Polio vaccine poliomyelitis per million doses given. This compares with 5,000 cases per million who are paralysed following a polio infection. Both are generally safe to give during pregnancy and in those who have HIV/AIDS but are otherwise well. The first polio vaccine was the inactivated polio vaccine. It was developed by Jonas Salk and came into use in 1955. The oral polio vaccine was developed by Albert Sabin and came into commercial use in 1961. They are on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in
His Name Is Legs (Ladies and Gentlemen) for "His Name Is Legs" included tack piano, played by Canadian musician David Foster, and a new horn arrangement, played by Scott and Chuck Findley, another member of Harrison's tour band the previous year. Scott and Findley recorded their contributions at A&M Studios over 2–3 June, with each musician overdubbing two horn parts.<ref name="Extra Texture/YouTube">George Harrison interview, "Rockweek", (retrieved 13 September 2013).</ref> The released recording begins with an introductory bass riff from Weeks, which is then joined by Foster's tack piano. Commentators note the lack of clarity in the mix, which author Elliot Huntley attributes to the "three-pronged piano attack"