American Journal of Epidemiology Advance Access originally published online on April 24, 2009
American Journal of Epidemiology 2009 169(12):1517-1524; doi:10.1093/aje/kwp072
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PRACTICE OF EPIDEMIOLOGY |
Optimal Dosing and Dynamic Distribution of Vaccines in an Influenza Pandemic
Correspondence to Dr. James Wood, School of Public Health and Community Medicine, University of New South Wales, NSW 2052, Australia (e-mail: james.wood{at}unsw.edu.au).
Received for publication May 13, 2008. Accepted for publication March 9, 2009.
Limited production capacity and delays inherent in vaccine development are major hurdles to the widespread use of vaccines to mitigate the effects of a new influenza pandemic. Antigen-sparing vaccines have the most potential to increase population coverage but may be less efficacious. The authors explored this trade-off by applying simple models of influenza transmission and dose response to recent clinical trial data. In this paper, these data are used to illustrate an approach to comparing vaccines on the basis of antigen supply and inferred efficacy. The effects of delays in matched vaccine availability and seroconversion on epidemic size during pandemic phase 6 were also studied. The authors infer from trial data that population benefits stem from the use of low-antigen vaccines. Delayed availability of a matched vaccine could be partially alleviated by using a 1-dose vaccination program with increased coverage and reduced time to full protection. Although less immunogenic, an overall attack rate of up to 6% lower than a 2-dose program could be achieved. However, if prevalence at vaccination is above 1%, effectiveness is much reduced, emphasizing the need for other control measures.
disease outbreaks; influenza, human; mass immunization; models, theoretical