Influenza or Flu: Contagious. Who is at risk? What are the symptoms of flu? Treatment and prevention

SciGuru.com: An infection can occur due to microbes from within the body or from outside the body. For an infectious agent to enter from outside the body, these microbes must break the mechanical barriers such as skin that separate the body from the surroundings. Examples of infection arising through outside agents are infection from a penetrating wound and infection through the breathing air. Whereas when an appendix is ruptured the septic infection is due to microbes existing within the body entering the blood. Influenza, commonly called as flu, is an infection from outside the body. It is a contagious respiratory illness caused by influenza viruses and affects mainly the nose, throat, bronchi and sometimes lungs.

Electron Microscopy image of negatively stained influenza virions, magnified approximately 100,000 times

According to the Center for Diseases Control (CDC), Atlanta, each year about 36,000 people die from flu-related diseases. 5 to 20% of the population gets flu and on average more than 200,000 people are hospitalized from flu-related complications. Therefore, flu is simply not a personal health issue; it is an enormous social and economic problem too.

Who is at risk?

Young children, the elderly, and people with some medical conditions are at high risk for serious complications due to flu. Though most healthy people recover from flu, those at high risk need to be very careful. They should consult a physician as soon as a flu is suspected

Is flu life-threatening?

Flu can be life threatening, especially to people at risk. Influenza infection can lead to severe complications, pneumonia and death. Other complications or flu shot dangers may include ear infections, sinus infections, dehydration and worsening of chronic medical conditions such as congestive heart failure or asthma.

Can flu be prevented?

According the CDC, "the best way to prevent seasonal flu is by getting a seasonal flu vaccination each year". Currently there are two different vaccines for flu:

1. Flu shot: A flu shot vaccine contains killed or inactivated virus. The virus is not infectious, but the dead viral particles initiate an immune response in the recipient so that the body develops immunity against this particle. When a similar virus attacks the body later, the specific immune response enabled in the body due to prior immunization kills or inactivate the virus. This vaccine is given by a needle shot, so it is called flu shot. The seasonal flu shot is approved for use in people 6 months of age and older, including healthy people and people with chronic medical conditions (cdc.gov).

2. Nasal spray: This technique uses live virus, but they are weakened and therefore called live attenuated influenza vaccine or LAIV. According to CDC, "LAIV is approved for use in healthy people 2-49 years of age who are not pregnant."

Do not expect that the individual will be protected from flu immediately after vaccination. It takes about two weeks for the body to mount a strong antibody response against the administered viral particles. Because this response is specific to the particles used to immunize, the individual will not be protected against flu like symptoms or infection due to non-influenza viruses. The protection also may not be efficient against flu viruses that differ from the original immunizing virus.

Is there any treatment for flu?

Flu symptoms should be evaluated by a qualified physician. The evaluation of the patient may include physical exam, blood work and/or x-ray depending on the symptoms and condition of the patient. Though flu may be prevented by annual vaccination, antiviral medications with activity against influenza viruses may be effective for the prevention and treatment of influenza.

On September 8, 2009 CDC updated its recommendations for the use of influenza antiviral medicines to provide additional guidance for clinicians in prescribing antiviral medicines for treatment and prevention (chemoprophylaxis) of influenza during the upcoming 2009-2010 flu season. These recommendations are intended to help clinicians prioritize use of antiviral drugs for treatment and prevention of influenza. In general, the priority for the use of antiviral medications 2009 season continues to be in persons at increased risk of influenza-related complications as outlined in the antiviral recommendations posted on May 6, 2009.

For details see: CDC Flu Recommendations This report states that "Treatment with oseltamivir or zanamivir is recommended for all persons with suspected or confirmed influenza requiring hospitalization." This recommendation further adds that: "Actions that should be taken to reduce delays in treatment initiation include: Informing persons at higher risk for influenza complications of signs and symptoms of influenza and need for early treatment after onset of symptoms of influenza (i.e., fever, respiratory symptoms); Ensuring rapid access to telephone consultation and clinical evaluation for these patients as well as patients who report severe illness; Considering empiric treatment of patients at higher risk for influenza complications based on telephone contact if hospitalization is not indicated and if this will substantially reduce delay before treatment is initiated."

Symptoms of flu and the need for annual vaccination

Should I get a vaccine or not for flu?

Though vaccination is generally advised as a prevention for flu, some people are not advised to take vaccine. The Center for Diseases Control (CDC), USA advises the following to take a vaccine:

-Children aged 6 months up to their 19th birthday
-Pregnant women
-People 50 years of age and older
-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: health care workers, 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).

The following are advised not to take a vaccine, by CDC:

-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 Barre Syndrome (GBS) within 6 weeks of getting an influenza vaccine previously.
-Children less than 6 months of age (influenza vaccine is not approved for use in this age group).
-People who have a moderate or severe illness with a fever should wait to get vaccinated until their symptoms lessen. But the final decision should taken by the patient in consultation with a qualified physician.

Why should I take a flu shot every year?

The vaccine is good only against viruses that are same or very close to the viral particles used for immunization. To understand it further, consider the analogy of a lock and key. The key made is good only for the specific lock, when the lock is slightly changed, the key may stop working. There are several different strains of viruses. Every year it may be a different form of the virus that spreads. The immunization carried out during the previous year may not be useful for the current year. Therefore it is advised that immunization may be done every year.

What are the symptoms of flu?

Influenza is characterized by the sudden onset of fever (often high), aching muscles, extreme tiredness, headache, non-productive cough, sore throat and runny or stuffy nose. The most prominent of the respiratory symptoms is usually a dry, hacking cough. Most people also develop a sore throat and headache. Runny nose (nasal discharge) and sneezing are common. Flu symptoms can make you feel miserable. A doctor’s exam may be required to determine if you have flu, cold or complications of flu. The initial symptoms of flu may be mild, but it can become severe without much notice. Therefore one needs to be on careful if there is someone with flu in the household or at workplace. Seasonal flu usually has a predictable pattern, beginning in the fall and ending in the spring. When flu is suspected, one should consult a physician. This will help in proper diagnosis, evaluation of risk , treatment and management of flu.



Disclaimer: The above material is only for information purpose and some information may change with advancement of knowledge. Do not use this information to treat any medical condition. If you suspect a medical condition, consult a registered medical practitioner.

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