Is Paxlovid treatment for Covid-19 effective? Study finds answers

A retrospective target trial emulation study has found that Nirmatrelvir-ritonavir treatment for COVID-19 showed limited effectiveness in preventing most post-COVID conditions (PCCs)but appeared to reduce the risk of combined thromboembolic events. The study focused on non hospitalized veterans in VHA care who tested positive for SARS-CoV-2 during January to July 2022. The cumulative incidence of 31 potential PCCs was measured 31 to 180 days after treatment or a matched index date.

The study included 9,593 participants treated with nirmatrelvir-ritonavir and their matched untreated comparators. The results indicated no significant differences in the incidence of most PCCs between the two groups. However, participants treated with nirmatrelvir-ritonavir showed a lower combined risk for venous thromboembolism and pulmonary embolism.

It's important to note that there may be inaccuracies in ascertaining PCCs using International Classification of Diseases codes, and the evaluation of multiple outcomes could lead to spurious associations by chance.

Out of the 31 potential PCCs examined, only the risk of combined thromboembolic events appeared to be reduced by nirmatrelvir-ritonavir treatment.

Reference: Effectiveness of Nirmatrelvir–Ritonavir Against the Development of Post–COVID-19 Conditions Among U.S. Veterans, FREE A Target Trial Emulation, George N. Ioannou et al, https://doi.org/10.7326/M23-1394