50 Fun Facts About Common Cold

Roughly how many virus strains are implicated in causing the common cold?

Well over 200 distinct virus strains can produce a cold, spread across several families, which is why a person can catch cold after cold without lasting immunity.

Which group of viruses causes the largest share of colds, up to 40 percent?

They have more than 100 known serotypes; the cause of 20 to 30 percent of colds remains unidentified.

How many colds does the average adult get per year?

Two to three colds a year is the adult average; the rate falls with age as immunity to more strains accumulates, and infections cluster in the colder months.

How soon after exposure can cold symptoms begin?

Within about 16 hours of exposure the first symptoms, usually a sore or scratchy throat, can appear; they typically peak two to four days after onset and resolve within seven to ten days.

What is the average duration of a cough caused by a cold?

18 days is the average length of a cold's cough, far longer than most people expect; in children it runs past 25 days in about one case in ten, and some develop a lingering post-viral cough.

What mainly produces the symptoms of a cold?

The body's own immune response, not viral damage, drives most cold symptoms: the virus barely harms the nasal lining, but inflammatory mediators it triggers cause the swelling, mucus and sneezing.

For how long can the commonest cold viruses survive on surfaces?

Over 18 hours is how long the commonest cold viruses can remain infectious on surfaces, so hands that touch a doorknob and then the eyes or nose are a major route of transmission.

What does the colour of nasal mucus, from clear to green, tell you?

Nothing about whether it is viral or bacterial: mucus turns yellow or green from an enzyme released by white blood cells drawn into the nose, a normal stage of any cold.

Which symptom is less likely in influenza than in a common cold?

A runny nose is typical of a cold but less common in influenza, which instead tends to bring sudden high fever, muscle aches and exhaustion; in adults, cough plus fever points towards flu.

Why is there no vaccine for the common cold?

The viruses are too many and mutate too fast for a single vaccine to cover them: hundreds of strains from several families cause colds, so immunity to one leaves the others untouched.

Which supplement may shorten a cold by up to a third if started within 24 hours?

Zinc lozenges or syrup begun within 24 hours of symptoms reduced cold length by up to a third in some trials, though reviews disagree on recommending it; nasal zinc gels were withdrawn after causing loss of smell.

What effect has regular vitamin C supplementation been shown to have on colds?

It may shorten them slightly but not prevent them: regular vitamin C cut cold duration by about 8 percent in adults and 14 percent in children in pooled trials, without reducing how many colds people caught.

What proportion of the benefit from cold remedies is attributed to the placebo effect?

A large part of it: trials show much of the relief from symptomatic cold treatments comes from the placebo effect, which is why rest, fluids and gargling warm salt water are reasonable conservative measures.

In 2009, Canada restricted over-the-counter cough and cold medicines for children up to what age?

Six and under was the cut-off Health Canada set in 2009, because trials showed no benefit from cough and cold medicines in young children and there were reports of serious side effects and overdoses.

What is the effect of antibiotics on the common cold?

None; they cause overall harm through side effects: antibiotics act only on bacteria, so against a viral cold they offer no benefit while bringing rashes, diarrhoea and resistance risks; they are reserved for secondary bacterial infections.

Which of these oral cold-remedy ingredients has solid evidence of easing a stuffy nose in adults?

Pseudoephedrine, taken by mouth, measurably reduces nasal congestion in adults; its rival phenylephrine, which replaced it on many open shelves, was judged ineffective orally by a 2023 FDA advisory panel.

Under what conditions is moderate exercise considered safe with a cold?

If symptoms are confined to the head, such as sneezing or a sore throat, light to moderate exercise is generally considered fine; fever, chest congestion, widespread aches or fatigue are signs to rest instead.

What is the estimated basic reproduction number of common cold viruses?

2 to 3 is the estimated basic reproduction number, meaning each infected person passes a cold to two or three others on average in a susceptible population; measles, by contrast, runs to 12 to 18.

In what proportion of children's colds does an ear infection develop as a complication?

About 30 percent of colds in young children are followed by a middle-ear infection, because their short eustachian tubes let the infection spread; sinusitis follows in about 8 percent.

Should a breastfeeding mother with a cold keep breastfeeding?

Yes, the virus is not passed in breast milk; the milk instead carries the mother's antibodies, and by the time she has symptoms the baby has already been exposed through the air and touch.

A cold outbreak at a British Antarctic base after 17 weeks of isolation was blamed on what?

Transmission from animals is considered highly unlikely.

Is there evidence that recirculated cabin air spreads colds on commercial flights?

No, but sitting close to others raises the risk: studies found no link between recirculated cabin air and colds, while proximity to a coughing passenger did matter; crowded settings like schools remain the classic amplifiers.

Which ancient text, written over 3,500 years ago, describes cold symptoms and treatments?

The Egyptian Ebers papyrus, a scroll of some 700 remedies copied around 1550 BC, includes remedies for nasal catarrh and cough, showing colds were familiar in ancient Egypt.

When did the name 'cold' come into use for the illness?

The 16th century is when English speakers began calling the illness a 'cold', because its chills and streaming nose resembled the effects of exposure to cold weather.

Near which English city was the Medical Research Council's Common Cold Unit based from 1946?

Salisbury, in Wiltshire, was the home of the Common Cold Unit, which occupied the Harvard Hospital at Harnham Down, a wartime gift from Harvard University and the American Red Cross.

How did the Common Cold Unit present a stay at its facility in adverts recruiting volunteers?

As an unusual holiday opportunity: adverts offered a free ten-day stay with country walks, and volunteers were kept in small isolated groups, barred from visiting residential areas, while being dosed with nasal drops.

