Daily vitamins are of no value.

Be sceptical, ask questions, demand proof. Demand evidence. Don't take anything for granted. But here's the thing: When you get proof, you need to accept the proof. And we're not that good at doing that.

I started to write about science and medicine at the Washington Post, in the early days of the AIDS epidemic.

Daily vitamins are of no value.

Vaccination is a public health issue because influenza is a highly contagious disease. If you don't vaccinate your child, his or her schoolmates are much more likely to become ill. That is why some places (New York, for example) are making the vaccine mandatory for school children.

Flu is easily transmitted, so if you are working with sick people - who are most at risk for getting seriously ill - you ought to be vaccinated. I am not really equipped to say whether it should be the law or not.

Benjamin Franklin refused to have one of his children vaccinated against smallpox. The four-year-old boy died, and Franklin wrote later of how mistaken he was to expose him to the needless risk.