At least three of the four makers of H1N1 vaccine have begun shipping their products, their representatives told CNN Tuesday. Sanofi Pasteur said Tuesday it shipped the first batch of H1N1 flu vaccine from its plant in Swift water, Pennsylvania, several days earlier than expected. Further shipments will follow, with a total of 75.3 million doses expected through December, said Donna Cary, spokeswoman for the vaccine maker. Another vaccine maker, Med Immune, shipped its first batch of 5 million doses to regional distribution centers last Tuesday, company spokeswoman Karen Lancaster said. HHS bought 40 million doses from the company, she said. Novartis began its shipments on Sunday, said spokesman Eric Althoff, who said he did not know the size of the order. "This is the first of many shipments," he said. The fourth maker, GlaxoSmithKline, did not immediately respond to a telephone call. "We will have enough vaccine available for everyone," Kathleen Sebelius told the House Energy and Commerce Committee this month.