Abstract
Controversy has arisen regarding the effectiveness of neuraminidase inhibitors (NIs), especially against influenza-related complications. A literature search was performed to critically assess the evidence collected by the available systematic reviews (SRs) regarding the benefits and disadvantages of NIs (oseltamivir, zanamivir) compared to placebos in healthy and at-risk individuals of all ages for prophylaxis and treatment of seasonal influenza. A SR was done using the Cochrane Database of Systematic Reviews, Health Technology Assessment Database, Database of s of Reviews of Effects, and Medline (January 2006–July 2012). Two reviewers selected SRs based on randomized clinical trials, which were restricted to intention-to-treat results, and they assessed review (AMSTAR) and study quality indicators (GRADE). The SRs included (N = 9) were of high quality. The efficacy of NIs in prophylaxis ranged from 64% (16–85) to 92% (37–99); the absolute risk reduction ranged from 1.2% to 12.1% (GRADE moderate to low). Clinically relevant treatment benefits of NIs were small in healthy adults and children suffering from influenza-like illness (GRADE high to moderate). Oseltamivir reduced antibiotic usage in healthy adults according to one SR, but this was not confirmed by other reviews (GRADE low). Zanamivir showed a preventive effect on antibiotic usage in children (95% (77–99);GRADE moderate) and on the occurrence of bronchitis in at-risk individuals (59% (30–76);GRADE moderate). No evidence was available on the treatment benefits of NIs in elderly and at-risk groups and their effects on hospitalization and mortality. In oseltamivir trials, nausea, vomiting and diarrhea were significant side-effects. For zanamivir trials, no adverse effects have been reported. The combination of diagnostic uncertainty, the risk for virus strain resistance, possible side effects and financial cost outweigh the small benefits of oseltamivir or zanamivir for the prophylaxis and treatment of healthy individuals. No relevant benefits of these NIs on complications in at-risk individuals have been established.
Highlights
In non-high-risk individuals, seasonal influenza is a self-limiting disease
systematic reviews (SRs) mainly based on randomized clinical trials (RCTs) that discussed the use of neuraminidase inhibitors (NIs) for the prophylaxis and treatment of seasonal influenza and that evaluated NIs versus placebos in healthy adults, children, elderly and at-risk individuals were considered
The seasonal prophylaxis against influenza showed a significant efficacy of 76% for oseltamivir (GRADE moderate) corresponding with an absolute risk reduction (ARR) of 3.6% and 68% for zanamivir (GRADE moderate) – ARR = 4.1%
Summary
In non-high-risk individuals, seasonal influenza is a self-limiting disease. Some people, such as the elderly, young children and people with concomitant morbidities, are at a higher risk for developing serious flu complications. Efficacy reaches only 40% in the elderly and there is limited good-quality evidence of the vaccine effectiveness on complications, such as pneumonia, hospitalization and influenza specific and overall mortality [2,3,4,5]. Specific antiviral agents against influenza could be useful [1] for the treatment of or pre2/post-exposure prophylaxis for seasonal or pandemic influenza. The alleviation of symptoms, the reduction of antibiotic usage and the reduction of influenza-related complications such as bronchitis, otitis media, pneumonia, hospitalization and mortality are clinically relevant targets of their effect
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
