tetano
Editor, Senior Moderator
Clin Infect Dis
. 2025 Oct 29:ciaf145.
doi: 10.1093/cid/ciaf145. Online ahead of print. Real-World Effectiveness of Nirmatrelvir-Ritonavir in Preventing Coronavirus Disease 2019-Associated Hospitalization: A Population-Based Cohort Study in the Province of Québec, Canada
Jean-Luc Kaboré[SUP] 1 [/SUP], Benoît Laffont[SUP] 1 [/SUP], Mamadou Diop[SUP] 1 [/SUP], Melanie R Tardif[SUP] 1 [/SUP], Alexis F Turgeon[SUP] 2 3 [/SUP], Jeannot Dumaresq[SUP] 4 5 [/SUP], Me-Linh Luong[SUP] 6 [/SUP], Michel Cauchon[SUP] 7 [/SUP], Hugo Chapdelaine[SUP] 8 9 [/SUP], David Claveau[SUP] 10 [/SUP], Marc Brosseau[SUP] 11 12 [/SUP], Elie Haddad[SUP] 13 [/SUP], Mike Benigeri[SUP] 1 [/SUP]
Affiliations
Background: The nirmatrelvir-ritonavir has shown to reduce coronavirus disease 2019 (COVID-19) hospitalization and death before the Omicron era, but updated real-world evidence studies are needed. The current study aimed to assess whether nirmatrelvir-ritonavir reduces the risk of COVID-19-associated hospitalization among high-risk outpatients.
Methods: This was a retrospective cohort study of severe acute respiratory syndrome coronavirus 2-infected outpatients between 15 March and 15 October 2022, using data from the Québec clinico-administrative databases. Propensity score matching was used to compare infected outpatients treated with nirmatrelvir-ritonavir with those not receiving nirmatrelvir-ritonavir. The relative risk (RR) of COVID-19-associated hospitalization occurring within 30 days following the index date was assessed using a Poisson regression.
Results: A total of 14 756 treated outpatients were matched to controls. Regardless of vaccination status, nirmatrelvir-ritonavir treatment was associated with a 74% reduced RR of hospitalization (RR, 0.26 [95% confidence interval [CI], .23-.29]; number needed to treat [NNT, 15). The effect was more pronounced in outpatients with an incomplete primary vaccination course (RR, 0.13 [95% CI, .08-.20]; NNT, 9). Benefit was also found in those with a complete primary vaccination course (RR, 0.28 [95% CI, .25-.32]; NNT, 17) regardless of age and the delay since the last vaccination. Subgroups analysis among high-risk outpatients with a primary vaccination course showed that nirmatrelvir-ritonavir treatment was associated with a significant decrease in the RR of hospitalization in severely immunocompromised outpatients (RR, 0.28 [95% CI, .21-.36]; NNT, 7), regardless of the delay since the last vaccination.
Conclusions: Nirmatrelvir-ritonavir reduces the risk of COVID-19-associated hospitalization among incompletely and completely vaccinated high-risk outpatients, as well as immunocompromised individuals, regardless of age and the delay since the last vaccination.
Keywords: COVID-19; SARS-Cov-2; effectiveness; nirmatrelvir; ritonavir.
. 2025 Oct 29:ciaf145.
doi: 10.1093/cid/ciaf145. Online ahead of print. Real-World Effectiveness of Nirmatrelvir-Ritonavir in Preventing Coronavirus Disease 2019-Associated Hospitalization: A Population-Based Cohort Study in the Province of Québec, Canada
Jean-Luc Kaboré[SUP] 1 [/SUP], Benoît Laffont[SUP] 1 [/SUP], Mamadou Diop[SUP] 1 [/SUP], Melanie R Tardif[SUP] 1 [/SUP], Alexis F Turgeon[SUP] 2 3 [/SUP], Jeannot Dumaresq[SUP] 4 5 [/SUP], Me-Linh Luong[SUP] 6 [/SUP], Michel Cauchon[SUP] 7 [/SUP], Hugo Chapdelaine[SUP] 8 9 [/SUP], David Claveau[SUP] 10 [/SUP], Marc Brosseau[SUP] 11 12 [/SUP], Elie Haddad[SUP] 13 [/SUP], Mike Benigeri[SUP] 1 [/SUP]
Affiliations
- PMID: 41160182
- DOI: 10.1093/cid/ciaf145
Background: The nirmatrelvir-ritonavir has shown to reduce coronavirus disease 2019 (COVID-19) hospitalization and death before the Omicron era, but updated real-world evidence studies are needed. The current study aimed to assess whether nirmatrelvir-ritonavir reduces the risk of COVID-19-associated hospitalization among high-risk outpatients.
Methods: This was a retrospective cohort study of severe acute respiratory syndrome coronavirus 2-infected outpatients between 15 March and 15 October 2022, using data from the Québec clinico-administrative databases. Propensity score matching was used to compare infected outpatients treated with nirmatrelvir-ritonavir with those not receiving nirmatrelvir-ritonavir. The relative risk (RR) of COVID-19-associated hospitalization occurring within 30 days following the index date was assessed using a Poisson regression.
Results: A total of 14 756 treated outpatients were matched to controls. Regardless of vaccination status, nirmatrelvir-ritonavir treatment was associated with a 74% reduced RR of hospitalization (RR, 0.26 [95% confidence interval [CI], .23-.29]; number needed to treat [NNT, 15). The effect was more pronounced in outpatients with an incomplete primary vaccination course (RR, 0.13 [95% CI, .08-.20]; NNT, 9). Benefit was also found in those with a complete primary vaccination course (RR, 0.28 [95% CI, .25-.32]; NNT, 17) regardless of age and the delay since the last vaccination. Subgroups analysis among high-risk outpatients with a primary vaccination course showed that nirmatrelvir-ritonavir treatment was associated with a significant decrease in the RR of hospitalization in severely immunocompromised outpatients (RR, 0.28 [95% CI, .21-.36]; NNT, 7), regardless of the delay since the last vaccination.
Conclusions: Nirmatrelvir-ritonavir reduces the risk of COVID-19-associated hospitalization among incompletely and completely vaccinated high-risk outpatients, as well as immunocompromised individuals, regardless of age and the delay since the last vaccination.
Keywords: COVID-19; SARS-Cov-2; effectiveness; nirmatrelvir; ritonavir.