Influenza (Flu)

A cold is caused by one of several viruses that infect the upper part of the respiratory system, resulting in a runny nose, sore throat, or clogged feeling (upper respiratory tract). Although a cold can be debilitating, it is usually self-limiting in most people. This indicates that the body fights the illness and heals itself without the need for medical intervention.

Influenza, sometimes known as the flu, has symptoms that are similar to a cold but is a more serious condition. Flu can be harmful to persons who are frail or have a weaker immune system, even though it is usually self-limiting in most people. In general, there are two influenza peaks in Hong Kong: one in February and the other in July. However, this might be impacted by imported flu cases from other countries.

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Causes of Influenza

Flu viruses are passed from person to person through droplets in the air from sneezing or coughing, or by touching infected surfaces and then spreading the virus from the hands to the mouth. Flu viruses can be transmitted by handshakes or touching a door handle. Infected people can transfer the viruses for up to four days after the symptoms appear, starting two days before the illness. Flus can strike at any time of year, but they are more common in the winter.

People who live in residential or nursing homes, as well as those who have the following illnesses, are at risk:

  • Asthma
  • Chronic chest problems such as chronic bronchitis and emphysema
  • Diabetes
  • Heart disease
  • Kidney diseases and kidney failure
  • People with reduced immunity, such as people with HIV or people who have had their spleen removed

Symptoms of Influenza

Flu symptoms resemble that of colds, but with more severe muscular aches and weariness that can remain for several weeks after the sickness has passed. Flu might seem like a severe cold to most healthy individuals. Young children, the elderly, and those with certain chronic medical issues, on the other hand, are at risk of severe complications. The majority of them are caused by a secondary bacterial infection of the lungs (pneumonia) or the ears, nose, and throat (ENT). Fits, sometimes known as febrile convulsions, can occur in kids under the age of 6 due to a high body temperature.

If you experience the following symptoms while suffering from a cold, you should see a doctor right away:

  • Severe vomiting or diarrhea
  • Earache
  • Difficulty breathing
  • Skin rash
  • Uncontrollable cough
  • Cough with green sputum – phlegm
  • Extreme lethargy or drowsiness

Treatment of Influenza

Influenza have no known cure. Antibiotics, while effective against bacteria, are ineffective against viruses. Home treatment, on the other hand, can help to ease symptoms and ensure a quick recovery.

Home treatment

  • Drink a lot of fluids to prevent dehydration.
  • Avoid smoking.
  • Use decongestants such as pseudoephedrine to clear congestions. Ask your doctor for advice on products that contain a decongestant.
  • Use steam inhalations with menthol or eucalyptus, or herbal products such as chamomile.
  • Eat a balanced diet with plenty of fruit and vegetables.
  • Rest. Avoid strenuous exercise, as this can increase the chance of catching a secondary bacterial infection. 


Apart from the above-mentioned home care, no specific medical treatment is required for those in general good health, except for the elderly. Prescription-only medicines may be necessary for vulnerable individuals if complications or spread are a concern.

Adults can use paracetamol, aspirin, or ibuprofen to relieve fever and pain. Always read the instructions carefully and adhere to the recommended daily doses. It’s possible to accidentally go over these limits by taking many products (tablets, capsules, a hot lemon drink, etc.) that contain the same active component, such as paracetamol. Aspirin can be harmful to children under the age of 12. (in rare cases, it can cause Reyes syndrome).

Prevention of Influenza

  • Isolating people with flu to prevent it from spreading to other people if possible.
  • Regular hand washing and immediate disposal of tissues.
  • Maintain a healthy lifestyle with a balanced diet rich in fruit and vegetables, and regular (preferably daily) physical activity.
  • Do not smoke.

Getting a flu vaccine every year minimizes the risk of contracting the illness. People with chronic health conditions or a BMI of 30 or higher, the elderly, and children who are more susceptible to developing complications from the seasonal flu are advised to take it.

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