query: Who developed the flu shot?
passage: Influenza vaccine
In 1931, viral growth in embryonated hens' eggs was reported by Ernest William Goodpasture and colleagues at Vanderbilt University. The work was extended to growth of influenza virus by several workers, including Thomas Francis, Jonas Salk, Wilson Smith and Macfarlane Burnet, leading to the first experimental influenza vaccines.[137] In the 1940s, the US military developed the first approved inactivated vaccines for influenza, which were used in the Second World War.[138] Hen's eggs continued to be used to produce virus used in influenza vaccines, but manufacturers made improvements in the purity of the virus by developing improved processes to remove egg proteins and to reduce systemic reactivity of the vaccine.[139] Recently, the US FDA approved influenza vaccines made by growing virus in cell cultures[140] and influenza vaccines made from recombinant proteins[141] have been approved, with plant-based influenza vaccines being tested in clinical trials.[142]
passage: Influenza research
On April 17, 2007, the first US approval for H5N1 influenza vaccine for humans was given. This vaccine made by Sanofi-Aventis at a plant in Swiftwater, Pennsylvania is not to be sold commercially; instead the US is stockpiling it as an interim measure while better vaccines are being researched. Two injections given 28 days apart gave evidence of providing protection for 45 percent of the people who got the vaccine in a study. "The U.S. Department of Health and Human Services said it had already purchased 13 million doses of the Sanofi vaccine, enough to inoculate 6.5 million people. The vaccine was approved for people age 18 to 64. Studies in other age groups are ongoing. The most common side effects reported were pain at the injection site, headache, general ill feeling and muscle pain, the FDA said."