molecules, called cytokines, which attract nearby immune cells. Those immune cells then make us
feel awful. They create inflammation that triggers a scratchy feeling in the throat and leads to the
production of a lot of mucus around the site of the infection. In order to recover from a cold, we have
to wait not only for the immune system to wipe out the virus but also to calm itself down.
The Egyptian author of the Ebers papyrus wrote that the cure for resh was to dab a mixture of
honey, herbs, and incense around the nose. In seventeenth-century England, cures included a blend of
gunpowder and eggs and of fried cow dung and suet. Leonard Hill, the physiologist who believed a
change of temperature caused colds, recommended that children start their day with a cold shower.
Today, doctors don’t have much more to offer people who get colds. There is no vaccine. There is no
drug that has consistently shown signs of killing the virus. Some studies have suggested that taking
zinc can slow the growth of human rhinoviruses, but later studies failed to replicate their results.
In fact, some treatments for the cold may be worse than the disease itself. Parents often give their
children cough syrup for colds, despite the fact that studies show it doesn’t make people get better
faster. But cough syrup also poses a wide variety of rare yet serious side effects, such as convulsions,
rapid heart rate, and even death. In 2008, the Food and Drug Administration warned that children
under the age of two—the people who get colds the most—should not take cough syrup.
Another popular treatment for the cold is antibiotics, despite the fact that they only work on
bacteria and are useless again viruses. In some cases, doctors prescribe antibiotics because they’re
not sure whether a patient has a cold or a bacterial infection. In other cases, they may be responding
to pressure from worried parents to do something. But unnecessary prescriptions of antibiotics are a
danger to us all, because they foster the evolution of increasingly drug-resistant bacteria in our bodies
and in the environment. Failing to treat their patients, doctors are actually raising the risk of other
diseases for everyone.
One reason the cold remains incurable may be that we’ve underestimated the rhinovirus. It exists in
many forms, and scientists are only starting to get a true reckoning of its genetic diversity. By the end
of the twentieth century, scientists had identified dozens of strains, which belonged to two great
lineages, known as HRV-A and HRV-B. In 2006, Ian Lipkin and Thomas Briese of Columbia
University were searching for the cause of flu-like symptoms in New Yorkers who did not carry the
influenza virus. They discovered that a third of them carried a strain of human rhinovirus that was not
closely related to either HRV-A or HRV-B. Lipkin and Briese dubbed it HRV-C, and since then,
researchers have found that this third lineage is common around the world. From one region to
another, the variations in HRV-C’s genes are few, which suggests that the virus wasted no time
spreading through our species. In fact, the common ancestor of all HRV-C may be just a few centuries
old.
The more strains of rhinoviruses scientists discover, the better they come to understand their
evolution. All human rhinoviruses share a core of genes that have changed very little as the viruses
have spread around the world. Meanwhile, a few parts of the rhinovirus genome are evolving very
quickly. These regions appear to help the virus avoid being killed by our immune systems. When our
bodies build antibodies that can stop one strain of human rhinovirus, other strains can still infect us
because our antibodies don’t fit on their surface proteins. Consistent with this hypothesis is the fact
that people are typically infected by several different human rhinovirus strains each year.