Reporting from Washington - Health and Human Services Secretary Kathleen Sebelius told Congress on Wednesday that delays in the release of H1N1 flu shots show that the United States is too dependent on other countries for the manufacture of vaccines and that the technology to make them must be improved. Four of the five manufacturers of H1N1 vaccines are foreign companies -- a fact that alarmed lawmakers, who expressed concern about the ability of the federal government to secure enough vaccine to prevent the spread of the virus, known as swine flu.