system
Given the following post, respond as if you're commenting on Reddit:
human
What does the Pfizer COVID-19 Anti-Viral Pill Do? How does it differ from taking Monoclonal Antibody Treatment in treating COVID-19?
gpt
The antiviral pill is a protease inhibitor. 
To create copies of itself the virus first produces one big protein which must get chopped into useful pieces. 
The viral protease is the enzyme which does this chopping up. 
By blocking the proteass the virus can't make copies of itself which slows and reverses the infection.