How many scientific papers did the Common Cold Unit produce between 1946 and 1989?

1,006 scientific papers came out of the unit in 43 years, covering transmission, immunity and trials of remedies, before it closed in 1989 having found no cure.

Which family of viruses was first identified in nasal washes from a boy at the Common Cold Unit in 1960?

Coronaviruses were first recognised from strain B814, grown from the washings and reported in the BMJ in 1965; June Almeida's electron micrographs showed the crown-like halo that gave the family its name in 1968.

In which year was the rhinovirus discovered at the Common Cold Unit?

1956 marked the discovery of the rhinovirus, ten years after the unit opened; decades of volunteer trials followed, including 1970s work showing interferon given during incubation gave some protection, without yielding a practical treatment.

How did Walther Kruse show in 1914 that colds had a non-bacterial cause?

Filtered a colleague's diluted nasal secretions and dosed his staff: Kruse passed the mucus through a bacteria-stopping filter and put drops in the noses of twelve staff, four of whom developed colds.

At what temperature do the commonest cold viruses prefer to replicate?

33 °C, the temperature inside the nose, suits the commonest cold viruses better than the 37 °C of the body core, which is why they flourish in the upper airway rather than the lungs.

From which language does the 'rhino' in rhinovirus come, and what does it mean?

The virus is a single-stranded RNA enterovirus in the family Picornaviridae.

What is the medical term for a sneeze?

Sternutation is the medical term for sneezing, from Latin sternuere, 'to sneeze'; the other options are real terms too: singultus is a hiccup, eructation a burp and borborygmus a rumbling gut.

Is it really impossible to sneeze with your eyes open?

No, the eyelid reflex can be suppressed: the eyes close automatically as part of the sneeze, but people can keep them open with effort, and the eyes are in no danger of popping out.

Which inherited sneeze reflex, nicknamed ACHOO syndrome, affects roughly one person in four?

Sneezing triggered by sudden bright light, the photic sneeze reflex, affects an estimated 18 to 35 percent of people and runs in families; its tongue-in-cheek acronym ACHOO stands for autosomal dominant compulsive helio-ophthalmic outbursts.

What does the German response to a sneeze, 'Gesundheit', literally mean?

Health is the literal meaning of Gesundheit, from gesund, 'healthy'; the wish entered American English through German immigrants in the early 20th century, sitting alongside the older 'bless you'.

By what nickname is chicken soup known for its reputed powers against colds?

Jewish penicillin is the affectionate nickname, reflecting chicken soup's place in Ashkenazi home remedies; a 2000 University of Nebraska study found it could dampen neutrophil movement in the lab, hinting at a mild anti-inflammatory effect.

Which arthritis rub inspired Lunsford Richardson to formulate Vicks VapoRub?

Richardson worked in Selma, North Carolina; the rub must never be heated or added to hot water.

For what purpose was Kleenex first marketed in 1924?

Removing cold cream was the original pitch: Kleenex launched in 1924 as a disposable 'Kerchief' for wiping off make-up and cold cream, and only in 1930 did the company repitch it for blowing noses after customer letters.

Roughly how many doctor visits a year does the common cold cause in the United States?

75 to 100 million physician visits a year are attributed to colds in the United States, at a conservative cost of about $7.7 billion, plus $2.9 billion spent on over-the-counter remedies.

How many US school days are estimated to be missed each year because of colds?

22 to 189 million school days a year are lost to colds in the United States, by one widely cited estimate, and parents in turn miss about 126 million workdays caring for sick children.

Which antiviral showed promise against cold viruses but hit safety issues in oral form?

Pleconaril, a capsid-binding drug active against picornaviruses, shortened colds in trials but was refused approval in 2002 over drug interactions, including reduced effectiveness of oral contraceptives; an inhaled form was later studied.

How many colds a year does a young child typically catch?

Six to eight colds a year is typical for a young child, whose immune system has yet to meet most strains and who mixes closely with other children at nursery or school; the number falls through adulthood.

Roughly how many US workdays do employees miss each year because they have a cold?

150 million workdays a year are lost by US employees with colds, and the total cold-related work loss, including parents caring for sick children, tops $20 billion, about 40 percent of all US work time lost.

What share of Americans who see a doctor for a cold receive an antibiotic prescription?

More than one-third of Americans who see a doctor for a cold walk out with an antibiotic prescription, despite colds being viral; such needless prescribing is a major driver of antibiotic resistance.

Which two lifestyle factors are linked to a higher risk of infection after rhinovirus exposure?

Insufficient sleep and malnutrition both weaken immune defences: in one study, people sleeping under seven hours were about three times as likely to develop a cold after being given the virus as those sleeping eight or more.

How many recognised types of rhinovirus exist across its three species, A, B and C?

At least 165 types are recognised across rhinovirus species A, B and C; the C species, discovered only in 2006, could not be grown in standard cell culture, which is why it was missed for decades.

Roughly how big is a rhinovirus particle?

30 nanometres is the diameter of a rhinovirus particle, among the smallest of all viruses; influenza particles run 80 to 120 nanometres and smallpox virus about 300.

Which cough-medicine ingredient is restricted in some countries because of recreational misuse?

Dextromethorphan, the common 'DM' cough suppressant, produces dissociative effects at high doses, so recreational misuse has led some countries to restrict it to pharmacies or prescriptions and several US states to bar sales to minors.

What is the formal medical name for the common cold?

Acute nasopharyngitis, or acute viral rhinopharyngitis, is the clinical name for the common cold, reflecting inflammation of the nose and pharynx; bronchitis, sinusitis and laryngitis are distinct conditions that can follow a cold.