Paxlovid (nirmatrelvir/ritonavir) / Pfizer, China Meheco Group - LARVOL DELTA

Anti-influenza and anti-COVID-19 drugs promote bacterial antibiotic cross-resistance through drug-specific adaptive pathways. (PubMed, Environ Pollut) - "Here, we investigated the antibacterial off-target effects of four clinically used anti-IFV/COV drugs-baloxavir acid (BXA), favipiravir (FAV), nirmatrelvir/ritonavir (NMV/r), and oseltamivir phosphate (OSV)-and their potential to influence bacterial stress responses and antibiotic cross-resistance in Escherichia coli, Bacillus subtilis, and Pseudomonas aeruginosa PAO1. Comparative transcriptomic analysis further revealed that cross-resistance did not arise from a universal resistance pathway, but from drug-specific adaptive remodeling, including transporter and metabolic responses under BXA, sporulation/biofilm-associated developmental responses under NMV/r, and a more limited response to OSV. Together, this study provides initial systematic evidence that clinically used anti-IFV/COV drugs can directly perturb bacterial physiology and promote antibiotic cross-resistance under both elevated and environmentally relevant exposure scenarios, identifying antiviral..."

Journal • Infectious Disease • Influenza • Novel Coronavirus Disease • Respiratory Diseases

Diagnostic Pitfall: Prolonged COVID-19 Presenting as Organising Pneumonia in a Rituximab-Treated Patient with Rheumatoid Arthritis. (PubMed, Mediterr J Rheumatol) - "Rituximab (RTX)-induced B-cell depletion is associated with prolonged SARS-CoV-2 infection. Retreatment with a second 5-day course of nirmatrelvir/ritonavir led to rapid clinical improvement and complete radiological resolution. Persistent SARS-CoV-2 infection should be considered in RTX-treated patients with non-resolving pulmonary infiltrates, particularly when corticosteroid therapy is ineffective."

Journal • Gastrointestinal Disorder • Immunology • Infectious Disease • Inflammation • Inflammatory Arthritis • Novel Coronavirus Disease • Pneumonia • Respiratory Diseases • Rheumatoid Arthritis • Rheumatology

Prognostic factors in the selection of antivirals for COVID-19 in high-risk outpatients: A retrospective cohort study. (PubMed, Ther Adv Infect Dis) - "Drug-drug interaction concerns, particularly between ritonavir and statins, drove physicians toward molnupiravir even when nirmatrelvir/ritonavir would otherwise have been the preferred agent. Systematic incorporation of pharmacist-conducted medication assessment before antiviral prescribing represents a practicable strategy for reducing avoidable drug substitution in high-risk patients."

Biomarker • Journal • Retrospective data • Infectious Disease • Novel Coronavirus Disease

Deep learning survival analysis with time-varying covariates: extending PyCox to assess COVID-19 antiviral treatments and long-COVID associations. (PubMed, JAMIA Open) - "We compared traditional Cox regression, original PyCox, and modified PyCox in estimating associations between early antiviral treatment (nirmatrelvir or molnupiravir) and long-COVID. Treatment-contrast magnitude and covariate importance varied by models, suggesting temporal covariate structure and modeling approach jointly influence treatment-effect estimates. Extending PyCox to accommodate time-varying covariates improves computational efficiency while maintaining estimation accuracy comparable to standard time-varying methods."

Journal • Infectious Disease • Novel Coronavirus Disease

Potent halt of SARS-CoV-2 replication using clitocine-induced emergent-viral-RNA editing and disruption. (PubMed, RSC Adv) - "The in vitro anti-RdRp, anti-ExoN, and anti-SARS-CoV-2 assays demonstrated the potent inhibitory activities of the CLT molecule and its expected major active metabolite, CLT triphosphate (CLT-TP), on coronaviral replication, with very interesting 50% inhibitory concentration (IC50) values against the nirmatrelvir-resistant SARS-CoV-2 variant "NRSV" (0.19, 0.20, and 0.38 µM for CLT and 0.15, 0.18, and 0.34 µM for CLT-TP, respectively), using the structurally similar and approved anti-SARS-CoV-2 medication molnupiravir (MNP) and its known active triphosphate metabolite, β-D-N 4-hydroxycytidine 5'-triphosphate (NHC-TP), respectively, as reference drugs. Through this new study, we also succeeded in uncovering and explaining the molecular-level mechanistic hallmarks of CLT/CLT-TP with respect to disrupting and impairing the coronaviral replication, as well as militating COVID-19 in a comprehensive way. In conclusion, the presented results need to be..."

