Characterization of Virologic Rebound Following Nirmatrelvir-Ritonavir Treatment for Coronavirus Disease 2019 (COVID-19)

We enrolled 7 individuals with recurrent symptoms or antigen test conversion following nirmatrelvir-ritonavir treatment. High viral loads (median 6.1 log(10) copies/mL) were detected after rebound for a median of 17 days after initial diagnosis. Three had culturable virus for up to 16 days after initial diagnosis. No known resistance-associated mutations were identified.

Automated summary

We enrolled 7 individuals who experienced recurrent symptoms or antigen test conversion after treatment with nirmatrelvir-ritonavir. High viral loads were detected after rebound, lasting a median of 17 days after initial diagnosis. Three individuals had culturable virus for up to 16 days after initial diagnosis. No known resistance-associated mutations were found.