R. Prasad CHENNAI: Preliminary analyses of the early data from two vaccine trials in the U.S. have shown that the 2009 influenza A(H1N1) vaccines are safe and the immune responses produced are robust. , The preliminary results from these two trials are similar to those of the two vaccines that are being tested in the U.K. and Australia. The results of the U.K. and Australia trials were published in the latest online issue of the New England Journal of Medicine. According to Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases 6NIAID), part of the National Institutes of Health, U.S., the vaccines tested are safe and have produced robust immune responses among healthy adults in the 18-64 age group. The NIAD is conducting the two trials in the U.S, with the participation of more than 2,800 people. Doctors and healthcare workers in a few countries have expressed fears about the safety of the vaccines, which are being tested on a fast-track mode in different countries. The trials have shown that a single dose of 15 microgram could produce robust immune responses 8-10, days after vaccination. The vaccines tested in the U.K. and Australia have showed similar results. The Sanofi Pasteur vaccine could produce a robust immune response in 96 per cent of the adults aged 18-64, and in 56 per cent of the adults aged 65 and above. In the case of the CSL Limited vaccine, a robust immune response was measured in 80 per cent of the adults aged 18-64, and in 60 per cent of the adults aged 65 and above. The two trials have shown that the immune response to the 2009 H1N1 influenza vaccine has been somewhat less robust for adults aged 65 and over. According to the NIAID, the reduced immune response among adults over 65 is similar to what is seen with the seasonal influenza vaccines. ,