Every fall, as the weather gets colder and nighttime stretches longer, people brace for a season of sore throats, sneezing, and runny noses: the symptoms of the common cold.
A vaccine for the cold has eluded scientists for decades, leaving doctors with little prevention advice for patients other than to wash their hands, keep their hands off their faces, and avoid people who are sick. That final piece of advice is particularly difficult to follow during cold weather, when people are spending more time in close quarters with germs floating through the air and lingering on surfaces.
As a result, there are about 1 billion cases of the cold happen in the United States every year, with adults getting sick two to three times annually and children getting sick more often. A study from 2002 found the common cold costs the U.S. $25 billion annually in lost productivity as adults take sick days, and parents who work outside the home have to call out to care for sniffling children.
For scientists, the hardest part of finding a vaccine for the cold is that they are dealing with different types of viruses. More than 200 strains of viruses that cause the cold, and 160 of these are rhinoviruses.
A vaccine that fights off one strain of virus won’t work against another, and merely putting all different kinds of vaccines into one shot would make for a massive, unworkable vial of liquid. Moreover, viruses mutate over time.
“Making vaccines against many viruses is scientifically, we can say, impossible,” said Dr. William Schaffner, an infectious disease expert at Vanderbilt University School of Medicine in Nashville, Tennessee.
Other vaccines that fight viruses, such as polio and smallpox, don’t have to take on so many versions. Even the flu has only about three strains that circulate each season.
“The easy vaccines to be made have been made,” Schaffner said.
Schaffner does think a vaccine for the common cold is possible once scientists can figure out how to protect against a whole “family of viruses” that have traits in common, such as the rhinovirus.
But there are still monetary and practical considerations. Since the cold goes away in only a few days, any vaccine the Food and Drug Administration would approve would require little to no side effects. For a lot of drugmakers, the risk isn’t worth the investment.
“Common cold is seen as a nuisance rather than life-threatening, so there is less emphasis or need placed on developing a vaccine,” said Gary McLean of Imperial College London, who is waiting on funding to test his cold vaccine. McLean thinks experiments will take as long as a decade.
“We have learned that this is a slow and toilsome process,” he said.
What’s motivating some scientists to search for a vaccine is the severity of the cold for certain people. While it goes away after a few days for most, the common cold can be life-threatening for people who already have breathing problems. It triggers asthma attacks and flare-ups for people with chronic obstructive pulmonary disease, or COPD, which often hits seniors.
“It might well be that it would be a reasonable thing not to recommend the vaccine to everyone, but only to those people who could get very sick and maybe to their family members, so they don’t bring that virus home with them,” Schaffner said. “That might be a sufficient population and reason for insurers to cover it for those people.”
Under a government grant, researchers at the University of Wisconsin School of Medicine and Public Health are studying an association between children wheezing when they get the cold and the onset of asthma. They hope to see whether getting a vaccine against rhinovirus would help reduce the number of people with asthma, said Dr. James Gern, who is leading the research.
“They might be causing them,” Gern said of the rhinovirus link to asthma. “We haven’t proved that yet, but they are certainly a very good marker” of those likely to develop asthma, he said.
The next step, he said, will be to see whether all the strains of rhinovirus are causing severe problems or just some of them and to find out which kinds of people are the most at risk for developing serious conditions. That would help to narrow down the targets for a vaccine.
But a vaccine is not the only missing element of cold medicine-there’s also no cure. Doctors typically advise patients to rest and drink a lot of water, and people often buy decongestants over the counter or take Tylenol for a headache. Schaffner thinks that even more than a vaccine, a cure sold over the counter to make cold symptoms go away quickly would have a considerable market.
“Everyone wants to get better faster,” he said.
