Kalam : Research on a vaccine for preventing HIV infection should be given priority defence scientist and secretary, departmen of defence research and development, A P J Abdul Kalam said on Friday while inaugurating the third international AIIMSONIANS conference at the All India Institute of Medical Scienices. Acknowledging that AIDS posed a serious problem for the country, Mr Kalam said that even though 43 vaccines had been developed by the US and some of these had been short-listed, these vaccines may not be appropriate for Indian strains as they had been found to be different.