Authors' objectives:

The objective of this report is to assess the cost-effectiveness of zanamivir (Relenza(R))for treating influenza in adults. Cost-effectiveness is assessed for the general population as well as for those at-risk of developing complications related to influenza.

Authors' results and conclusions: Assessing the cost-effective prescribing of zanamivir is complicated by several factors: - although treatment with zanamivir has been shown to reduce antibiotic use, there is an absence of evidence that it would reduce serious influenza-related complications resulting in hospitalization; - the difficulty in distinguishing influenza from other causes of influenza-like illnesses; - the difficulty in identifying which patients are truly at risk of developing complications and could benefit from therapy; - uncertainty about how many patients will present to physicians soon enough after the onset of symptoms so that they are treated with zanamivir within the first 48 hours. In addition, there have been recent warnings about the decline in respiratory function which may occur in those with underlying chronic pulmonary conditions. Given the large number of assumptions and incomplete information on zanamivir efficacy, as well as other factors, this study may not constitute the 'final word' in determining the cost-effectiveness of zanamivir for treating influenza. Further analysis may be warranted when additional data on the efficacy and effectiveness of the drug, particularly in high-risk groups, becomes available. Analysis using other antiviral agents as a comparator would also be useful.

Authors' recommendations: From the perspective of a government healthcare payer, the evidence suggests that it is not cost-effective to prescribe zanamivir for the treatment of influenza in those who are not at risk of influenza-related complications. Zanamivir could be cost-effective in high-risk groups, if the accuracy of diagnosing influenza is relatively high and if significant hospitalizations can be prevented - but the evidence for this is inconclusive at this time. A cause for concern is the likelihood of primary care consultations from those with little risk of complications who would not ordinarily seek treatment. Finally, if zanamivir were to be covered by a drug plan, additional budgetary resources would have to be allocated for the purchase of the drug since it is unlikely that treating high-risk patients with zanamivir will be a cost-saving strategy.

Authors' methods: Economic evaluation

Project Status: Completed

URL for project: https://www.ccohta.ca/

Year Published: 2001

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Canada

Organisation Name: Canadian Coordinating Office for Health Technology Assessment

Contact Address: 600-865 Carling Avenue, Ottawa, ON K1S 5S8 Canada. Tel: +1 613 226 2553, Fax: +1 613 226 5392;

Contact Name: requests@cadth.ca

Contact Email: requests@cadth.ca

Copyright: Canadian Coordinating Office for Health Technology Assessment