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Facts About Seasonal Influenza (Flu) and Flu Shot (Vaccine)

Dr. M. Vijayalakshmi, M.D (Peds), M.D (USA), F.A.A.P

"AllForKids Pediatric and Adolescent Clinic"
"Content Source: CDC"

The flu is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness.

Some people, such as older people, young children, and people with certain health conditions, are at high risk for serious flu complications.

What is Influenza (Flu)?

The flu is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness.

Some people, such as older people, young children, and people with certain health conditions, are at high risk for serious flu complications.

Symptoms of Flu

Symptoms of flu include:

  • Fever (usually high) , headache , extreme tiredness , dry cough , sore throat
  • Runny or stuffy nose , muscle aches
  • Stomach symptoms, such as nausea, vomiting, and diarrhea, also can occur but are more common in children than adults
Complications of Flu

Complications of flu can include bacterial pneumonia, ear infections, sinus infections, dehydration, and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes.

How Flu Spreads

Flu viruses spread mainly from person to person through coughing or sneezing of people with influenza. Sometimes people may become infected by touching something with flu viruses on it and then touching their mouth or nose. Most healthy adults may be able to infect others beginning 1 day before symptoms develop and up to 5 days after becoming sick. That means that you may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick.

Preventing Flu: Get Vaccinated

Key Facts About Flu Vaccine

The single best way to protect against the flu is to get vaccinated each year.

The "flu shot"-is an inactivated vaccine (containing killed virus) that is given with a needle, usually in the arm. The flu shot is approved for use in people older than 6 months.

Each vaccine contains three influenza viruses-one A (H3N2) virus, one A (H1N1) virus, and one B virus. The viruses in the vaccine change each year based on international surveillance and scientists' estimations about which types and strains of viruses will circulate in a given year.

About 2 weeks after vaccination, antibodies that provide protection against influenza virus infection develop in the body.

Note: This vaccine is available in India.
When to Get Vaccinated

October through February is the ideal time to get vaccinated.

Who Should Get Vaccinated

In general, anyone who wants to reduce their chances of getting the flu can get vaccinated. However, it is recommended that certain people should get vaccinated each year. They are either people who are at high risk of having serious flu complications or people who live with or care for those at high risk for serious complications.

People who should get vaccinated each year are:

  • People at high risk for complications from the flu, including:
    • Children aged 6 months until their 5th birthday,
    • Pregnant women,
    • People 50 years of age and older, and
    • People of any age with certain chronic medical conditions;
    • People who live in nursing homes and other long term care facilities.
  • People who live with or care for those at high risk for complications from flu, including:
    • Household contacts of persons at high risk for complications from the flu
    • Household contacts and out of home caregivers of children less than 6 months of age (these children are too young to be vaccinated)
    • Healthcare workers.
Who Should Not Be Vaccinated

There are some people who should not be vaccinated without first consulting a physician. These include.

People who have a severe allergy to chicken eggs , People who have had a severe reaction to an influenza vaccination in the past , People who developed Guillain-Barré syndrome (GBS) within 6 weeks of getting an influenza vaccine previously , Influenza vaccine is not approved for use in children less than 6 months of age, People who have a moderate or severe illness with a fever should wait to get vaccinated until their symptoms lessen.

Vaccine Effectiveness

The ability of flu vaccine to protect a person depends on the age and health status of the person getting the vaccine, and the similarity or "match" between the virus strains in the vaccine and those in circulation.

Vaccine Side Effects (What to Expect)

Different side effects can be associated with the flu shot and LAIV.

The flu shot: The viruses in the flu shot are inactivated, so you cannot get the flu from a flu shot. Some minor side effects that could occur are

  • Soreness, redness, or swelling where the shot was given
  • Fever (low grade)
  • Aches

If these problems occur, they begin soon after the shot and usually last 1 to 2 days. Almost all people who receive influenza vaccine have no problems from it.

References:

Center for Disease Control and Prevention.

Remember, there is no substitute for medical advice that comes from a pediatrician after they have evaluated your child. This document is only for informational purposes and is not a substitute for medical advice.