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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.

Interventions to increase influenza (flu) vaccination uptake for people aged 60 and older

Many health authorities recommend influenza vaccination of older people. However, vaccination uptake in people aged 60 and older varies across countries, socioeconomic and health‐risk groups. It is important to identify effective interventions to increase influenza vaccination uptake.

Regulatory information on trials of oseltamivir (Tamiflu) and zanamivir (Relenza) for influenza in adults and children

Oseltamivir and zanamivir have been stockpiled in many countries to treat and prevent seasonal and pandemic influenza, before an influenza vaccine matched to the circulating virus becomes available. Oseltamivir is classified by the World Health Organization as an essential medicine.

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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.

Interventions to increase influenza (flu) vaccination uptake for people aged 60 and older

Many health authorities recommend influenza vaccination of older people. However, vaccination uptake in people aged 60 and older varies across countries, socioeconomic and health‐risk groups. It is important to identify effective interventions to increase influenza vaccination uptake.

Regulatory information on trials of oseltamivir (Tamiflu) and zanamivir (Relenza) for influenza in adults and children

Oseltamivir and zanamivir have been stockpiled in many countries to treat and prevent seasonal and pandemic influenza, before an influenza vaccine matched to the circulating virus becomes available. Oseltamivir is classified by the World Health Organization as an essential medicine.

See all (50)

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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