What is common cold

Common cold is a very common viral infection of your nose and throat (upper respiratory tract). Common cold symptoms include coughing, fever, sore throat, sneezing, blocked or runny nose and general congestion. Common cold is usually harmless, although it might not feel that way. Common colds are caused by about 200 different viruses and there is no vaccine for a common cold. The most common one is the rhinovirus, followed by the corona virus and the respiratory syncytial virus (RSV). Other viruses that can cause colds include human parainfluenza viruses and human metapneumovirus. The large number of viruses capable of causing common colds explains why you repeatedly catch colds.

Children younger than six are at greatest risk of colds, but healthy adults can also expect to get common cold. Children may get 5-10 colds a year, while adults may get 2-4 colds each year.

Most people recover from a common cold in a week or 10 days. Symptoms might last longer in people who smoke. If symptoms don’t improve, see your doctor.

How long is the common cold contagious?

Symptoms are the first sign of common cold infection and they typically begin 24 hours after the common cold germs have entered a person’s respiratory tract. But you are contagious and can pass the virus onto someone else as soon as you are infected. That means every time somebody gets a common cold, they are contagious for about a day before they start to feel sick and realize they might pass their sickness on to someone else. That’s why it’s important to pay attention to common cold and flu prevention measures like hand washing at all times, not just when someone in the house or office is sick.

Common colds and flus remain contagious for about a week after infection occurs. The potential to transmit a common cold to someone reduces after the second or third day of infection, but it is still possible to infect another person for up to seven days. If you have the flu, the risk of infecting someone else reduces after the fifth day.

How to avoid spreading a common cold

Common cold are caused by viruses and easily spread to other people. You’re infectious until all your symptoms have gone. This usually takes a week or two.

Common colds are spread by viruses from coughs and sneezes which can live on hands and surfaces for 24 hours.

To reduce the risk of spreading a cold:

• wash your hands often with warm water and soap
• use tissues to trap germs when you cough or sneeze
• bin used tissues as quickly as possible.

Common cold complications

• Acute ear infection (otitis media). This occurs when bacteria or viruses enter the space behind the eardrum. Typical signs and symptoms include earaches and, in some cases, a green or yellow discharge from the nose or the return of a fever following a common cold.
• Asthma. A cold can trigger an asthma attack.
• Acute sinusitis. In adults or children, a common cold that doesn’t resolve can lead to inflammation and infection of the sinuses (sinusitis).
• Other secondary infections. These include strep throat (streptococcal pharyngitis), pneumonia, and croup or bronchiolitis in children. These infections need to be treated by a doctor.

Some complications that may develop in high risk individuals include ear infections, pneumococcal pneumonia, sinusitis and bronchitis. Pneumonia is the most common and serious complication. It can sometimes lead to death for older people or people with chronic illnesses. A generally healthy person is less likely to catch a cold and if they do catch one, they will be better able to fight it.

You may be more at risk of serious complications, such as pneumonia and bronchitis if you:

• are over 65
• have serious heart or chest complaints, including asthma
• have serious kidney disease or liver disease
• have diabetes
• have lowered immunity
• had a stroke or transient ischemic attack (TIA).

Common cold vs flu

Common cold and flu (influenza) symptoms are similar, but flu (influenza) tends to be more severe. Both common colds and flus are highly contagious. They can be passed from person to person by inhaling infected air droplets created from sneezing or coughing, or by hand contact or contact with surfaces that may have been touched by an infected individual (e.g. door knobs, pens and phones).

Colds and flus both infect organs in the respiratory tract including the nose and throat. Both also come with unpleasant symptoms like fever, cough and blocked nose. But the common cold and influenza differ in their severity, and the pattern of symptoms they produce.

The common cold tends to be less severe and is typically associated with runny nose, sneezing and sore throat. These symptoms are less common with influenza, a more serious infection which usually produces a dry cough, body ache and headaches.

Table 1. Telling the difference between common cold and flu

How to tell the difference between common cold or flu?

