Low rate of oseltamivir prescription among adults and children with confirmed influenza illness in France during the 2018-19 influenza season

Background: Oseltamivir shows effectiveness in reducing influenza-related symptoms, morbidity and mortality. Its prescription remains suboptimal.

Objectives: We aim to describe oseltamivir prescription in confirmed cases of influenza and to identify associated factors.

Methods: A prospective monocentric observational study was conducted between 1 December 2018 and 30 April 2019. All patients with a virologically confirmed influenza diagnosis were included. Factors associated with oseltamivir prescription were studied.

Results: Influenza was confirmed in 755 patients (483 children and 272 adults), of which 188 (25.1%) were hospitalized and 86 (11.4%) had signs of severity. Oseltamivir was prescribed for 452 patients (59.9%), more frequently in children than in adults [329/483 (68.1%) versus 123/272 (45.2%), P < 0.001]. Factors associated with oseltamivir prescription were evaluated in 729 patients (246 adults and 483 children). Patients with at least one risk factor for severe influenza received oseltamivir less frequently (50%, 137/274) than those without risk factors (70%, 315/452) (P < 0.001). Pregnant women received oseltamivir in 81% of cases (17/21). Severe influenza cases were treated with oseltamivir in only 45.3% (39/86). The median duration of symptoms was 24 h (IQR 12-48) in treated patients versus 72 h (IQR 48-120) in untreated patients (P < 0.01).

Conclusions: Oseltamivir should be administered as early as possible, preferably within 24-48 h after illness onset, for the best benefits. It is, however, very important to promote the use of neuraminidase inhibitor ('NAI') treatment beyond 48 h in some specific patient populations.