Sometimes it hits by surprise. Other times, it creeps up slowly. Either way, it makes you miserable once, twice, even a half-dozen times a year.
In the course of a year, Americans suffer 1 billion colds, according to researchers at the Centers for Disease Control and Prevention's National Center for Health Statistics. That means 24 million days of restricted activity; 20 million missed school days; and countless throat lozenges, boxes of tissues and cups of tea.
In the 21st century, when genes for cancer have been identified, cloning is a reality and microsurgery is commonplace, why must people suffer from something that seems so basic? For starters, colds are more complicated than people think. What seems like one illness actually is many different ones.
"The most common type of cold virus is the rhinovirus, and there are more than 100 different types of those," says Owen Hendley, a professor of pediatrics at the University of Virginia and a cold researcher for more than 30 years. "Even if you become immune to one type, there are still 99 others."
Still, researchers are working on finding the common denominator for all the viruses. Scientists at the National Institutes of Health (NIH), for example, are looking to block the virus from entering the cells, says Linda Lambert, cold and flu program officer for NIH's National Institute of Allergy and Infectious Disease.
From the time a cold virus enters the nasal cells, it takes eight to 12 hours to reproduce and be released in nasal secretions, Hendley says. Cold symptoms begin in another 10 to 12 hours, and symptoms peak 36 to 72 hours later. Those symptoms -- the runny or stuffy nose, sore throat, sneezing, cough and headache -- are the result of the body's immune response to the viral invasion.
"All viruses have to get into cells and get out," says Lambert. "We have several investigators looking at the way viruses interact or are attached to the host cells of the respiratory tract. We have several investigators trying to block that interaction." Experiments are still in the early phases, adds Lambert. "In the near future, I don't see a common-cold vaccine."
Researchers in the past hoped interferon (a substance produced in the body that can enhance immunity) and steroids would limit a cold virus' impact. "We thought we could reduce a cold with interferon," says Hendley, "but we found we couldn't alter the symptoms. Our guess was the symptoms were an inflammatory response to the viral infection.
"So we tried to treat the inflammatory response with steroids. We gave steroids to patients before and during a cold. We found a dampening of the symptoms, but then they got worse. The symptoms were just as bad as if the patients had not gotten steroids."
Hendley is cautiously encouraged by tests involving a combination of antiviral drugs and anti-inflammatories. "We're discovering that just attacking part of the cold virus doesn't settle it," he says. "It used to be that antivirals were not effective without causing other damage to people, but there are some new antivirals that have virtually no toxicity. So I am impressed we are finally getting somewhere."
Until a vaccine or cure for the common cold is found, it is important to understand how best to avoid it, Lambert says. Of course, since colds almost are unavoidable, it's also helpful to learn to manage symptoms.
Colds are spread mainly through contact with an infected person's nasal secretions. That means if he sneezes into the air or touches his nose and then another surface -- such as a pen or a doorknob -- those around him become vulnerable.
Persons with a cold should try to sneeze or cough into a tissue to keep virus particles contained. If someone in the home has a cold, surfaces can be decontaminated with disinfectant. Even with the best cleaning efforts, however, the rest of the household might pick up the germs. …