Because colds and flus have many common symptoms, distinguishing between them can be difficult. The most accurate way is through diagnostic testing in the first few days of illness. However, the severity and type of symptoms are good indicators which can differentiate between colds and flus. Flus are generally more severe and typically involve systemic symptoms like body ache and fever.

Symptoms of the common cold generally improve without treatment. Influenza usually resolves with simple medicines like painkillers to treat symptoms and does not generally require prescription medicines.

However, sometimes influenza symptoms persist and the infection causes serious complications which require treatment, including pneumonia. So it is important to be able to identify whether you have the common cold or influenza.

Common cold

Colds typically begin slowly with a feeling of tiredness, a runny nose and sneezing. The ears are often affected and feel blocked or as though they are popping. Muscle aches, sore throat, headaches and a mild fever may also be experienced. The severity of symptoms peaks 2-3 days after infection and lasts 7-10 days. However, some symptoms may persist for several weeks.

The most common way for people to become infected with cold viruses is by touching the eyes and nose with contaminated hands. Rhinoviruses can survive on hands and surfaces for several hours. The other route of infection is by inhaling aerosols containing infected virus particles released after an infected individual has sneezed or coughed.

Influenza

A flu is a more severe infection. It develops suddenly and is associated with:

• Headache;
• Sudden fever – a temperature of 38 °C (100.4 °F) or above;
• Chills and sweats;
• Dry, chesty cough;
• Loss of appetite;
• Body aches;
• General feeling of weakness;
• Feeling tired or exhausted;
• Diarrhea or tummy pain;
• Nausea and being sick;
• Difficulty sleeping.

Congestion, sore throat and eye pain may also be experienced. The symptoms are similar for children, but they can also get pain in their ear, diarrhea and vomiting and appear less active. The flu lasts much longer than a cold. In some cases, it may lead to serious complications such as pneumonia.

How to prevent flu

Three different types of influenza viruses infect humans – types A, B and C. This virus is able to mutate and change its structure, giving rise to different strains every year. The body does not have any immunity to the new strain, so you can be repeatedly infected. This is why you need to get a new flu vaccine every year. Only influenza A and B cause major outbreaks and severe disease.

There is a vaccine available for the flu and it’s recommended ‘at risk’ people, such as the elderly or those with chronic illnesses have an annual flu vaccination. Flu viruses circulating in the community continually change, and immunity from the vaccine doesn’t last a long time so that’s why yearly vaccination is recommended. The flu vaccine reduces the risk of catching flu, as well as spreading it to others.

It’s more effective to get the vaccine before the start of the flu season.

Good hygiene is one of the most important ways to help prevent colds and flu.

Other ways to help prevent flu can include antiviral medicines, although these are only recommended for preventing flu if you have been exposed to the flu in the previous 48 hours.

Flu Vaccination

Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices (ACIP)—United States, 2017-18 ¹

• Routine annual influenza vaccination is recommended for all persons aged ≥6 months who do not have contraindications.
• Emphasis should be placed on vaccination of high-risk groups and their contacts and caregivers (no hierarchy is implied by order of listing):
  • Children aged 6-59 months;
  • Adults aged ≥50 years;
  • Persons with chronic pulmonary (including asthma), cardiovascular (except isolated hypertension), renal, hepatic, neurologic, hematologic, or metabolic disorders (including diabetes mellitus);
  • Persons who are immunocompromised due to any cause, (including medications or HIV infection);
  • Women who are or will be pregnant during the influenza season;
  • Children and adolescents (aged 6 months through 18 years) receiving aspirin- or salicylate-containing medications and who might be at risk for Reye syndrome;
  • Residents of nursing homes and other long-term care facilities;
  • American Indians/Alaska Natives;
  • Persons who are extremely obese (BMI ≥40); and
• Caregivers and contacts of those at risk:
  • Health care personnel in inpatient and outpatient care settings, medical emergency-response workers, employees of nursing home and long-term care facilities who have contact with patients or residents, and students in these professions who will have contact with patients;
  • Household contacts and caregivers of children aged ≤59 months (i.e., <5 years), particularly contacts of children aged <6 months, and adults aged ≥50 years; and
  • Household contacts and caregivers of persons who are in one of the high-risk categories listed.

