Influenza commonly known as flu, is an acute respiratory disease caused by various types of influenza viruses. Three types of influenza viruses are recognized: A, B and C, among which Type A is more prevailing. Influenza occurs in Hong Kong throughout the year, and the two subtypes of influenza A virus, namely H1N1 and H3N2, are most commonly seen. In Hong Kong, the disease is more prevalent in January-March and July-August. Emergence of new subtypes occurs from time to time at irregular intervals. They are responsible for widespread outbreaks and necessitate periodic reformulation of influenza vaccine.

Influenza is a highly infectious viral disease which mainly spreads from person to person through air or droplets in crowded spaces. It may also be spread by direct contact with infected secretions. The incubation period is short, usually around 1-3 days. Symptoms include fever, headache, muscle ache, stuffy and runny nose, sore throat, cough and general tiredness.

Influenza is usually self-limiting and will recover within 2 to 7 days among healthy people. General nursing care and symptomatic relief is recommended. However, elderly people and those with chronic diseases (such as cardiovascular, chronic respiratory illnesses) may have a higher risk of getting complication, for example, bronchitis, pneumonia, etc.

Therefore, young children, elderly, people with chronic illnesses and individuals with weakened body resistance should consult their doctors for medical advice promptly if they develop symptoms of respiratory tract infection. Antibiotics should not be used as influenza is caused by viruses while antibiotics is used only when the illness is complicated by bacterial infection. Symptomatic treatment cannot kill the influenza viruses but is useful in relieving symptoms. Anti-fever medicine, cough syrup and throat lozenge, etc, may be prescribed by the doctors to alleviate the symptoms. Aspirin should not be used in children because it may cause Reye΅¦s Syndrome which is a rare complication involving the central nervous system and the liver.

Infected person should comply with the following advice:

• have adequate rest and sleep;
• maintain good personal hygiene and wear face mask;
• wash hands with soap and water after sneezing or coughing or handling of respiratory secretion;
• do not spit;
• cover mouth and nose with tissue paper while sneezing or coughing;
• all sputum and nasal secretion should be wrapped up properly with tissue paper and dispose properly in a lidded rubbish bin.

Building up good body immunity and practicing healthy lifestyle is the most effective way to prevent influenza. This can be achieved by having adequate rest, eating a balanced diet, getting regular exercise, reducing stress and avoiding smoking. Members of the public can consult their doctors for getting yearly influenza vaccination.

Guidelines for Good Handwashing
Handwashing, when done correctly, is an important personal hygiene practice to prevent contracting and spreading communicable diseases.

When should we wash our hands?
1. Before touching the eyes, nose and mouth
2. Before eating or handling food
3. After using the toilet
4. When hands are contaminated by respiratory secretions, e.g. after coughing or sneezing
5. After touching public installations or equipment, such as escalator handrails, elevator control panels or door knobs
6. After changing diapers or handling soiled articles when looking after young children or the sick

Steps for good handwashing
1. Wet hands under running water.
2. Apply liquid soap and rub hands together to make a soapy lather.
3. Away from the running water, rub the palms, backs of hands, between fingers, backs of fingers, thumbs, finger tips and wrists. Do this for at least 20 seconds.
4. Rinse hands thoroughly under running water.
5. Dry hands thoroughly with either a clean cotton towel, a paper towel, or a hand dryer.
6. The cleaned hands should not touch the water tap directly again.
- The tap may be turned off by using the towel wrapping the faucet; or
- after splashing water to clean the faucet; or
- by another person.

Please note:

• Towels should never be shared.
• Used paper towel should be properly disposed of.
• Personal towels to be reused must be stored properly and washed at least once daily. It is even better to have more than one towel for frequent replacement.
• When hands are not visbly soiled, application of 70-80% alcohol-based handrub is equally effective for disinfection.

Information from Centre for Health Protection