Colds and Flu

It can be hard to tell whether you have a cold or the flu as many of the symptoms are similar. Both are contagious viral infections that attack the respiratory tract.¹

Both a cold and flu may cause a runny nose, a sore throat, a cough, or a headache.² Colds, while uncomfortable, are usually milder than flu and generally do not result in serious health problems. Flu, however, tends to be more severe and sometimes develops into serious illness.¹

The differences are summed up as follows:^1.2

Your doctor can usually diagnose a cold or flu by asking about your symptoms and doing a physical examination. If they suspect you have another condition like COVID-19, you may need a nasal swab test (cotton swab rubbed inside the nose) or other tests.³

Colds and flu also get confused with allergic rhinitis (hay fever), which has some similar symptoms (sneezing, blocked or runny nose), but is not contagious.⁴ Allergies are triggered by allergens in the environment e.g. pollen or dust mites.⁴ Itchy, red or watery eyes are typical symptoms of allergic rhinitis.⁴

Colds are often called “the common cold” because they are such frequent infections: you will probably have more colds in your lifetime than any other illness.⁵

A cold is an infection of the nose, throat and often the sinuses (air cavities connected to the nose).⁵

More than 200 different viruses can cause colds. Although you can catch a cold any time of the year, it is more likely in winter, when people stay indoors and are in closer contact.⁵

Colds spread easily. Someone can spread a cold from a day or two before symptoms start, for up to two weeks. The virus must reach the mucous membranes of the nose, mouth or eyes to cause infection. You can catch a cold by:⁵

• Inhaling airborne droplets of fluid containing the cold virus, which enter the air when an infected person coughs or sneezes.
• Touching an object or surface contaminated by infected droplets and then touching your nose, mouth or eyes.

The common cold occurs more often in children as they have not been exposed to as many viruses as adults. In addition, children are in close contact with other children, and typically do not cover their coughs or sneezes or wash their hands before touching their faces.⁵

Symptoms may include:^2,5

• Sore throat
• Congested (blocked) or runny nose
• Sneezing
• Cough
• Hoarse voice
• Feeling tired
• Headache
• Low-grade fever

Colds usually clear up in 7-10 days.⁵

Consult your doctor without delay if you have a cold and:⁵

• Symptoms persist after 10 days
• Symptoms worsen and/or you develop a high fever
• Chest pain
• Ear pain
• Asthma flare-up or difficulty breathing

Most colds can be managed at home:

• Rest.⁵
• Drink plenty of fluids to keep your nose and throat moist. Avoid alcohol and caffeine, which have a drying effect.⁵
• Ask your pharmacist for advice to help relieve your symptoms.
• Consider Vitamin C intake – it contributes to immune function⁶

You can catch the flu all year round, but like the common cold, it is especially common in winter. In South Africa, flu season starts around mid-May. Flu viruses can change a little bit every year.^7,8

Who is at risk for flu and its complications?

Flu resulting in mild illness is most common in children of school-going age, between 5-15 years old.⁷ It can also cause serious illness that may require hospitalisation.⁸

Groups most at risk for flu-causing severe illness and complications include:⁷

• Children below the age of 5
• Adults aged 65 years or older
• Pregnant women
• People with chronic health conditions such as heart disease, lung disease (e.g. tuberculosis (TB), kidney, liver, blood or metabolic diseases (e.g. diabetes)), or weakened immunity.

Flu is caused by infection with the influenza virus. Like cold viruses, influenza spreads when you inhale airborne respiratory droplets or touch contaminated surfaces and then touch your nose, mouth or eyes.⁷

Symptoms may include:^7,8

• Sudden fever
• Tiredness or feeling run down
• Headache
• Muscle aches and other body pains
• Dry cough
• Sore throat
• Chills
• Runny or blocked nose
• Generally feeling unwell
• In children, symptoms may include vomiting or diarrhoea

Symptoms usually develop 1-4 days after becoming infected, and last for 2-7 days.⁷ Most people feel better within a week or two, but you may have a cough or runny nose which lasts for longer.^7,8

Milder cases of flu can be managed at home:^7,8

• Stay home and get plenty of rest
• Heat packs or hot water bottles can help with aching muscles
• Stay hydrated
• Ask your health care provider for advice to help relieve your symptoms

More severe cases may require prescription antiviral medications, ideally taken within 48 hours after symptoms start. Antiviral treatment may also be recommended early in the infection for people at risk of severe flu.⁷

Consult your doctor without delay if flu symptoms are present and:⁸

• You have an underlying condition that puts you at higher risk for severe illness (see above who is at risk for severe illness)
• There is no improvement after 7 to 10 days
• You have a fever lasting longer than 3 days
• You are pregnant
• Your symptoms are worsening. In case of severe symptoms, including fever over 40^oC, difficulty breathing, severe muscle pain, persistent dizziness or confusion, or a bluish tinge to skin, lips or nails, seek immediate medical attention.

The following measures may help protect you, your family and your community from the flu:⁸

• Wash hands often with soap and water. When you cannot wash your hands, use alcohol-based hand sanitiser.⁸
• Cover your nose and mouth when you sneeze or cough. Sneeze and cough into tissues rather than your bare hands. If you are caught without tissues, cough or sneeze into your elbow.⁸
• Avoid unnecessary contact with people while you are infectious.⁸
• Avoid touching your face, eyes, nose and mouth.⁸
• Do not share items if you are infectious e.g. eating utensils.⁸
• Speak to your healthcare provider about the annual flu vaccine – a different vaccine is offered every year, as the flu virus is constantly changing. Anyone wishing to lower their risk of getting flu can get vaccinated, but it is especially recommended for people at high risk of severe illness.⁷