Nirmatrelvir-Ritonavir Speeds COVID-19 Recovery but Fails to Reduce Hospitalizations in Vaccinated High-Risk Adults

Since its approval in 2021, nirmatrelvir-ritonavir (Paxlovid; Pfizer) has been a cornerstone of outpatient COVID-19 treatment. The drug earned authorization on the strength of the phase 2/3 EPIC-SR trial (NCT05011513), which demonstrated an 88% reduction in hospitalization or death among unvaccinated, high-risk adults. However, that pivotal trial was conducted at a time when population-level immunity was minimal and pre-Omicron variants were circulating—conditions vastly different from today's landscape.^1,2

As vaccination rates climbed globally, clinicians and health policymakers have been left questioning whether nirmatrelvir-ritonavir’s original efficacy data still apply to the patients most commonly seen in practice.^1,2

A pair of large, open-label, adaptive platform trials, the UK PANORAMIC trial and the Canadian CanTreatCOVID trial, sought to answer that question. The results were published in the New England Journal of Medicine.³

Study Design

The PANORAMIC study, led by researchers at the University of Oxford, enrolled 3516 participants across England, Wales, Scotland, and Northern Ireland between April 2022 and March 2024. The CanTreatCOVID trial, led by Upstream Lab at Unity Health Toronto, enrolled 716 participants between January 2023 and September 2024. Both trials recruited adults 50 years or older, or adults 18 years or older with comorbidities such as diabetes or asthma.^3,4

All participants had tested positive for SARS-CoV-2, had been symptomatic for no more than 5 days, and more than 98% were vaccinated against COVID-19. Participants were randomly assigned to receive either usual care plus nirmatrelvir 300 mg/ritonavir 100 mg twice daily for 5 days or usual care alone, with a 28-day follow-up.^3,4

Key Findings

The primary outcome, which was hospitalization or all-cause death within 28 days, showed no statistically significant difference between the nirmatrelvir-ritonavir and usual-care groups in either trial. In PANORAMIC, 0.8% of Paxlovid recipients were hospitalized or died compared with 0.7% in the usual care arm. In CanTreatCOVID, rates were 0.6% vs 1.2%, respectively; however, the study authors noted that these results were not statistically significant. No deaths occurred in either trial during the nirmatrelvir-ritonavir recruitment period.^3,4

Despite the lack of effect on severe outcomes, nirmatrelvir-ritonavir did meaningfully shorten the time to recovery. In PANORAMIC, median recovery was 14 days with Paxlovid vs 21 days with usual care. CanTreatCOVID reported a similar trend, with recovery at 6 days vs 9 days in the usual-care group. Additionally, nirmatrelvir-ritonavir significantly reduced SARS-CoV-2 viral load by day 5, a finding with potential implications for limiting transmission.^3,4

The safety profile was consistent with prior data. In PANORAMIC, approximately 90% of nirmatrelvir-ritonavir recipients reported at least one adverse event (AE), most commonly dysgeusia and gastrointestinal symptoms. Approximately 8% of participants discontinued treatment due to AEs, although serious AEs were rare in both groups.^3,4

Clinical and Policy Implications

These findings have significant implications for how pharmacists and prescribers approach nirmatrelvir-ritonavir in the current era. In an accompanying editorial published in the New England Journal of Medicine, former NIAID director Anthony Fauci, MD; and H. Clifford Lane, MD, cautioned against concluding that nirmatrelvir-ritonavir has no remaining clinical value. They noted that faster recovery and reduced viral load represent meaningful end points and recommended that clinicians continue to consider antivirals on a case-by-case basis—particularly for older adults, immunocompromised individuals, and those for whom rapid recovery is a priority.⁵

These results come after the United Kingdom’s National Institute for Health and Care Excellence moved in May 2025 to restrict routine NHS Paxlovid prescribing to a narrower “highest-risk” cohort, citing cost-effectiveness concerns. That designation encompasses patients such as solid organ transplant recipients and those with severe liver disease—groups in whom the absolute risk of severe COVID-19 remains elevated despite vaccination.^3,4

Earlier research helped frame this evolving picture. A 2024 Pfizer-sponsored trial in vaccinated outpatients found only a marginal 1-day reduction in the time to symptom relief with Paxlovid vs placebo and no significant difference in hospitalizations. Alongside the PANORAMIC and CanTreatCOVID data, these studies collectively indicate that the dramatic benefit seen in the EPIC-HR trial—conducted in a population without vaccine-derived or infection-acquired immunity—is unlikely to translate to today's broadly immunized patient population.²

Takeaways for Pharmacy Practice

Pharmacists play a central role in nirmatrelvir-ritonavir prescribing decisions, particularly given the drug's well-known drug–drug interaction profile with ritonavir as a pharmacokinetic booster. Although the new evidence does not support Paxlovid as a universal standard of care in vaccinated outpatients, it remains an important option for appropriately selected patients. Clinicians and pharmacists should continue individualized risk assessment, focusing nirmatrelvir-ritonavir use on those at the highest risk for severe disease—including those who are immunocompromised, older individuals with multiple comorbidities, and others who may derive meaningful benefit from faster recovery or reduced viral burden.

REFERENCES

1. Evaluation of protease inhibition for COVID-19 in standard-risk patients (EPIC-SR). ClinicalTrials.gov. Updated August 14, 2023. Accessed April 30, 2026. https://clinicaltrials.gov/study/NCT05011513

2. Hammond J, Fountaine RJ, Yunis C, et al. Nirmatrelvir for vaccinated or unvaccinated adult outpatients with Covid-19. N Engl J Med. 2024;390(13):1186-1195. doi:10.1056/NEJMoa2309003

3. Butler CC, Pinto AD, Harris V, et al; PANORAMIC Trial and CanTreatCOVID Trial Collaborative Groups. Oral nirmatrelvir–ritonavir for Covid-19 in higher-risk outpatients. N Engl J Med. 2026;394(16):1583-1594. doi:10.1056/NEJMoa2502457

4. COVID antiviral speeds recovery but doesn't reduce hospitalization in vaccinated patients, trials find. News release. University of Oxford. April 22, 2026. Accessed April 30, 2026. https://www.eurekalert.org/news-releases/1125116

5. Gandhi RT, Hirsch M. Treating acute Covid-19 — final chapters still unwritten. N Engl J Med. 2024;390(13):1234-1236. doi:10.1056/NEJMe2402224