Within two years of finishing construction of Building 29, NIH began planning Building 29A as a laboratory annex. NIH's director at the time, Dr. James Shannon, described the quickening pace of vaccine development when he sought to justify to Congress his request for funds for planning Building 29A so soon after Building 29 had been completed. As previously mentioned, the DBS at the time had just established standards governing the production and testing of oral polio vaccines developed by Albert Sabin, the development of measles vaccines was well underway, and a vaccine for infectious hepatitis was thought to be on the horizon. Justifying the request, Shannon stated that, “Although laboratory testing space, including quarters for experimental animals, appeared adequate with the move in 1961 to the new Biologics Standards Building, requirements for new programs in 1962, particularly live polio virus vaccine and measles vaccine have increased considerably” (House Committee on Appropriations, Hearings on H.R. 1916, 87^th Congress, 2^nd Session, 936). NIH quantified the growth in a prepared statement, stating that, “In the past five or six years the importance of biologics control and its role in the future development of preventive and therapeutic medicines has continually grown until in 1962 the program is approximately three and one-half times larger than when the Congress authorized the construction of the first Biologics Standards Building in 1956” (Senate Committee on Appropriations, Hearings on S. 1514, 87^th Congress, 2^nd Session, 1962, 474).