Wednesday, October 21, 2009

Chinese trial of H1N1 vaccines/NEJM

A 2200 subject trial of Chinese H1N1 vaccines (developed from the same CDC virus as vaccines developed by western manufacturers) was published in the NEJM.  Four strengths of antigen were used in 4 age groups, with and without an aluminum phosphate (not a novel) adjuvant.

Of interest:  15 mcg of antigen was sufficient.  (This is the US dose being used.)  The aluminum adjuvant did not improve antibody levels.  (No aluminum adjuvant is included in the US vaccine.)  Children under 12 had the lowest antibody titres, but boosted well following a second dose.

The study only looked at antibody titres, and (like other reported studies) did not study how protective the vaccine was at preventing cases of swine influenza.

The placebo really was a placebo (phosphate buffered saline) unlike most western vaccine trials that use a different vaccine as the control.  With a true placebo, it became apparent that systemic reactions were 3-4 times higher in the vaccine group as compared to the placebo group.  True placebo groups need to be included in US vaccine trials, for without them the true reaction rates cannot be determined.

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