The rise of the H1N1 virus as a global health concern is a reminder of how the flu virus can mutate into more dangerous forms from time to time. There are three main types of the flu virus: Influenza A, B and C. H1N1, which is carried in pigs and transmitted to humans, is a subtype of Influenza A virus.

Here are some common questions regarding the fly, and tips on how to keep the flu bug at bay.

Can the common flu lead to more serious problems?

Yes, it can lead to problems such as pneumonia, myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the pericardium, a protective lining that surrounds the heart) - especially in the very young and very old.

Pregnant women and immuno-suppressed or chronically-ill patients are also at risk of flu related complications.

How can we build up our immunity against the flu virus?

Exercise regularly; get adequate sleep; drink lots of water -at least six to seven glasses daily; and eat plenty of fruits and vegetables.

Can a flu shot offer us any protection?

The influenza virus vaccine is used to stimulate active immunity and provides protection against influenza virus strains, as well as against closely related strains, contained in the vaccine. It can be 80 to 90 per cent effective, depending on the individual. However, the vaccine is not effective against all strains of influenza virus.

Do we need regular flu shots?

Flu vaccinations, once a year, are recommended for those who are at high risk of flu or flu related complications, as well as those who live with, or care for, such individuals. They include women who will be pregnant or planning to get pregnant during the flu season; those with chronic lung (including asthma), heart (except hypertension); kidney, liver, blood, or metabolic disorders; immuno-suppressed patients; and those who take care of the elderly or children under five.

Healthcare workers, residents of nursing homes and people who will be travelling overseas during the flu season should also get annual vaccinations.

Who should avoid getting flu shots?

Flu vaccinations are not recommended for those who are allergic to eggs, chicken protein, formaldehyde, gentamycin; and women in the first 14 weeks of their pregnancy.

Is self-medication - buying anti-flu tablets off the counter - recommended when you have the flu?

If the symptoms persist more than a few days, it is best to see a doctor. For patients in the higher risk group, self-medication is not recommended.

If a person has the flu, what can he and the rest of his family do to avoid spreading the infection?

The patient himself should cover his mouth with a tissue whenever he coughs or sneezes. The rest of the family should not share eating utensils with the patient and wash their hands frequently. If possible, try not to sleep in the same room as the patient. If there are family members who are in the vulnerable group, it would be good practice for them - and the patient - to wear masks.