Michael Specter

When most members of a community are vaccinated, they protect those who are not by eliminating the viral reservoirs in the population. The effect is known as 'herd immunity.'

The numbers matter: underreporting of Lyme disease obscures the true burden of the illnesses, on individuals as well as on health-care systems. It also makes it harder to convince Congress to fund research.

I moved from Moscow to Rome with my family and two bicycles in 1998, and spent a lot of that year- and the next - obsessed, I am sorry to admit, with the bicycles. Italy, after all, was a place where thousands of middle-aged men felt perfectly comfortable spending many hours a week in brightly colored spandex.

We're lying ourselves into believing things are untrue, like organic food will solve all our problems, or vitamins will make us healthy, or we don't need to vaccinate our children.

Why do people refuse to vaccinate their children against measles or whooping cough? In many cases, because they have never seen measles and have no idea what it might do.

Natural' is a word that has become unmoored by its meanings. If you go into a vitamin shop, things are natural, and people look at that, and they think it's good. It's no different than any other thing you swallow.

If people want to believe that our ancestors were riding around on dinosaurs or that the protracted, increasing, and devastating warming of the Earth is just nature doing its thing - I guess I feel I have more useful battles to fight.

The most blatant forms of denialism are rarely malevolent; they combine decency, a fear of change, and the misguided desire to do good - for our health, our families, and the world. That is why so many physicians dismiss the idea that a patient's race can, and often should, be used as a tool for better diagnoses and treatment.

Deliberately modifying the earth's atmosphere would be a desperate gamble with significant risks. Yet the more likely climate change is to cause devastation, the more attractive even the most perilous attempts to mitigate those changes will become.

Most reputable scientists agree that climate change is real and that the effects are likely to be bad. But nobody can say for sure exactly what 'bad' means. The safest and most equitable way out of this horrific mess is simple: cut fossil-fuel emissions.

The best way to deal with climate change has been obvious for years: cut greenhouse-gas emissions severely. We haven't done that. In 2010, for example, carbon emissions rose by six per cent - the largest such increase on record.

Some people will deny anything that displeases or scares them: unusual pain in their chests, unwanted lumps beneath their skin, or the fact that humans share ancestry with apes are a few examples. Another is climate change.