Fascinating interview with Dr. Marsha Wills-Karp, an expert on the environmental determinants of immune diseases:
Almost no virus is protective against allergic disease or other immune diseases. In fact, infections with viruses mostly either contribute to the development of those diseases or worsen them. The opposite is true of bacteria.Pets are good, though:
We’ve also noticed that people who live on farms have fewer of these diseases because they’re exposed to — for lack of a better term — the fecal material of animals. And what we have found is that it’s due to these commensal bacteria. That is one of the components that helps us keep a healthy immune system. Most of us will probably not adopt farm life. But we can have a pet, we can have a dog.