A violent sneeze carries a rush of rhinoviruses out of the nose as the cold sufferer grabs a tissue to get some relief. It doesn't help much.
Instead, thousands of viruses impregnate the tissue. Hundreds more pass through it and lodge on the cold victim's hand. Unknowingly, the victim smears viruses around the house -- on table tops, pencils, glasses, eating utensils.
Each virus can survive the harsh environment outside the human body for hours until it catches a ride on the next passing hand. A spouse clearing the breakfast dishes picks up a spoon richly contaminated with rhinovirus. Some rub off.
An itch brings that hand to sleepy morning eyes and with a rub a few viruses are deposited on the eye's moist membranes. There, tears will carry the invaders down a passageway from the inside corner of the eye to an inner chamber of the nose.
Finally, the rhinovirus reaches the nose's susceptible cells. Quickly, the invader commandeers the metabolic machinery of the invaded cell and begins to produce hundreds of new viruses. Then, in a great lethal rupture, the invaded cell dies and releases new viruses to spread the infection.
In 36 to 40 hours, the symptoms begin: runny nose, scratchy throat, coughing. The cold has claimed another victim.
Colds affected more than 70 million Americans in 1982, according to the National Center for Health Statistics. But the total may be higher, and one Cleveland study estimates that people suffer an average of six colds a year, with children suffering as many as 12 colds a year.
There is no effective treatment to shorten the duration of a cold, nor is there a vaccine to prevent it. Colds are caused by more than 200 different viruses, making a single treatment for all of them extremely unlikely.
But last week, scientists from Virginia and Adelaide, Australia, announced what appears to be the first effective drug to prevent a cold: interferon. Application of a few squirts prevents symptoms of a rhinovirus infection 80 percent of the time.
However, since rhinoviruses cause only 30 to 40 percent of all colds during the year -- the rest are caused by another 100 different kinds of virus -- the interferon treatment was able to prevent other family members from becoming infected only 39 percent of the time.
"It clearly is not the cure for the common cold," said Dr. Frederick G. Hayden from the University of Viriginia School of Medicine and director of the study. "What this study demonstrates, for the first time, is two things: It is possible to prevent the transmission of rhinovirus colds in the family setting. Short-term use (of interferon) during exposure to a cold is effective in reducing the risk of developing an infection, and is generally well tolerated."
"This (report) takes interferon a step nearer to being a drug for patients," said Dr. Thomas Merigan, an interferon researcher at Stanford University Medical Center. "It is an important step because it has shown that interferon may really have a usefulness for patients with a cold."
But the good news is mixed with bad.
"One of the disappointing aspects of the study was that interferon did not protect against influenza virus or other related viruses," Hayden said. And the protection it did provide against rhinovirus lasted only as long as the interferon spray was being used. Unlike a vaccine, interferon does not provide long-lasting immunity to a virus.
The world first learned of interferon in 1957, when British virologist Alick Isaacs and his Swiss collaborator, Jean Lindenmann, announced the discovery of a family of proteins, produced by virtually every cell in the body, that could "interfere" with the ability of many different kinds of viruses to infect nearby cells.
In some ways, interferon, which is a part of the body's natural immunological defenses, is like an air raid siren. When a virus invades a cell, it induces the infected cell to produce interferon. The interferon leaks out and spreads to uninfected nearby cells. It warns those cells that viruses are nearby and stimulates them to produce a group of proteins often referred to as "antiviral proteins," which protect the cell from the virus. The exact protective mechanism of those proteins remains unknown.
Until the mid-1970s, interferon research was limited by the protein's scarcity. That changed when the American Cancer Society paid several million dollars for small amounts of interferon to test in cancer patients.
Because of that interest, emerging biotechnology companies chose interferon as one of their first products.
New availability allowed researchers to test interferon's ability to stop colds, influenza and other infections. There were two basic approaches: use interferon to treat infections, or use to to prevent them.
In experiments on volunteers, the Virginia researchers showed that interferon reduced the weight of nasal mucus production by 25 to 50 percent and reduced viral shedding when given 28 hours after rhinovirus was squirted into their noses, but before symptoms actually appeared. But the interferon treatment "did not have much effect on the symptomatic illness," said Dr. Jack M. Gwaltney Jr., head of the division of epidemiology and virology at the University of Virginia School of Medicine.
Several researchers believe that interferon -- or any antiviral drug -- never will be very effective in shortening the symptoms of a cold once they appear because by the time symptoms appear, it's too late.
"The whole cycle of infection is very short," said Stanford's Merigan. "We have to get in there early."
After the initial infection, it takes about 36 hours for the first symptoms, and the highest concentration of virus, to appear. That also is the time that the victim is most contagious. "In three days, from the moment the symptoms appear, the concentration of virus is falling due to normal defenses," said Merigan. "The rest of the symptoms are the recovery of the nose and throat from the infection and some of the body's response."
The Virginia group, and others, also have tried to use interferon to prevent colds. In a 1982 study of daily interferon use for three weeks, "we could show protection against rhinovirus colds," Hayden said. But the interferon users suffered side effects that were just like having a cold -- stuffy nose, dryness, blood-tinged mucus and rawness and irritation of the lining of the nose. Overall, they had more symptoms than those who did not get interferon. Smaller doses of interferon over long periods of time did not eliminate the side effects.
So the Virginia group decided to use interferon once a day for one week, only when someone else in the family actually had a cold.
The shorter time and lower doses prevented the cold from spreading, and there were fewer side effects. Five percent of the interferon spray users had some blood in their nasal mucus and 3 percent complained of dryness in the nose, said Hayden.
Even though the short-term use appears to work, Schering-Plough Corp. of Kenilworth, N.J., the company that produced the interferon used in the study, has declined to predict when it might be available or estimate how much each treatment may cost.
Despite problems of side effects and expense, it is unclear whether anyone other than those with chronic lung diseases -- such as asthma, bronchitis and emphysema -- who can become extremely ill from a simple cold, will use a prescription drug each time someone else in their family has a cold.
After all, since the hands spread most of the rhinoviruses among the family, stopping a cold may be as simple as washing your hands.