What is common cold or flu?

Common cold is generally used to describe an acute upper respiratory tract infection, characterized by running nose and mild cough. Influenza (Flu) is also an upper respiratory infection but has more generalized symptoms than the common cold.

What are the causes?

There are more than 200 different types of viruses which can cause colds and flu. The infections are predominantly transmitted by:

• Airborne: inhaling large particles of respiratory secretions in the air or small infectious particles suspended in the air for long periods of time; or
• Direct contact: touching infectious respiratory secretions on skin and on environmental surfaces and then touching the eyes or nose.

Fatigue and exposure to cold outdoor air alone do not lead to common cold.

The following people are more susceptible to be infected:

• Young children in day care centres.
• Frail aged residing in nursing homes or other long term facilities.
• People with compromised immune system.

What are the signs and symptoms of common cold or flu?

The most common signs and symptoms are:

• Sneezing, blocked or running nose.
• Sore throat.
• Cough or hoarseness.
• Headache.
• Sudden onset of fever for 2 to 3 days (children).

For flu, the fever is usually higher with sporadic chills and accompanied by fatigue, sweating, muscle or joint pain.

The illnesses are usually self-limiting. Since colds/flu are caused by viruses, antibiotics are usually unnecessary unless there is suspicion of secondary bacterial infection. Symptomatic treatment such as antihistamines cannot kill the viruses but may help to relieve the discomfort.

There are several things you can do to try to get well faster and to relieve your symptoms:

• Drink plenty of water will replace fluid loss and help loosen secretions.
• Inhale warm steam will increase mucous flow.
• Take nutritious and easily digested food.
• Take adequate rest.
• Gargle three or more times a day with 1/2-tablespoon salt in a glass of warm water.

It is important to note that many diseases may start out with similar symptoms as colds or flu. If any of the following symptoms persist, you should go to see a doctor:

• Fever of 100.5^oF (or 38.1^oC) or higher.
• A severe sore throat for longer than 3-4 days.
• Yellowish-green mucous from nasal passages or lungs.
• Earache.
• Difficulty in breathing.

Is there anything I can do to prevent colds/flu?

• The best way to prevent colds/flu is to build up good body resistance. This can be achieved by adopting a healthy lifestyle: a balanced diet, enough rest, regular exercise, avoid too much stress and no smoking.
• Hand washing after contact with infectious secretion is the simplest and most effective way to keep you from catching colds.
• Since colds are spread through the air, keep good ventilation of your environment. Avoid crowded places when you are feeling unwell.
• Influenza vaccination can help to reduce complications and deaths due to influenza especially among the elderly and patients with chronic cardiac or respiratory diseases. To keep the effectiveness, the vaccine has to be repeated yearly. If you have any queries, please consult your family doctor.