How to treat flu yourself

To help you get better more quickly:

• rest and sleep
• keep warm
• take paracetamol or ibuprofen to lower your temperature and treat aches and pains
• drink plenty of water to avoid dehydration (your pee should be light yellow or clear)

Doctor don’t recommend antibiotics for flu because antibiotics only work for bacterial infections so they won’t work for colds and flu which are caused by viruses.

Common cold causes

Although many types of viruses can cause a common cold, rhinoviruses are the most common culprit.

A cold virus enters your body through your mouth, eyes or nose. The virus can spread through droplets in the air when someone who is sick coughs, sneezes or talks.

It also spreads by hand-to-hand contact with someone who has a cold or by sharing contaminated objects, such as utensils, towels, toys or telephones. If you touch your eyes, nose or mouth after such contact or exposure, you’re likely to catch a cold.

Risk factors for common cold

These factors can increase your chances of getting a cold:

• Age. Children younger than six are at greatest risk of colds, especially if they spend time in child-care settings.
• Weakened immune system. Having a chronic illness or otherwise weakened immune system increases your risk.
• Time of year. Both children and adults are more susceptible to colds in fall and winter, but you can get a cold any time.
• Smoking. You’re more likely to catch a cold and to have more severe colds if you smoke.
• Exposure. If you’re around many people, such as at school or on an airplane, you’re likely to be exposed to viruses that cause colds.

How to prevent catching a cold

A person with a common cold can start spreading it from a few days before their symptoms begin until the symptoms have finished. The best ways to avoid catching a cold are:

• Washing your hands with warm water and soap. Viruses that cause colds can live on your hands, and regular handwashing can help protect you from getting sick. Teach your children the importance of hand-washing. If soap and water aren’t available, use an alcohol-based hand sanitizer.
• Disinfect your stuff. Clean kitchen and bathroom countertops with disinfectant, especially when someone in your family has a cold. Wash children’s toys periodically.
• Not sharing towels or household items (like drinking cups) with someone who has a common cold.
• Use tissues. Sneeze and cough into tissues. Discard used tissues right away, then wash your hands carefully. Teach children to sneeze or cough into the bend of their elbow when they don’t have a tissue. That way they cover their mouths without using their hands.
• Not touching your eyes or nose in case you’ve come into contact with the virus – it can infect the body this way.
• Take care of yourself. Eating well, getting exercise and enough sleep, and managing stress might help you keep colds at bay.
• Steer clear of colds or people who are sick. Avoid close contact with anyone who has a cold. Sick people can spread viruses that cause the common cold through close contact with others.
• Choose your child care center wisely. Look for a child care setting with good hygiene practices and clear policies about keeping sick children at home.

Sometimes it is difficult to identify sick people, as people who are infectious may not have any symptoms in the early stages of their illness. Try to avoid people who you know have a cold or flu, and stay away from crowded areas during flu season to reduce your chance of infection. This is particularly important for babies in the first few months of life.

The flu vaccine helps prevent the flu but not common colds.

Healthy eating

Eating a balanced diet provides your body with the nutrients and vitamins it needs to help the immune system fight infection. Eat foods containing phytochemicals such as dark green, red and yellow fruit and vegetables. Eating a colourful diet (yellow, orange, purple, red and green vegetables) is a good way to ensure your diet includes all the micronutrients your immune system needs.

Foods containing healthy oils like salmon, kefir, tuna, flaxseeds and walnuts are also great for the immune system, as are Vitamin C rich food like oranges and tomatoes. Vitamin E and Selenium are two other immune boosting micronutrients you should include in your diet. Broccoli, brussel sprouts and almonds are all good sources of vitamin E and meat and poultry are rich in selenium. Eating a tub of yogurt daily can reduce the chance of catching a cold by 25%.

Other healthy eating habits which can boost the immune system include:

• Eat a healthy breakfast everyday;
• Grill, steam or bake foods instead of frying;
• Eat sugary foods in moderation;
• Limit alcohol consumption;
• Eat plenty of fruits and vegetables.

