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It is heartening to apparently see reports materializing from several clinical trials of 2009 H1N1 influenza vaccines. These trials were apparently conducted by several vaccine manufactures. Many more companies may declare the outcome of their preliminary trials in sometime.

The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, may also be carrying out clinical trials of 2009 H1N1 influenza vaccines, which seem to be produced by Sanofi Pasteur and CSL Limited. The premature information from these trials could point out that 2009 H1N1 influenza vaccines may be well tolerated and could provoke a powerful immune response in almost all healthy adults when they were apparently administered a single unadjuvanted 15-microgram dose.

The NIAID trials may be testing two diverse dosages i.e. 15 micrograms versus 30 micrograms and supposedly assessing the immune response to one and two doses of these vaccines. Apparently more than 2,800 people may be taking part in the continuing NIAID trials of these vaccines.

After vaccination, the blood samples were obtained after 8-10 days. Among healthy adults who apparently received a single 15-microgram dose of the Sanofi Pasteur vaccine, a healthy immune response was supposedly measured in 96 percent of adults who were between 18 – 64 years and in about 56 percent of adults who were 65 years or more. Likewise, among healthy adults who claimed to have received a single 15-microgram dose of the CSL Limited vaccine, a healthy immune response was supposedly measured in approximately 80 percent of adults from 18 – 64 years and in roughly 60 percent of adults who may be 65 years and older.

Supplementary data from the NIAID trials may be helpful. Nevertheless, on the foundation of these strong early data, the outcome is supposedly consonant with other reports that a single 15-microgram dose of unadjuvanted 2009 H1N1 influenza vaccine may be well tolerated and could provoke a healthy immune response in adults between the ages of 18 and 64. The immune response to 2009 H1N1 influenza vaccine may be rather less healthy, as is the case with seasonal influenza vaccines in adults between the ages of 16 and 64.

It may be observed that minor inconsistencies could be seen in the trials betwewen the Sanofi Pasteur and CSL Limited vaccines. This may be due to technical differences in the initial measurement of the quantity of antigen in the doses apparently used in the clinical trial lots and the comparatively restricted numbers of samples studied to date. It may also be due to the fact that the data may be drawn from a very early time point post immunization.

NIAID may continue to supply timely updates on these trials as well as those in children and in pregnant women, which may start afterwards.