Posted by Kromey at 9:39pm Oct 9 '09The press conference and press releases discussed an analysis that included all 16,000 people who participated in the trial, except for seven who were infected before receiving any doses of the two vaccines that were used in combination. Seventy-four people in the placebo arm of the study became infected with HIV, while the similarly sized vaccinated group only had 51 infectionsââ¬âa 31.2% efficacy. The analysis indicated that there was about a 96% level of confidence that the effect was real and not due to chanceââ¬âjust above the 95% cutoff that is widely used as a measure of statistical significance.
In the private briefings, researchers learned that a second analysis, which is usually performed in vaccine studies and was part of the Thai studyââ¬â¢s design, also found that vaccine recipients had fewer infections, but the reduction was not statistically significant and the level of efficacy was slightly lower. This analysis eliminated people in both groups who did not rigorously follow the protocols. ââ¬ÅAnything that really works, youââ¬â¢ll have enough robustness in results to be significant with both analyses,ââ¬ï¿½ says Douglas Richman, an AIDS researcher at the University of California, San Diego, a longtime critic of the study. Richman did not discuss the specific results with Science.
This isn't to say that the trial is a complete waste of time and money, but it certainly begs the question of why this second analysis was omitted from the press conference, and highlights why we should always be extremely critical of science reporting in the media.