If you need to improve your diet, try to make changes gradually, for example by adding one healthy habit per day.

Rest

Getting plenty of sleep also helps boost the functioning of your immune system. You should aim to get at least 7-8 hours of sleep a night. People who sleep less than 7 hours a night are nearly 3 times more likely to catch a cold than those getting more than 8 hours a night. Just resting and relaxing is also important.

Reduce stress

People who are under stress tend to have weakened immune systems, so are more likely to get sick and experience more severe symptoms.

People who are more sociable are less likely to get sick. Researchers believe this is because people who have more social contacts and support are less likely to feel stressed than people who keep to themselves. So if you are run down or stressed, try to incorporate some relaxation techniques into your life. If you remain relaxed, your immune system produces more of the chemicals needed to fight infection (interleukins).

Stop smoking

Smokers are more prone to respiratory illness than non-smokers, and experience more severe and frequent colds. This is because cigarette smoke dries out nasal passages and paralyses the hairs that line the mucous membranes, which normally act to sweep viruses out of the nasal passages. Non-smokers should take care to avoid second-hand smoke.

Exercise regularly

Regular exercise, particularly cardiovascular exercise, helps keeps you fit and gives your immune system a boost, enabling it to function more effectively. Exercise can increase the number of virus-killing cells in your body. It may not prevent all infections, but it can speed up recovery and reduce the intensity of symptoms. Exercise also helps you distress which is an important part of staying healthy.

Regulate humidity

Other ways to avoid catching a cold are to ensure your house is not overheated, and to increase the humidity by using cool mist humidifiers or vaporizers. The low humidity created by heating dries out the mucous membranes of the nasal passages, making you more vulnerable to infection. Low humidity also provides an environment that encourages viruses to survive and thrive. Make sure you go out and get fresh air to counteract the drying effects of indoor heating.

How to Protect Others

If you have a cold, you should follow these tips to prevent spreading it to other people:

• Stay at home while you are sick
• Avoid close contact with others, such as hugging, kissing, or shaking hands
• Move away from people before coughing or sneezing
• Cough and sneeze into a tissue then throw it away, or cough and sneeze into your upper shirt sleeve, completely covering your mouth and nose
• Wash your hands after coughing, sneezing, or blowing your nose
• Disinfect frequently touched surfaces, and objects such as toys and doorknobs

There is no vaccine to protect you against the common cold.

Practice good cough and sneeze etiquette: always cough and sneeze into a tissue or your upper shirt sleeve, completely covering your mouth and nose.

Common cold symptoms

Symptoms of a common cold usually appear one to three days after exposure to a cold-causing virus.

Common cold signs and symptoms come on gradually and can include:

• blocked or runny nose
• sore throat
• mild headache
• slight body aches or muscle aches
• coughs
• sneezing
• a high temperature (more than 38 °C [100.4 °F] in adults, 37.5 °C [99.5 °F] in children)
• pressure in your ears and face
• generally feeling unwell (malaise)
• loss of taste and smell

The symptoms are the same in adults and children. Sometimes, symptoms last longer in children.

The discharge from your nose may become thicker and yellow or green in color as a common cold runs its course. This isn’t an indication of a bacterial infection.

Common cold diagnosis

Most people with a common cold can be diagnosed by their signs and symptoms. If your doctor suspects you have a bacterial infection or other condition, he or she may order a chest X-ray or other tests to exclude other causes of your symptoms.

Common cold treatment

There’s no cure for the common cold. Antibiotics are of no use against cold viruses and shouldn’t be used unless there’s a bacterial infection. Treatment is directed at relieving signs and symptoms.

To help you get better more quickly:

• rest and sleep
• keep warm
• drink plenty of water (fruit juice or squash mixed with water is ok) to avoid dehydration
• gargle salt water to soothe a sore throat

You can buy cough and cold medicines from pharmacies or supermarkets. A pharmacist can advise you on the best medicine.

You can:

• relieve a blocked nose with decongestant sprays or tablets
• ease aches or lower a temperature with painkillers like paracetamol or ibuprofen

Be careful not to use cough and cold medicines if you’re taking acetaminophen (Tylenol, others) and ibuprofen tablets as it’s easy to take more than the recommended dose. Use acetaminophen for the shortest time possible and follow label directions to avoid side effects.

