Clearing the Air on Flu

By Dr. Shyam Kukreja in Paediatrics (Ped)

Jul 28 , 2016 | 4 min read

Q. We have heard a lot about flu from media, is it same as cold?

Though both flu and common cold are respiratory illnesses but they are caused by different viruses. Influenza or "the flu" develops when a flu virus infects the respiratory system including your nose, throat, air way tubes, and sometimes the lungs. However, a cold virus usually infects the upper respiratory tract primarily your nose and throat. Flu can cause a severe illness as compared to common cold. It can also bring fever, exhaustion, body aches – few symptoms that are rarely caused by common cold.

Q. What is swine flu which has been in the news for last few years?

At any given time, there are several types of flu strains in the world. In 2009 a new virus developed named as swine flu (H1N1). This caused more severe disease than the other seasonal flu viruses.

Q. How did this new virus develop? From where it came? 

The flu virus has genome which is very unstable and keeps changing minimally (mutating) and keeps acquiring different looks. This minor change is known as "antigenic drift". This new drifted flu virus eludes the human immune response by becoming unrecognisable. That’s why every year a new vaccine is manufactured.

If two entirely different strains of flu viruses, human flu virus and a flu virus circulating among ducks co-infect a pig, then the reassortment of genomes of two different flu viruses lead to development of a novel flu virus. This is known as "antigenic shift". Swine flu is developed by this process. Several such viruses keep developing. If any of the novel virus has the capability of easy transmission from one to another person then it has the potential to cause epidemic and pandemic. No human immune system would be able to defend  against the new virus as there has not been any past exposure. Such a new virus may be originally of mild or deadly variety or may become deadly by minor drifts during person to person transmission.

Q. Hasn’t this threat always been there ?

This threat has always been there since time immemorial. 1918 Spanish flu is the most serious pandemic recorded in history. It was responsible for approximately 50-100 million deaths world wide. There have been about three influenza pandemics in each century for the last 300 years, the most recent one being the 2009 flu pandemic.

Q. How flu spreads from person to person? 

Flu (Influenza) is transmitted through air from the respiratory tract of an infected person by coughing. It can also be transmitted by direct contact with respiratory droplets. 

Q. How long does it take to develop symptoms of influenza after being exposed? 

The incubation period of influenza is usually two days but can range from one to four days. 

Q. What are the symptoms of influenza? 

Typical influenza disease is characterized by:

  • abrupt onset of fever,
  • aching muscles,
  • sore throat and
  • non-productive cough

Additional symptoms may include runny nose, headache, a burning sensation in the chest and eye pain and sensitivity to light. The flu is usually at its worst for three to four days. The cough may linger longer. Recovery may take seven to 10 days. You may have lingering fatigue for several weeks.

Q. Does every person infected with flu go through same suffering?    

Typical influenza disease does not occur in every infected person. Some one who has been previously exposed to similar virus strains (through natural infection or vaccination) is less likely to develop serious clinical illness. 

Though Influenza disease can occur among people of all ages; however, the risks for complications, hospitalizations and deaths are higher among people age 65 years or older, young children and people of any age who have suppressed immune systems or certain chronic medical conditions like people with diabetes, people with lung disease, people with neurologic disease and people with heart disease. Pregnancy also increases the risk for serious medical complications from influenza .

Q. If I have allergies, am I more likely to get the flu?

No, allergies don't affect susceptibility to the flu. But people with asthma are more likely to have complications such as pneumonia if they get flu.

Q. If I contract influenza, what should I do? 

You will need to get plenty of rest and drink a lot of liquids. You can take medications to relieve the symptoms of influenza (but never give aspirin to children or teenagers who have influenza-like symptoms).  Anti-cold medicines give relief from fever, aches, stuffy nose, and cough though they don't "cure" the flu but may help keep you more comfortable. If you are at a high risk of developing complications from influenza, you should consult your doctor as you may need specific antiviral medicines.

Q. Should I get an antibiotic?

Antibiotics will not help treat the flu. Antibiotics kill bacteria but they do not kill any viruses including ones that cause the flu.

Q. Can you get influenza more than once and what is the best way to prevent it?

Yes. Influenza viruses change frequently and infection with one strain does not provide protection against all other strains. Annual vaccination is the best way to prevent influenza. 

Q. Is there an alternative to vaccination in preventing influenza? 

Vaccination is the principal means of preventing influenza and its complications. Here are some additional steps that may help prevent the spread of respiratory illnesses like influenza: 

  1.  Cover your nose and mouth with your sleeve or a tissue when you cough or sneeze (cough etiquette)
  2.  Wash your hands often with soap and water, especially after you cough or sneeze. If you are not near water, use an alcohol-based hand cleaner.
  3.  Stay away as much as you can from people who are sick.
  4.  If you get influenza, stay home from work or school for at least 24 hours after the fever has ended. If you are sick, don’t go near other people to avoid infecting them.
  5.  Try not to touch your eyes, nose, or mouth. Germs often spread this way.

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