Hospitalization and Emergency Department Encounters for COVID-19 After Paxlovid Treatment — California, December 2021–May 2022

Malden, Deborah E; Hong, Vennis; Lewin, Bruno; Ackerson, Bradley; Lipsitch, Marc; Lewnard, Joseph A; Tartof, Sara Y

doi:10.15585/mmwr.mm7125e2

Cited by 63 publications

(59 citation statements)

References 7 publications

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“…Our findings support the study by Malden et al who found that ED visits or hospitalizations occurred with less than one percent frequency in the 5-15 days after NMV-r treatment. 6 Our findings also support observed NMV-r neutralization of Omicron variants in vitro and those of recently published data in high-risk outpatients and lower severity inpatients. 7,8,20 Notably, the study by Arbel et al found that high-risk outpatients in Israel aged 40-64 and infected with COVID-19 did not appear to derive benefit from nirmaltrelvir with respect to reduced hospitalization, yet among patients 65 or older, the adjusted HR of 0.21 suggested striking benefit from nirmaltrelvir.…”

Section: Discussionsupporting

confidence: 92%

Real-world Use of Nirmatrelvir-Ritonavir in COVID-19 Outpatients During the Emergence of Omicron Variants BA.2/BA2.12.1

Aggarwal

Molina

Beaty

et al. 2022

Preprint

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Background: Ritonavir-boosted Nirmatrelvir (NMV-r), a protease inhibitor with in vitro activity against SARS-CoV-2, has been shown to reduce risk of progression to severe COVID-19 among high-risk individuals during the Delta-variant phase. We sought to determine the effectiveness of NMV-r against Omicron lineage variants BA.2/BA2.12.1, and assess for evidence of a clinical rebound effect.Methods: We conducted a retrospective observational cohort study of non-hospitalized adult patients with SARS-CoV-2 infection from March 26 th , 2022 to June 23 rd , 2022, using records from a statewide health system linked to vaccine and mortality data. Propensity score matching was performed on NMV-r treated outpatients with outpatients not treated with antiviral therapy. The primary outcome was 28day all-cause hospitalization; secondary outcomes were COVID-19-related hospitalization, 28-day allcause mortality, and 28-day ED visits. Logistic regression was used to determine NMV-r treatment effectiveness; subgroup analyses were performed to assess for heterogeneity in treatment effect.Results: Of 14,953 SARS-CoV-2 infected outpatients, 3,614 NMV-r treated patients were matched to 4,835 untreated outpatients. NMV-r was associated with significantly lower odds of 28-day all-cause hospitalization as compared to no antiviral treatment [31 (0.9%) vs. 64 (1.3%), adjusted odds ratio (aOR): 0.48 (95% CI 0.31-0.75)]. NMV-r was also associated with lower odds of COVID-19 related hospitalization [aOR (95% CI): 0.42 (0.25-0.68)] and 28-day all-cause mortality [aOR (95% CI): 0.05 (0.00-0.38)]. Using ED visits within 28 days as a surrogate for rebound symptoms, we observed no clinically evident rebound effect with NMV-r treatment [140 (3.9%) vs 205 (4.2%), aOR: 0.81 (95% CI 0.65-1.02), p = 0.075].Conclusion: Real-world evidence during an Omicron BA.2/BA2.12.1 predominant period demonstrated an association of NMV-r treatment with reduced 28-day hospitalization and all-cause mortality, and without an increase in rebound symptoms as assessed by ED visits within 28 days after treatment.

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Section: Discussionsupporting

confidence: 92%

Real-world Use of Nirmatrelvir-Ritonavir in COVID-19 Outpatients During the Emergence of Omicron Variants BA.2/BA2.12.1

Aggarwal

Molina

Beaty

et al. 2022

Preprint

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“…Fortunately, effective vaccines and first-generation therapies have become quickly available and are being distributed on an emergency basis. However, given the emergence of more contagious and potentially pathogenic variants, and ongoing issues of emerging resistance, the continued search for new therapeutics remains a priority (Firestone, 2021;Malden, 2022;Mwenda, 2021). Therapeutics discovery efforts for SARS-CoV-2 were launched by a series of repurposing screens of varying sizes.…”

