Mark Mulligan leads Emory swine flu vaccine trial. Interview by Brooke Grindlinger.

Fearing that the fall flu season in combination with the return of children to school could trigger a spike in swine flu cases, the National Institute of Allergy and Infectious Diseases has begun clinical trials of candidate vaccines against the pandemic influenza (H1N1) virus. The JCI spoke with Mark Mulligan (Figure 1), professor of medicine at Emory University School of Medicine and principal investigator at the Emory Vaccine Center’s Vaccine and Treatment Evaluation Unit (VTEU), one of eight in a nationwide network of VTEUs where the trials will be conducted. JCI: The Emory Vaccine Center is experienced in developing candidate vaccines for HIV, malaria, and H5N1 avian influenza. So is this business as usual for your team? Mulligan: No, not by any means. These are extraordinary circumstances. We are in the midst of a public health emergency, and the sense of urgency to control this pandemic is greater than anything I’ve experienced in my career. JCI: What are the primary objectives of this trial? Mulligan: We hope to determine the strength (15 μg vs. 30 μg) and number of doses (one vs. two) of the vaccine required to stimulate an immune response likely to protect against H1N1 flu. We will evaluate vaccine safety and immunogenicity in five different age groups: 6 to 35 months, 3 to 9 years, 10 to 17 years, 18 to 64 years, and adults 65 years and older. We also hope to determine how best to give the H1N1 vaccine safely in combination with the seasonal flu vaccine and without reducing the immune response to either. JCI: Do you anticipate children, adults, and seniors responding differently to the vaccine? Mulligan: The influence of age has been very interesting in this pandemic. The burden of disease has been in children and young adults, while seniors have been mostly spared. Seniors may have had previous exposure to an H1N1-like virus that primed their immunological memory, providing a level of protection against H1N1. This could influence their response to vaccine; they may only require one dose. If true, this could be very important during the early stages of vaccine deployment if supply is limited. JCI: What have been some of the challenges in producing this vaccine? Mulligan: Influenza is unpredictable, and there are always difficulties with the manufacturing process. The efficiency with which the vaccine strain grows in embryonated hens’ eggs has only been about 30% of what is considered optimal. Over time that rate often improves; however, we don’t have the luxury of time on this occasion. JCI: When is a vaccine estimated to be available? Mulligan: Eighty million doses are projected to be available in September and 120 million in October. The vaccine will be held by the federal government and deployed by state governments depending on when it is needed.