Journal • Infectious Disease • Novel Coronavirus Disease • Oncology • Respiratory Diseases

Mutation-Aware Machine Learning Framework for Predicting Binding Affinity of Nirmatrelvir Analogs Targeting Coronavirus Main Proteases. (PubMed, Molecules) - "The ensemble model accurately predicted the binding affinities of Nirmatrelvir and its four analogues (E1-E4), reproducing the experimental pIC50 trend and correctly identifying the most potent inhibitors. The ensemble model also showed consistent performance across all MERS-CoV Mpro variants, S147Y, S142G, L144A, S142G/S147Y, and S142G/L144A/S147Y, demonstrating its potential for rapidly discovering mutation-resistant antiviral drugs."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Real-world Effectiveness of Nirmatrelvir-Ritonavir in Reducing Severe COVID-19 Outcomes by Age Groups in Canada (IDWeek 2026) - No abstract available

Clinical • Real-world • Real-world effectiveness • Real-world evidence • Infectious Disease • Novel Coronavirus Disease

Pregnancy and Infant Outcomes Following Exposure to PAXLOVID: Interim Results from A Post-Authorization Safety Study (IDWeek 2026) - No abstract available

Clinical • Infectious Disease • Novel Coronavirus Disease

Effectiveness of Nirmatrelvir/ritonavir in preventing severe COVID-19 outcomes by predominant variant period: National multi-year data from Greece (IDWeek 2026) - No abstract available

Infectious Disease • Novel Coronavirus Disease

Effectiveness and Safety of Nirmatrelvir/Ritonavir in Solid Organ Transplant Recipients with COVID-19: A Systematic Review and Meta-Analysis (IDWeek 2026) - No abstract available

Retrospective data • Review • Infectious Disease • Novel Coronavirus Disease

Oral MDL-001 a Universal Direct Acting Antiviral for Influenza Like Illness(ILI): In Vivo Equivalence or Superiority to Oseltamivir, Nirmatrelvir and Remdesivir, In Vitro Superiority to Ribavirin (IDWeek 2026) - No abstract available

Head-to-Head • Preclinical • Infectious Disease • Influenza

COVID-19, an Evolving Disease � The ACE-2 Narrative (IDWeek 2026) - "Supported by Paxlovid"

Infectious Disease • Novel Coronavirus Disease

The Evolving COVID-19 Antiviral Landscape: Insights from Pfizer's Development Pipeline (IDWeek 2026) - "Supported by Paxlovid"

Infectious Disease • Novel Coronavirus Disease

Improved Virologic Control in Severely Immunocompromised (SIC) Adults with COVID-19 Receiving Extended Duration Paxlovid Therapy (IDWeek 2026) - No abstract available

Clinical • Infectious Disease • Novel Coronavirus Disease

Exploring the Pyrimidine Scaffold for the Development of SARS-CoV-2 Mpro Inhibitors. (PubMed, ACS Infect Dis) - "Currently, only one protease antiviral agent (nirmatrelvir) has received emergency approval for COVID-19 treatment, the disease caused by SARS-CoV-2 infection...A series of derivatives were evaluated in both biochemical and cell-based assays to assess their antiviral efficacy, with some of them being able to inhibit the SARS-CoV-2 Mpro activity and to suppress viral replication. Docking studies were confirmed by site-directed mutagenesis, and the mechanism of action of the most promising compound was elucidated."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Model-Based Tacrolimus Dosing Using the Population Pharmacokinetic Analysis Under the Nirmatrelvir/Ritonavir Therapy. (PubMed, CPT Pharmacometrics Syst Pharmacol) - "The optimal dosing strategy based on the simulation was to withhold tacrolimus during nirmatrelvir/ritonavir therapy and to restart tacrolimus at 10% of the baseline dose on day 1, followed by 20% on day 3% and 50% on day 6, and increased to 100% on day 9 after discontinuation of nirmatrelvir/ritonavir, respectively. The proposed strategy will contribute to a safe and effective tacrolimus therapy when used in combination with nirmatrelvir/ritonavir."