Some are not suitable for children, babies and pregnant women. Use caution when giving aspirin to children or teenagers. Children and teenagers recovering from chickenpox or flu-like symptoms should never take aspirin. This is because aspirin has been linked to Reye’s syndrome, a rare but potentially life-threatening condition, in such children.

Consider giving your child over-the-counter (OTC) pain medications designed for infants or children. These include acetaminophen (Tylenol, Infant’s Feverall, others) or ibuprofen (Pediatric Advil, Motrin Infant, others) to ease symptoms.

There’s little evidence that supplements (such as vitamin C, zinc, echinacea or garlic) prevent colds or speed up recovery.

Decongestant nasal sprays. Adults can use decongestant drops or sprays for up to five days. Prolonged use can cause rebound symptoms. Children younger than six shouldn’t use decongestant drops or sprays.

Cough syrups. The Food and Drug Administration (FDA) and the American Academy of Pediatrics strongly recommends against giving OTC cough and cold medicines to children younger than age 4. There’s no good evidence that these remedies are beneficial and safe for children.

If you give cough or cold medicines to an older child, follow the label directions. Don’t give your child two medicines with the same active ingredient, such as an antihistamine, decongestant or pain reliever. Too much of a single ingredient could lead to an accidental overdose.

Antibiotics

Doctors don’t recommend antibiotics for colds because they won’t relieve your symptoms or speed up your recovery.

Antibiotics are only effective against bacterial infections and colds are caused by viruses.

Home remedies for common cold

To make yourself as comfortable as possible when you have a cold, try:

• Drinking plenty of fluids. Water, juice, clear broth or warm lemon water are good choices. Avoid caffeine and alcohol, which can dehydrate you.
• Eating chicken soup. Chicken soup and other warm fluids can be soothing and can loosen congestion.
• Resting. If possible, stay home from work or school if you have a fever or a bad cough or are drowsy after taking medications. This will give you a chance to rest as well as reduce the chances that you’ll infect others.
• Adjusting your room’s temperature and humidity. Keep your room warm, but not overheated. If the air is dry, a cool-mist humidifier or vaporizer can moisten the air and help ease congestion and coughing. Keep the humidifier clean to prevent the growth of bacteria and molds.
• Soothing your throat. A saltwater gargle — 1/4 to 1/2 teaspoon salt dissolved in a 4-ounce to 8-ounce glass of warm water — can temporarily relieve a sore or scratchy throat.
• Using saline nasal drops. To help relieve nasal congestion, try saline nasal drops. You can buy these drops over-the-counter, and they can help relieve symptoms, even in children. In infants, gently suction the nostrils with a bulb syringe (insert the bulb syringe about 1/4 to 1/2 inch, or about 6 to 12 millimeters) after applying saline drops.

Alternative medicine

In spite of ongoing studies, the scientific jury is still out on common alternative cold remedies such as vitamin C and echinacea. Here’s an update on some popular choices:

• Vitamin C. It appears that for the most part taking vitamin C won’t help the average person prevent colds.
• Echinacea. Studies on the effectiveness of echinacea at preventing or shortening colds are mixed. However, if your immune system is healthy, you’re not taking prescription medications and you’re not allergic to echinacea, using echinacea supplements is unlikely to cause harm.
• Zinc. The cold-fighting reputation of zinc has had its ups and downs. That’s because many zinc studies — both those that find the mineral beneficial and those that do not — are flawed. In studies with positive results, zinc seemed most effective taken within 24 hours of the onset of symptoms. Zinc side effects include a bad taste and nausea. Talk to your doctor before taking a zinc supplement. Intranasal zinc might cause permanent damage to the sense of smell. In June 2009, the FDA issued a warning against using three zinc-containing nasal cold remedies because they had been associated with a long-lasting or permanent loss of smell (anosmia).

1. 2017-18 Summary of Recommendations. https://www.cdc.gov/flu/professionals/acip/2017-18summary.htm[↩]