Epidemiologists become demographers in a disaster: Health and demographic estimation after Hurricane Katrina

Context: In the aftermath of a disaster, demographic estimates are essential to inform all sectors of health and recovery planning. With baseline census data invalidated by the disaster, health planners must be prepared to assume the role of demographer and epidemiologist by producing a ‘denominator' to supplement prevalence-based health data.

To support recovery planning after Hurricane Katrina, local health planners and technical advisors from the US Centers for Disease Control and Prevention conducted household surveys in New Orleans producing four citywide population estimates between October 2005 and October 2006.

Research: Three sampling methods were used to produce the household health and demographic estimates. A model for predicting household return rates based on food depths and time since the events was also developed from the household survey data using geographic information systems (GIS).

Results: The surveys identified a household population of 106,000 residents two months after Katrina at the end of October 2005; 134,400 one month later; 181,400 five months after Katrina, and 191,100 residents approximately ten months after Katrina. The results of a model for predicting household occupancy rates based on the survey data is also presented.

Conclusion: The sampling and survey methods described provide health planners with tools for rapidly producing household demographic estimates after a disaster. The predictive model which is also presented provides health planners with a scientific means for predicting household return in the immediate aftermath of a major flood event.