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The Potential of Antivirals

Seema Patel
Hospital Business Medical Lead, Pfizer UK

22nd February 2021

Could the secret to a potential COVID-19 treatment lie in a protease inhibitor?


Alongside global efforts to develop and produce multiple COVID-19 vaccines, scientists and researchers around the world are also investigating the potential of antiviral treatments to attempt to lower the impact of the virus on patients' lives. These potential treatments, which work by interrupting the virus’ ability to multiply, could offer an opportunity to help treat COVID-19 patients.

All viruses, including SARS-CoV-2, the virus that causes COVID-19, have the same goal: to invade our cells, use our cells’ internal machinery to make copies of itself, and then release the newly made virus to infect more cells. This is known as the viral life cycle. When COVID-19 emerged, we revisited our current and retired library of compounds with the hope of identifying potential candidates that could be used to treat COVID-19 and/or its symptoms by slowing or interrupting the life cycle of the SARS-CoV virus.

Through this research, one of the compounds identified during our previous SARS (severe acute respiratory syndrome) protease inhibitor pre-clinical programme showed promising antiviral activity against coronaviruses, which are responsible for causing both SARS in 2003 and COVID-19 today. Known as a protease inhibitor, this potential antiviral treatment works by blocking a critical enzyme (a protease) that the virus needs to replicate. Clinical trials are underway and if successful, this could help to potentially reduce the symptoms associated with COVID-19 and lessen the risk of significant health complications for patients.

Take a look behind the science to find out more:



The collaborative effort needed to develop potential COVID-19 treatments is only possible with the dedicated work of our research partners and those individuals who have volunteered to take part in clinical trials around the world. We are continually grateful to each of the clinical trial investigators and their study teams who are partnering with us in this effort, and to all the participants continuing to volunteer to help make a difference for society.

By focusing on breakthrough science, leaning on the dedication and expertise of our scientific colleagues and partners, and harnessing the courage of clinical trial volunteers, we believe #ScienceWillWin in the fight against COVID-19.



  1. Pfizer Inc. Data on file.


How do antivirals contribute to the treatment of COVID-19?

Certain antivirals help to slow or stop a virus from replicating, therefore could be used to help reduce the symptoms associated with COVID-19 and the risk of significant health complications. The Pfizer investigational antiviral compound is a protease inhibitor, which interferes with an essential step needed for the coronavirus to make copies of itself. This compound is currently being investigated for potential treatment of COVID-19.

What kind of antiviral is Pfizer investigating?

Pfizer is currently investigating an antiviral candidate compound called a protease inhibitor. This compound could potentially inhibit the protease enzyme that coronaviruses need to replicate, therefore helping to reduce the symptoms associated with COVID-19 and the risk of other health complications.

PP-PFE-GBR-3447 / Feb 2021