The anti-vaxxer movement in a nutshell.

I admit that the chart leaves a bit to interpretation, but it also backs my own anecdotal experience.

It doesn't just leave a bit to interpretation, it shows characteristics that just don't match what your hypothesis.

But you want to defend the flu virus. So please go on and explain how flu effectiveness is underestimated.

The link I provided explained why:

To boil it down, the CDC enrolled patients who sought care for an acute respiratory illness with cough and determined what percentage of those who tested positive for flu and those who did not had been vaccinated. In essence, this is a prospective test-negative case-control design. Basically, controls were patients with a medically attended ARI who tested negative for the flu virus, while cases were patients who tested positive. The primary exposure of interest was, of course, the flu vaccine. The idea of this study is to determine whether a higher proportion of people who tested negative for the flu were vaccinated than those who tested positive.

One thing that should be pointed out. This study design does not answer the question that most people are interested in: If I get the flu vaccine, what by how much does it reduce my chances of getting the flu? Remember, this patient population consists of people who have an ARI with cough severe enough that they sought medical help for it. Of course, these people almost certainly don’t have the flu, given that by definition they have no symptoms. On the other hand this study says nothing about people with the flu or ARIs who don’t seek medical care, nor does it say anything about the ability of this vaccine to prevent severe disease, hospitalization, and death. Still, as a quick measure of effectiveness after the flu season is only halfway over, it’s not bad. Think of it this way. To determine the absolute efficacy of the flu vaccine would require following a huge number of people, vaccinated and unvaccinated, given that in an average flu season around 2% of the population will get the flu, and seeing who does and doesn’t get the flu that year. To reliably detect, say, a 50% reduction in flu would require thousands of people. Under the CDC’s study design, of people showing up at a clinic during flu season, many more will actually have the flu; so a determination of flu vaccine effectiveness can be made with a lot fewer people.

/r/funny Thread Link - i.imgur.com