FILE - In this Monday, May 25, 2020 file photo, a vile of a COVID-19 vaccine candidate on a shelf during testing at the Chula Vaccine Research Center, run by Chulalongkorn University in Bangkok, Thailand. Refrigeration, cargo planes, and, above all, money: All risk being in short supply for the international initiative to get coronavirus vaccines to the world’s most vulnerable people. (AP Photo/Sakchai Lalit, File)

FILE - In this Wednesday, June 24, 2020 file photo, a volunteer receives an injection at the Chris Hani Baragwanath hospital in Soweto, Johannesburg. Refrigeration, cargo planes, and, above all, money: All risk being in short supply for the international initiative to get coronavirus vaccines to the world’s most vulnerable people. (Siphiwe Sibeko/Pool via AP, File)

FILE - In this Wednesday, June 24, 2020 file photo, a medical staff member prepares a syringe, at the Chris Hani Baragwanath hospital in Soweto, Johannesburg. Refrigeration, cargo planes, and, above all, money: All risk being in short supply for the international initiative to get coronavirus vaccines to the world’s most vulnerable people. (AP Photo/Siphiwe Sibeko, File)

FILE - In this Wednesday, June 24, 2020 file photo, a medical worker addresses some of the first vaccine volunteers, at the Chris Hani Baragwanath hospital in Soweto, Johannesburg. Refrigeration, cargo planes, and, above all, money: All risk being in short supply for the international initiative to get coronavirus vaccines to the world’s most vulnerable people. (AP Photo/Siphiwe Sibeko, File)

FILE - In this July 30, 2020 file photo, Kai Hu, a research associate transfers medium to cells, in the laboratory at Imperial College in London. Imperial College is working on the development of a COVID-19 vaccine. Refrigeration, cargo planes, and, above all, money: All risk being in short supply for the international initiative to get coronavirus vaccines to the world’s most vulnerable people. (AP Photo/Kirsty Wigglesworth, File)