Background: Vaccination for the 2009 pandemic did not occur until late in the outbreak, which limited its benefits. Influenza A (H7N9) is causing increasing morbidity and mortality in China, and researchers have modified the A (H5N1) virus to transmit via aerosol, which again heightens concerns about pandemic influenza preparedness.
Objective: To determine how quickly vaccination should be completed to reduce infections, deaths, and health care costs in a pandemic with characteristics similar to influenza A (H7N9) and A (H5N1).
Design: Dynamic transmission model to estimate health and economic consequences of a severe influenza pandemic in a large metropolitan city.
Data Sources: Literature and expert opinion.
Target Population: Residents of a U.S. metropolitan city with characteristics similar to New York City.
Time Horizon: Lifetime.
Intervention: Vaccination of 30% of the population at 4 or 6 months.
Outcome Measures: Infections and deaths averted and cost-effectiveness.
Results of Base-Case Analysis: In 12 months, 48 254 persons would die. Vaccinating at 9 months would avert 2365 of these deaths. Vaccinating at 6 months would save 5775 additional lives and $51 million at a city level. Accelerating delivery to 4 months would save an additional 5633 lives and $50 million.
Results of Sensitivity Analysis: If vaccination were delayed for 9 months, reducing contacts by 8% through nonpharmaceutical interventions would yield a similar reduction in infections and deaths as vaccination at 4 months.
Limitation: The model is not designed to evaluate programs targeting specific populations, such as children or persons with comorbid conditions.
Conclusion: Vaccination in an influenza A (H7N9) pandemic would need to be completed much faster than in 2009 to substantially reduce morbidity, mortality, and health care costs. Maximizing non-pharmaceutical interventions can substantially mitigate the pandemic until a matched vaccine becomes available.
Primary Funding Source: Agency for Healthcare Research and Quality, National Institutes of Health, and Department of Veterans Affairs.