Faulty Memory: Long-term immunity isn’t always beneficial
Come down with a case of chicken pox and, after you recover, your body seems to wear an invisible suit of armor that protects you from getting the disease again. Catch a cold, on the other hand, and the protective armor seems to fall away quickly.
Common sense indicates that the longer your immune memory lasts, the healthier you will be. Now, a mathematical model indicates that there may be a good reason that you quickly lose your protection against the sniffles. The endless succession of colds that results may protect you from far nastier bugs.