Some people get back-to-back colds, infected by a new virus
March 24, 2014 7:02 p.m. ET
Rhinoviruses are the main cause of the common cold.
Science Picture Co./Corbis
About a month ago Sharon Gilbert was hit with a runny nose, sore throat and a cough. The whole snotty works.
A
few weeks later she thought she had recovered. Then her husband Derek
got sick, and bam. "Suddenly I started getting all the symptoms [again]
and it was worse," said Ms. Gilbert, a 61-year-old writer in Charleston,
Ill.
In the winter that seems to have
no end in many parts of the country, people like Ms. Gilbert have been
plagued with the seemingly everlasting cold.
That's
partly because the common cold can last longer than many people
think—up to two weeks for the principal symptoms and perhaps weeks more
for a cough that lingers even after the virus has been cleared away.
There's also the possibility of secondary infections such as bacterial
sinusitis.
And some patients might get
back-to-back colds, doctors say. It isn't likely people will be
reinfected with the same virus because the body builds some immunity to
it. But people can pick up another of the more than 200 known viruses
that can cause the common cold, some of which are worse than others.
The Cold Facts
- Adults on average get two to five colds a year, mostly between September and May. Young children can get as many as seven to 10 colds.
- More than 200 different viruses cause colds, and scientists continue to discover new ones.
- Colds are most contagious about two days before symptoms start and in the early stages of illness.
- The average cold lasts two to 14 days. Coughs can linger up to six weeks.
- Exercise, reducing stress, getting good sleep and hand hygiene can help prevent getting a cold.
"When you hear people who have the
cold that 'won't go away,' those are typically back-to-back infections
of which we see a lot of in the cold weather when people are cohorting
together," said Darilyn Moyer, a physician at Temple University Hospital
and chairwoman-elect of the American College of Physicians Board of
Governors.
Influenza may get all the
attention, but the common cold is the leading cause of doctor visits,
according to the National Institutes of Health. Each year, people in the
U.S. get about one billion colds, and 22 million school days are lost
to the stubborn viruses.
Experts say
adults on average get two to five colds a year; school children can get
as many as seven to 10. The elderly tend to get infected less because
they've built up immunity to many viruses. And adults who live or work
with young children come down with more colds.
Don't
I know it. For more than a month now my family seems to be playing a
game of pass-the-nasty-cold. My husband had a cold and lingering cough
for weeks, which we suspect he gave to our infant. Finally I succumbed.
We
blamed the purveyor of all germs, our kindergartner. Just as we were
all recovering, the infant started day care and brought home a virus and
we're all on round two of apparently a different cold.
Experts
say it's possible that the carrier of germs—in this case our
kindergartner—can infect others without having symptoms himself.
"At
any given moment if we were to swab you…we'd probably come up with five
different rhinoviruses sitting in your nose but you're not sick," said
Ann Palmenberg, a researcher at the Institute of Molecular Virology at
the University of Wisconsin-Madison. Rhinovirus is the most common viral
cause of the common cold, accounting for 30% to 50% of adult colds, and
there are more than 150 strains of it.
To
get infected, the so-called ICAM receptors, which the rhinovirus
attaches to in order to enter the nasal cells, need to be open, Dr.
Palmenberg said.
"Rhinos are out there
all the time, it's just a question of when you are susceptible," she
said. Factors such as stress, lack of sleep and people's overall health
can make them more likely to get infected. More than 150 strains or
genotypes of the rhinovirus have been identified and researchers believe
there are probably many more.
Rhinovirus
replicates best in the relatively lower body temperatures of the upper
respiratory area, such as the nasal passages, sinuses and throat.
Other
viruses, such as the less-common adenovirus, can replicate and attach
to receptors in the upper and lower respiratory tracts, causing a more
serious illness.
Other viruses—including
the coronavirus, respiratory syncytial virus and enterovirus—have also
been identified as causing cold symptoms. "The most confounding thing of
all is that we still haven't identified the cause of 20% to 30% of
adult common colds," said Anthony Fauci, director of the National
Institute of Allergy and Infectious Diseases, part of the National
Institutes of Health.
Sometimes a cold
that never seems to end could be a sign of something more serious. A
cold may result in a sinus infection, bronchitis or pneumonia. And cold
symptoms are at times confused with seasonal allergies.
A
usually dry cough that lingers after a cold is typically due to
bronchial hyperreactivity or tracheal inflammation, doctors say. "After
you go through an infection in your respiratory system, you can almost
have a transient form of asthma where your bronchial tubes are very
highly reactive and very irritated and inflamed," said Dr. Moyer, of
Temple University Hospital.
A review of
various studies, published last year in the journal Annals of Family
Medicine, found that coughs on average last about 18 days. The report
also said a survey of nearly 500 people found that most participants
expected a cough should disappear in about a week and believed
antibiotics from their doctor would help them. (A big no-no!)
Some
experts believe having one cold virus and a weakened immune system
could make catching another virus easier. Because the epithelial linings
in the nose are weakened when you have a cold, the broken down
mucus-membrane barrier may be more prone to picking up another virus.
But
others suggest that proteins such as interferons, which are secreted
during a cold to help fight the virus, may also boost resistance to
getting infected by a second virus, according to Dr. Fauci, of the NIH.
What
can a person do to prevent or shorten a cold? Nearly everyone knows
someone who swears by taking echinacea or zinc or downing packs of
vitamin C.
But doctors say the evidence
isn't conclusive that any of these remedies helps. Some research
indicates that exercise and meditation could help prevent colds.
The
good news is spring is here, at least officially, so the worst of the
winter cold season should be over. Come summer, however, a new batch of
viruses emerge and you might find yourself saying hello to the pesky
summer cold.
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