“Symptomatic relapse after nirmatrelvir-ritonavir therapy for early stage COVID-19 infection is associated with high viral load.”…
We enrolled seven individuals with recurrent symptoms following nirmatrelvir-ritonavir treatment. High viral loads were detected at enrollment and for a median of 17 days after initial diagnosis. Three of seven had culturable virus for up to 16 days after initial diagnosis.
Symptomatic relapse after nirmatrelvir-ritonavir therapy for early stage COVID-19 infection is associated with high viral load and, in a subset of individuals, culturable virus. We identified live virus at up to 11 days after completion of nirmatrelvir-ritonavir therapy (16 days from the pre-treatment PCR test).
By contrast, we recently reported that untreated outpatients infected with the Omicron variant SARS-CoV-2 shed viable virus for a median of 5 days after an initial positive test.