Journal • PK/PD data • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

From Inhibitor to Reporter: Nirmatrelvir-Derived Fluorogenic Substrates for the SARS-CoV-2 Main Protease. (PubMed, ACS Chem Biol) - "Comparative X-ray crystallographic analyses revealed high similarity in the molecular interactions of the C145A mutant Mpro with nirmatrelvir and with a peptide whose sequence was derived from a natural Mpro substrate. The tetrapeptidic AMC derivative 6 will serve as a valuable biochemical tool contributing to the optimization of SARS-CoV-2 Mpro-directed drug research."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

A Case of Propafenone and Warfarin Toxicity Precipitated by Nirmatrelvir/Ritonavir for COVID-19 (AHA 2026) - "Abstract is embargoed at this time."

Clinical • Infectious Disease • Novel Coronavirus Disease

Dimerization and Ligand Binding Rewire Allosteric Networks in SARS-CoV-2 Main Protease. (PubMed, Biophys J) - "For each of these states, we simulated MPro in the apo state, as well as bound to a natural peptide substrate (nsp 15/16), the covalent inhibitor nirmatrelvir (Paxlovid) and the noncovalent inhibitor ensitrelvir (Xocova). Together, these findings define how correlated motion networks couple active-site dynamics to dimerization and ligand binding, providing molecular insight into the principles governing allosteric regulation in MPro. This framework highlights potential avenues for developing antivirals that target not only the catalytic site but also the communication pathways sustaining dimer stability and enzymatic function."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Discovery of piperazine-based multi-site occupying coronavirus Mpro inhibitors with potent and broad-spectrum antiviral activity. (PubMed, Eur J Med Chem) - "Moreover, both compounds exhibited broad-spectrum antiviral activity against other human coronaviruses, and notably remained effective against the two major Nirmatrelvir-resistant strains evaluated in this study. Mechanistic studies further confirmed kinetically stable binding and time-dependent inhibition of Y-U0-R, supporting the rationale of covalent inhibitor design. These findings highlight the utility of structure-based design for the development of promising broad-spectrum anti-coronavirus agents."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Nirmatrelvir-ritonavir targeting viral persistence in post-COVID-19 condition (long COVID) in the USA (RECOVER-VITAL): a randomised, double-blind, placebo-controlled, phase 2 trial. (PubMed, Lancet Infect Dis) - P2 | "Nirmatrelvir-ritonavir for 15 days or 25 days showed no evidence of benefit in long COVID in any of the three phenotypes studied. These findings suggest additional approaches to measuring the symptom burden and treating Long COVID are needed."

Journal • P2 data • Hypotension • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Orally Bioavailable SARS-CoV-2 Protease Inhibitors Bearing a Hydroxymethyl Ketone Warhead. (PubMed, Viruses) - "Recent efforts have mostly centered around nitrile warheads, given the success of Nirmatrelvir in the clinic. Nevertheless, early HMK-based compounds, such as the clinical-stage Mpro inhibitor PF-00835231, suffered from poor oral bioavailability and therefore required intravenous administration, with or without prodrug derivatization of the hydroxyl group. In this work, we describe our efforts to advance the HMK field by discovering mCMX110, a lead compound that exhibits superior potency, increased unbound exposure in vivo, and favorable oral bioavailability in preclinical studies."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

The Combination of Nirmatrelvir and Ivermectin Exerts Strongly Synergistic Antiviral and Anti-Inflammatory Effects Against Murine Coronavirus Infection of Macrophages. (PubMed, Int J Mol Sci) - "Conversely, the combinations of Nirmatrelvir with Azithromycin or Doxycycline exhibited only additive or mildly additive effects, with alterations in certain cytokine levels. These findings support the potential of Nirmatrelvir-Ivermectin as a promising novel combination therapy with both antiviral and anti-inflammatory benefits, warranting further in vivo validation and clinical investigation."

Journal • Preclinical • Infectious Disease • Inflammation • Novel Coronavirus Disease • Respiratory Diseases • IL1B • IL6 • TNFA

Wastewater-Based Genomic Surveillance of SARS-CoV-2 Antiviral Resistance Determinants in Ontario: Towards a Scalable Framework for Population-Level Antiviral Resistance Monitoring. (PubMed, Viruses) - "These findings demonstrate that wastewater surveillance enables population-scale monitoring of antiviral resistance and immune escape-associated mutations and offers a scalable model for broader surveillance."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Efficacy and Safety of Nirmatrelvir/Ritonavir and Molnupiravir in Non-Hospitalized Patients with COVID-19: A Single-Center Retrospective Study. (PubMed, Medicina (Kaunas)) - "Among patient-reported symptoms effects, the incidence of dysgeusia was significantly higher in patients treated with NMV/r (p = 0.001). Both antivirals showed similarly low progression, hospitalization, and mortality rates."

Journal • Retrospective data • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases