Oseltamivir Plus Usual Care versus Usual Primary Care for Influenza-Like-Illness: An Open-Label, Pragmatic, Randomized Controlled Trial

Background: Antivirals are infrequently prescribed in primary care for influenza-like-illness (ILI), mostly because of perceived ineffectiveness in real world primary care, and as individuals who will especially benefit have not been identified in independent trials. We aimed to determine whether adding antiviral treatment to usual primary care for patients with ILI reduces time to recovery overall and in key subgroups. Methods: We conducted an open-label, pragmatic, randomized controlled trial of adding oseltamivir to usual care in patients aged one year and older consulting with ILI in primary care. The primary endpoint was time to recovery (return to usual activities, with fever, head- and muscle-ache minor/absent), following a Bayesian piece-wise exponential model. Baseline nasopharyngeal swabs were analyzed after study completion. Findings: We ascertained the primary outcome for 3059 of the 3266 participants recruited in 15 European countries during three seasonal influenza seasons (2015-2018); 52.0% (1590/3059) had PCR-confirmed influenza infection. Time to recovery was shorter in those given oseltamivir by 1.02 days (95% Bayesian CI: 0.73-1.32). Hazard ratios of proportional benefit were similar across pre-specified subgroups; absolute benefit in time to recovery varied, with an estimated benefit of >2 days in older patients, more severe illness, comorbidity, or longer prior illness duration. The effect was independent of influenza status. Fewer antibiotics were prescribed in the oseltamivir arm (9.3% vs 13.2%, mean difference 4.0; 95% CI: 1.7-6.3), while nausea and/or vomiting was shorter in usual care patients (HR 0.92; 95% CI: 0.85-1.00). Interpretation: Primary care patients with ILI treated with oseltamivir recovered sooner than those managed by usual care alone, irrespective of influenza virus test results. Older, sicker, patients with comorbidities and longer prior illness duration showed greater absolute benefit. Trial Registration: The trial is registered with the ISRCTN Registry, number ISRCTN27908921. Funding Statement: CB reports receiving advisory board fees from Roche Molecular Systems and grant support from Roche Molecular Diagnostics; CB was supported by funding from an NIHR Protection Research Unit on Health Care Associated Infections and Antimicrobial Resistance, by the NIHR MedTech and In Vitro Diagnostics Co-Operative at Oxford NHS Foundation Trust, and by an NIHR Senior Investigator Award. TV is PI in a project that is funded by Innovative Medicines Initiative (IMI) of the European Union, in which Janssen Pharmaceutica is a partner and researcher in another IMI project in which Biocartis, Janssen, Biomerieux and Berry Consultants are partners. In addition he is co PI of a NIHR funded RCT, and PI in several studies funded by the Netherlands Organization of Health Research and Development. CL has received advisory boards fees from MSD and grant support from GILEAD, Global Bridges, Servier, Galenica-Olvos. Declaration of Interests: CB reports receiving advisory board fees from Roche Molecular Systems and grant support from Roche Molecular Diagnostics; CB was supported by funding from an NIHR Protection Research Unit on Health Care Associated Infections and Antimicrobial Resistance, by the NIHR MedTech and In Vitro Diagnostics Co-Operative at Oxford NHS Foundation Trust, and by an NIHR Senior Investigator Award. TV is PI in a project that is funded by Innovative Medicines Initiative (IMI) of the European Union, in which Janssen Pharmaceutica is a partner and researcher in another IMI project in which Biocartis, Janssen, Biomerieux and Berry Consultants are partners. In addition he is co PI of a NIHR funded RCT, and PI in several studies funded by the Netherlands Organization of Health Research and Development. CL has received advisory boards fees from MSD and grant support from GILEAD, Global Bridges, Servier, Galenica-Olvos. All other authors declare no conflict of interest. Ethics Approval Statement: All participating countries gained national research ethics committees and CTA approval as required. Ethics Ref: 15/SC/0138.