SARS-CoV-2 – Nirmatrelvir: A Key Component Of Paxlovid Blunts Development Of Antiviral Adaptive Immune Responses

A new study by Italian researchers has found that Nirmatrelvir which is a key component of the drug Paxlovid blunts the development of antiviral adaptive immune responses in mice infected with SARS-CoV-2.

The study findings were published on a preprint server and are currently being peer reviewed.
https://www.biorxiv.org/content/10.1101/2022.11.22.517465v1
 

Alongside vaccines, antiviral drugs are becoming an integral part of our response to the SARS-CoV-2 pandemic. Nirmatrelvir – an orally available inhibitor of the 3- chymotrypsin-like cysteine protease – has been shown to reduce the risk of progression to severe COVID-19.

However, the impact of nirmatrelvir treatment on the development of SARS-CoV-2-specific adaptive immune responses is unknown. Here, by using a mouse model of SARS-CoV-2 infection, we show that nirmatrelvir administration early after infection blunts the development of SARS-CoV-2-specific antibody and T cell responses.

Accordingly, upon secondary challenge, nirmatrelvir-treated mice recruited significantly fewer memory T and B cells to the infected lungs and to mediastinal lymph nodes, respectively.

Together, the data highlight a potential negative impact of nirmatrelvir treatment with important implications for clinical management and might help explain the virological and/or symptomatic relapse after treatment completion reported in some individuals.