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Influenza (Flu)

Influenza, commonly known as "the flu", is an infectious disease caused by an influenza virus. Symptoms can be mild to severe. The most common symptoms include: a high fever, runny nose, sore throat, muscle pains, headache, coughing, and feeling tired.

PubMed Health Glossary
(Source: Wikipedia)

About the Flu

People often talk about having the flu (influenza) when they come down with a cold. Yet the two illnesses progress in very different ways and also typically have different signs and symptoms.

Colds are much more common than the flu. They also start quite slowly, while the viruses that cause the flu strike quickly and cause more severe symptoms, even in people who are otherwise quite healthy. The flu makes you feel very ill very quickly. A cold does not usually cause any serious harm, and is over within a week with or without treatment. It is a good idea to see a doctor if you have the flu, and it may take some time before you fully recover.

Cold and flu treatments mainly aim to relieve symptoms. The only medicines available that fight directly against the flu viruses can at most reduce the time someone is ill. But a number of things can be done to avoid infection in the first place...
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What works? Research summarized

Evidence reviews

Vaccines to prevent influenza in healthy adults

We evaluated the effect of immunisation with influenza vaccines on preventing influenza A or B infections (efficacy), influenza‐like illness (ILI) and its consequences (effectiveness), and determined whether exposure to influenza vaccines is associated with serious or severe harms. The target populations were healthy adults, including pregnant women and newborns.

Neuraminidase inhibitors for influenza: a systematic review and meta-analysis of regulatory and mortality data

The study found that the neuraminidase inhibitors oseltamivir and zanamivir cause small reductions in the time to first alleviation of influenza symptoms in adults. Oseltamivir increases the risk of nausea, vomiting, psychiatric events in adults and vomiting in children and has no protective effect on mortality among patients with 2009A/H1N1 influenza.

Influenza vaccine for children and adults with bronchiectasis

In many countries, influenza vaccination is an accepted part of routine immunisation recommendations particularly in persons 65 years and over, those in long‐term care facilities and also adults and children with chronic illnesses including those with bronchiectasis. In this review however, our search for randomised control trials examining the effectiveness of influenza vaccines for people with bronchiectasis revealed no relevant studies. In the absence of evidence, patients' needs should be individualised and national guidelines be adhered to.

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Summaries for consumers

Vaccines to prevent influenza in healthy adults

We evaluated the effect of immunisation with influenza vaccines on preventing influenza A or B infections (efficacy), influenza‐like illness (ILI) and its consequences (effectiveness), and determined whether exposure to influenza vaccines is associated with serious or severe harms. The target populations were healthy adults, including pregnant women and newborns.

Influenza vaccine for children and adults with bronchiectasis

In many countries, influenza vaccination is an accepted part of routine immunisation recommendations particularly in persons 65 years and over, those in long‐term care facilities and also adults and children with chronic illnesses including those with bronchiectasis. In this review however, our search for randomised control trials examining the effectiveness of influenza vaccines for people with bronchiectasis revealed no relevant studies. In the absence of evidence, patients' needs should be individualised and national guidelines be adhered to.

Homeopathic Oscillococcinum® for preventing and treating influenza and influenza‐like illness

To determine whether homeopathic Oscillococcinum® is more effective than placebo in the prevention and/or treatment of influenza and influenza‐like illness in adults or children.

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Terms to know

Influenza A Virus
One of three types of virus that cause the illness called influenza (flu). The influenza A virus can infect people, birds, pigs, horses, and other animals. It is the main cause of most influenza epidemics.
Influenza Viruses (Flu Viruses)
Three types of influenza viruses affect people, called Type A, Type B, and Type C. Usually, the virus is spread through the air from coughs or sneezes. It can also be spread by touching surfaces contaminated by the virus and then touching the mouth or eyes.
Neuraminidase Inhibitors
Neuraminidase inhibitors are a class of drugs which block the neuraminidase enzyme. They are commonly used as antiviral drugs.
Upper Respiratory Tract Infections (URTI)
An infectious process affecting the upper respiratory tract (nose, paranasal sinuses, pharynx, larynx, or trachea). Symptoms include congestion, sneezing, coughing, fever, and sore throat.
Viruses
In medicine, a very simple microorganism that infects cells and may cause disease. Because viruses can multiply only inside infected cells, they are not considered to be alive.

More about Influenza

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See Also: Common Cold

Other terms to know: See all 5
Influenza A Virus, Influenza Viruses (Flu Viruses), Neuraminidase Inhibitors

Related articles:
Protecting Yourself From Respiratory Infection
About Flu Vaccines

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