Influenza, more commonly known as the flu, is a contagious respiratory illness caused by influenza viruses. There are 3 types: influenza A, B and C. Influenza A and B can cause severe disease and death, and can lead to epidemics, while influenza C causes mild infections and typically does not lead to epidemics.
Flu viruses can infect your nose, throat and lungs, potentially causing complications such as ear infections, pneumonia, bronchitis, sinus infections and even heart problems. In serious cases, flu can even lead to death.
People with the flu often experience the following symptoms: fever, chills, body aches, persistent cough, headache, sore throat, nasal congestion, and fatigue. Although more common in children than adults, some may even experience vomiting and diarrhoea.
Flu usually goes away in 1 – 2 weeks and isn't serious. However, children and adults who are of higher risk may develop complications. Pneumonia is the most serious complication and can be deadly.
Factors that may increase the risk of developing flu or its complications:
Flu viruses are spread mainly by tiny droplets when an infected person talks, coughs or sneezes and other people inhale the viruses. Flu can also be spread indirectly when a person touches a surface or object that has the flu virus on it, and then touch their own nose or mouth. A person can get infected if they share food with an infected person without a separate serving spoon.
If you have the flu, you should stay home to recover to avoid spreading the virus to others. Reducing face-to-face contact with others and wearing a mask is important to prevent the spread of flu.
Worldwide, according to World Health Organisation estimates, annual epidemics lead to about 3 – 5 million cases of severe illness, and about 290,000 – 650,000 deaths every year.
In Singapore, there is an estimated 630,000 flu infection cases in a year, leading to 520,000 visits to the doctor, and 315,000 days of absence from work. Every year, approximately 4,200 elderly persons are hospitalised due to the flu and pneumonia, giving rise to 1,450 deaths.
Early diagnosis and treatment can help protect you from flu complications. If you are feeling ill with some or all of the above symptoms, you should speak to your doctor early, preferably within 48 hours, to confirm the diagnosis. Your doctor will conduct a physical exam, look for signs and symptoms of influenza, and may order a test such as a nose swab, to detect the influenza virus.
Antiviral flu medications are available to treat the flu by reducing the replication of the virus. This can help to shorten the duration of the illness and reduce the risk of complications. They are most effective when started within 2 days of onset of the illness.
Antiviral medications are not a substitute for getting a flu vaccine. Getting a flu vaccine is still the best way to prevent yourself and your loved ones from getting the flu virus.
Getting a flu vaccination is an effective way to protect you and your loved ones from flu and its complications. Studies show that flu vaccination reduces the risk of flu illness by between 40 – 60% among the overall population during seasons when most circulating flu viruses are well-matched to the flu vaccine.
It is important to get vaccinated every year because flu viruses mutate so quickly, and last year's vaccine may not protect you from the new strains this year. Also, when you get the vaccine, your immune system produces antibodies to protect you from the virus. However, levels of antibodies may decline over time so getting vaccinated on a regular basis helps you have continued protection.
Benefits of getting the flu vaccination include:
Common side effects of the flu vaccine are developing a mild fever, experiencing swelling, soreness or redness at the injection side, and body aches.
You should talk to your doctor before getting a flu vaccine if you:
The flu vaccine isn't 100% effective. In addition to getting the vaccine, it is also important to incorporate the following measures to reduce the spread of infection: