AUSTIN, Texas-When faced with potential vaccine shortages during a flu outbreak, public health officials can turn to a new study by mathematical biologists at The University of Texas at Austin to learn how to best distribute the vaccine.
The scientists used contact network epidemiology to model various vaccine distribution strategies, including the United States Centers for Disease Control strategy of targeting high-risk groups, like infants, the elderly and people with health complications. They also tested the idea of targeting school children, who are critical vectors in moving diseases through communities.
They found that the best vaccine distribution strategy depends on the contagiousness of the flu strain.
"If we only have a limited flu vaccine supply, the best distribution strategy depends on the contagiousness of the strain," says Dr. Lauren Ancel Meyers, assistant professor of integrative biology. "We can more effectively control mildly contagious strains by vaccinating school children, while we can more effectively control moderately and highly contagious strains by vaccinating high-risk groups."
If there is no information available about the contagiousness of a flu strain or if the vaccines are only available after the outbreak is underway, the study recommends prioritizing vaccines for those people in high-risk groups who can experience the greatest complications due to the disease.
Meyers and her colleagues based their contact network models on information from Vancouver, British Columbia. While other mathematical models of disease transmission assume all members of a community are equally likely to infect each other, contact network models take the relationships among people into account.
Meyers says this allowed them to make more detailed and reliable predictions about infectious disease transmission.
"Given that vaccine shortages are likely (as occurred at the start of the 2004 flu season) and that we are unlikely to have a large vaccine supply if a new strain of pandemic flu emerges in human populations, this study offers quantitatively grounded recommendations for public health officials who may be forced to make rapid life-and-death decisions," says Meyers.
University of Texas at Austin. October 2006.