Section: Introductionmentioning

confidence: 99%

Identification of potent inhibitors of SARS-CoV-2 infection by combined pharmacological evaluation and cellular network prioritization

et al. 2022

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“…29, 31 An additional descriptive study found that <1% of US patients who received nirmatrelvir/ritonavir were hospitalized or visited the emergency department in the 5−15 days following treatment. 32 By contrast, a Hong Kong study identified 4.4% and 6.2% hospitalization rates among nirmatrelvir/ritonavir and non-nirmatrelvir/ritonavir recipients, respectively, within 28 days of diagnosis. 33 Our study found higher hospitalization rates than in the Massachusetts/New Hampshire and Israeli studies (nirmatrelvir/ritonavir group, 1.2%; non-nirmatrelvir/ritonavir group, 6.9%) and slightly lower rates than online-published results from a US database study (nirmatrelvir/ritonavir group, 1.9%; non-nirmatrelvir/ritonavir group, 9.7% 34 ).…”

Section: Discussionmentioning

confidence: 92%

“…We used hospitalization as a proxy of COVID-19−attributed hospitalization; however, because the data do not capture causes of hospitalization, inclusion of admission and encounters for conditions other than COVID-19 could result in outcome misclassification. The sensitivity analysis used a narrower risk window (ie, 15 days), as adopted in other real-world studies, 29, 32 to help reduce potential effects of misclassification due to a longer risk window. However, this would not affect incidental hospitalization on the COVID-19 diagnosis date.…”

Section: Discussionmentioning

confidence: 99%

Real-World Effectiveness of Nirmatrelvir/Ritonavir in Preventing Hospitalization Among Patients With COVID-19 at High Risk for Severe Disease in the United States: A Nationwide Population-Based Cohort Study

Zhou

Kelly

Liang

et al. 2022

Preprint

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Objectives: The aim of this analysis was to describe nirmatrelvir/ritonavir real-world effectiveness in preventing hospitalization among high-risk US COVID-19 patients during SARS-CoV-2 Omicron predominance. Design: An ongoing population-based cohort study with retrospective and prospective collection of electronic healthcare data in the United States. Methods: Data for this analysis were collected from the US Optum de-identified COVID-19 Electronic Health Record (EHR) dataset during December 22, 2021 to June 8, 2022. Key eligibility criteria for inclusion in the database analysis were at least 12-years-old; positive SARS-CoV-2 test, COVID-19 diagnosis, or nirmatrelvir/ritonavir prescription; and high risk of severe COVID-19 based on demographic/clinical characteristics. Potential confounders between groups were balanced using propensity score matching (PSM). Immortal time bias was addressed. Outcome measures: Hospitalization rates within 30 (primary analysis) or 15 (sensitivity analysis) days from COVID-19 diagnosis overall and within subgroups were evaluated. Results: Before PSM, the nirmatrelvir/ritonavir group (n=2811) was less racially diverse, older, and had higher COVID-19 vaccination rates and a greater number of comorbidities than the non-nirmatrelvir/ritonavir group (n=194,542). Baseline characteristics were well balanced across groups (n=2808 and n=10,849, respectively) after PSM. Incidence of hospitalization (95% CI) within 30 days was 1.21% (0.84%, 1.69%) for the nirmatrelvir/ritonavir group and 6.94% (6.03%, 7.94%) for the non-nirmatrelvir/ritonavir group, with a hazard ratio (95% CI) of 0.16 (0.11, 0.22; 84% relative risk reduction). Incidence within 15 days was 0.78% (0.49%, 1.18%) for the nirmatrelvir/ritonavir group and 6.54% (5.65%, 7.52%) for the non-nirmatrelvir/ritonavir group; hazard ratio 0.11 (0.07, 0.17; 89% relative risk reduction). Nirmatrelvir/ritonavir was effective in African American patients (hazard ratio, 0.35 [0.15, 0.83]; 65% relative risk reduction). Relative risk reductions were comparable with overall results across ages and among vaccinated patients. Conclusions: Real-world nirmatrelvir/ritonavir effectiveness against hospitalization during the Omicron era supports EPIC-HR efficacy among high-risk patients. Future research should confirm these early real-world results and address limitations.

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Hospitalization and Emergency Department Encounters for COVID-19 After Paxlovid Treatment — California, December 2021–May 2022

Cited by 63 publications

References 7 publications

Real-world Use of Nirmatrelvir-Ritonavir in COVID-19 Outpatients During the Emergence of Omicron Variants BA.2/BA2.12.1

Real-world Use of Nirmatrelvir-Ritonavir in COVID-19 Outpatients During the Emergence of Omicron Variants BA.2/BA2.12.1

Identification of potent inhibitors of SARS-CoV-2 infection by combined pharmacological evaluation and cellular network prioritization

Real-World Effectiveness of Nirmatrelvir/Ritonavir in Preventing Hospitalization Among Patients With COVID-19 at High Risk for Severe Disease in the United States: A Nationwide Population-Based Cohort Study

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