidemic is threatening millions of lives globally, along with risking overwhelming the health systems of many countries and causing dire economic consequences.
Across the world, more than 100 Covid-19 vaccines are currently being developed, but with the need for trials to review safety and effectiveness, successful vaccines can take ten or more years to become available.
Additionally, the immunity provided by a vaccine may be short-lived and there is risk that Covid-19 may not respond to vaccination, meaning it’s important we look to other remediation strategies.
Repurposing antiviral drugs is a viable remediation strategy, and because they are already in circulation, there is little or no need for extensive safety trials.
Alternative Covid-19 drug treatments
In addition to Remdesivir, Trump was administered a novel cocktail of monoclonal antibodies, which bind to the virus and prevent it from entering the host’s cells – again, the effectiveness of this treatment awaits clarification.
Researchers at the University of Bristol are studying the 3D structure of Covid-19, in the possibility of developing small chemical drugs that would interact with the virus proteins and stop infection.
While none of these approaches have been found to be a cure for Covid-19, reducing recovery time in patients is an important step in the fight against the virus.