Influenza or flu is a very common viral infection that afflicts many individuals at any stage in their life. It is caused by the influenza virus, which is an airborne organism that can be transmitted by inhaling the air that is expired by an infected person. The ease of transmission of this infection is the reason for the several flu pandemics that have occurred in the past. These pandemics (or spread of infection in a worldwide scale) include the Spanish flu in 1918, the Asian flu or avian flu in 1957, the Hong Kong flu in 1968, the Russian flu in 1977, and the H1N1 or swine flu pandemic in 2009.

Signs and symptoms

The influenza virus is a virus that attacks the respiratory system from the nose, to the throat, and down to the lungs. Hence, flu is usually characterized by respiratory symptoms that are associated with systemic signs. These include:

Fever and chills

  • Cough
  • Body pain and muscle aches
  • Sore throat
  • Headache
  • Dizziness
  • Vomiting
  • Runny nose – infrequent

When to see a doctor

Flu is usually a moderate, self-remitting infection. Most healthy individuals who get the flu recover from the infection within a week to 10 days even without treatment. However, in some individuals who are immunocompromised or whose immune systems are not mature enough to battle infections, the flu can be fatal. These individuals include:

  • Young children and the elderly
  • Individuals with weak immune system like those with HIV, cancer, and diabetes
  • Individuals who are taking medications that suppress the immune system like those who underwent transplant or those undergoing chemotherapy
  • Individuals with existing respiratory conditions like asthma or COPD

These individuals must be brought to the doctor if suspected to have flu. In addition, the presence of the following signs and symptoms in any individual with flu warrants a trip to the doctor:

  • Difficulty of breathing
  • Wheezing
  • Increased somnolence or difficulty in staying awake
  • Stiff neck
  • Rash
  • Confusion
  • If child, will not wake up or will not interact with you
  • If child, has a fever with a rash
  • If child, turning blue or cyanotic


The diagnosis of flu is made clinically, that is, it is based on history and physical examination. Tests are rarely needed to confirm the diagnosis. If in case it is warranted, like in cases of outbreaks, a blood culture is usually done to identify the exact viral strain that caused the infection.


The treatment for flu in most healthy individuals follows the principle of watchful waiting. Flu will usually resolve within 5 to 7 days even without intervention. There is no need to give antibiotics for flu because it is caused by a virus. Most medications for flu are only for symptomatic relief, for example, for the relief of headache or fever. Some steps that could be done for supportive management of flu are:

  • Increase fluid intake to prevent dehydration from fever.
  • Get plenty of rest
  • Use a room humidifier to relieve clogged nose.
  • Try over-the-counter medications for fever, headache or body pain. Examples of these medications are acetaminophen and ibuprofen (NSAIDS). Other supportive treatments for fever include drinking fluids to avoid dehydration, rest, and sponge baths to lower the body temperature.

Aspirin, a common pain medication, should NOT be given to children because it can cause Reye’s syndrome. Reye’s syndrome is a rare but potentially fatal condition that is characterized by rashes, seizures and confusion due to the swelling of the brain and the liver.

Some doctors might prescribe anti-virals to shorten the period of flu symptoms. This is particularly helpful in immunocompromised individuals who would benefit from a faster recovery of even just a day or two. However, not all strains of influenza are susceptible to antivirals, so it’s still not a foolproof medication and it must be started within first 48 hours to get maximal benefit.  Antibiotics which target bacteria will not work for flu.


The best method for preventing the flu is through vaccination. Different vaccines have been developed to protect individuals against the different strains of flu. All people age 6 months or older should get the flu vaccinations yearly, especially the immunocompromised people. You might wonder why there is a need to get vaccines every year. Isn’t a single set of vaccination enough? The influenza virus has the ability to mutate; that is why new strains of influenza appear regularly all over the world. Every year, new vaccines have to be created to protect against the recent strains of influenza. That is why flu vaccinations should be done every year.

The flu vaccine comes in different forms, including:

  • A shot that goes into muscle (usually in the upper part of the arm)
  • A nasal spray
  • A shot that goes under the skin

Many people refuse being vaccinated because of their fear of the complications from the vaccines. To date, no scientific study has ever proven the claims that vaccines can cause autism. In addition, flu vaccines do not cause flu. Those who get flu-like symptoms after being vaccinated most probably have already been infected by the virus even before they got the shot. The side effects of a flu vaccine are redness, pain, and swelling over the area of injection, mild fever, mild rash, and, at most, some rare allergic reactions.

Getting a flu vaccine is protective not only for the individual who gets the shot but also for the individuals around him. Once a person is protected from getting the flu, then he cannot be infected and will not be able to transmit the infection to other people. Therefore, getting a flu vaccine not only protects you but also the people around you like your family and friends. Other steps that could help prevent the spread of the flu virus are the following:

  • Do not go to public areas if you know that you have the flu. Do not go to work or to school.
  • Wear a mask.
  • Wash your hands regularly with soap and water.
  • Cover your mouth when you cough or sneeze.

Pregnant Women

The flu can be very dangerous for pregnant women. All pregnant women should get the flu vaccine. You should call your doctor immediately if you think you might have been exposed to the flu or if you develop symptoms. Complications can include shortness of breath and even death. Antiviral medicine to prevent progression are a must.