Cost-Effective Antiviral Strategy Could Halve Pandemic Deaths

Treatment with the oral antiviral oseltamivir combined with post-exposure prophylaxis (PEP) of people exposed to infected individuals could be one of the most cost-effective strategies for reducing illness and death during an influenza pandemic according to recent modeling research published in Value in Health by Beate Sander et al., University of Toronto, Ontario, Canada.

The objective of the study was to analyze, from a US societal perspective, the potential economic impact of a number of key mitigation strategies that may be considered in the event of a pandemic.

Combined targeted antiviral treatment / PEP is a cost-saving strategy and the most effective single approach for mitigating pandemic influenza. The addition of school closure provides greater benefit. Although this remains cost-effective from a societal perspective, school closure will most likely be an attractive strategy when transmission / mortality rates are high.

This analysis is the first economic evaluation to be performed using a dynamic model to predict influenza transmission, the model being based on a "typical" American community of 1.6 million individuals. The study evaluated the use of 16 alternate strategies based on the use of oseltamivir for both treatment and post-exposure prophylaxis (PEP), the use of pre-vaccination in 70% of the population, the use of school closure to reduce the spread of disease and the absence of any intervention.

Without intervention, the authors predict that an influenza pandemic would result in ~50% of the population being infected with a mortality rate amongst infected individuals of ~1.3% and an overall economic impact to society of ~$190 per capita. To a greater or lesser extent, all of the interventions studied reduced illness attack rate, morbidity and mortality. However, the combined use of oseltamivir for treatment and PEP was shown to be the most effective single approach, reducing the number of individuals infected by ~50%, the mortality rate by ~60% at the lowest cost to society ($120 per capita). Extrapolation of these results to the broader US population (300 million) would indicate that such an intervention could result in the prevention of 81 million infections and 2.4 million deaths in the event of an influenza pandemic. Further significant improvement in disease transmission and mortality (reduced by ~88% and ~92% respectively in comparison with no intervention) can be gained by the addition of school closure to this approach but at a substantially higher overall cost to society (~$2,700 per capita).

"The World Health Organisation provides a strong recommendation for the use of oseltamivir for the prevention of avian flu in people who have been in contact with someone who is known, or suspected of being infected with the virus," commented Professor Ira Longini, Professor of Biostatistics and Mathematics at the University of Washington, Seattle, USA. "This research suggests that a similar approach may also be an effective strategy in the event of an actual pandemic outbreak, especially as it is unlikely that a vaccine fully matched to the strain will be available in the initial wave of a pandemic."

Value in Health (ISSN 1098-3015) publishes papers, concepts, and ideas that advance the field of pharmacoeconomics and outcomes research and help health care leaders to make decisions that are solidly evidence-based. The journal is published bi-monthly and has a regular readership of over 3,000 clinicians, decision-makers, and researchers worldwide.