The best way to assess flu trials is to look at those that compared vaccinated people with unvaccinated people.
When Jefferson and his colleagues published their March 2014 review they found that under ideal conditions (when the vaccine matches the main viruses circulating that season) you need to vaccinate 33 healthy adults to avoid one set of influenza symptoms. This is what we’d call a NNV (Numbers needed to Vaccinate) of 33. When the vaccine match isn’t so good as it was last year, the NNV is about 100. That is, of 100 people vaccinated, 99 will have no benefit and one person will avoid one set of influenza symptoms. Vaccination did not seem to affect the number of people hospitalised or who lost working days.
Almost half (15 of the 36 trials they examined) were funded by vaccine companies and four had no funding declaration. His team cautioned that even these numbers may represent an “optimistic estimate” because “company-sponsored influenza vaccines trials tend to produce results favorable to their products.” You can read more details here.
As for the magical “60?” Dr. Tom Jefferson didn’t mince words: “Sorry I have no idea where the 60% comes from – it’s either pure propaganda or bandied about by people who do not understand epidemiology. In both cases they should not be making policy as they do not know what they are talking about,” he said, insisting that I quote him.