What is Paxlovid and how does it work? Paxlovid is a combination treatment that uses two different antivirals: nirmatrelvir and ritonavir.
Nirmatrelvir works to prevent the virus replicating. It does this by stopping a viral enzyme called a protease. SARS-CoV-2, like many viruses, rely on proteases to “activate" them.
Without the protease, the virus replication cycle cannot be completed and the virus can not become active. So rather than “killing" the virus, it stops new “active" virus particles from being made.
Ritonavir is a “boosting agent" which prevents the metabolism of nirmatrelvir, meaning it stays in your system for longer. Ritonavir has been used in low doses to boost the effectiveness of other protease antivirals in infections such as HIV.