Health and economic benefits of early vaccination and nonpharmaceutical interventions for a human influenza A (H7N9) pandemic: a modeling study.

Khazeni N, Hutton DW, Collins CI, Garber AM, Owens DK.

Abstract

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.

PERSPECTIVE:

Societal.

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.