Hello and welcome to the zero to finals podcast.

My name is Tom and in this episode I'm going to be talking to you about influenza or flu.

And if you want to follow along with written notes on this topic,

you can follow along at zero definals.com slash influenza or in the infectious diseases section of the Zero to Finals Medicine book.

So let's get straight into it.

The influenza virus is an RNA virus and there are three types, A, B and C, of which

A and B are the most common.

The A type has different H and N subtypes.

Examples of different A-type strains are H1N1, which you might know as swine flu,

and H5N1, which you might know as avian flu. Outbreaks of influenza typically occur during winter, so we call this

flu season, and they particularly affect people who suffer with chest problems such as COPD or asthma.

There is a flu vaccination and every year the vaccine is changed to target multiple strains of influenza that are most likely to cause flu that year.

So it needs to be given yearly to keep the person protected from developing flu.

And there's a bit of a guessing game before the flu season to decide which flu virus is most likely to cause problems that year.

The flu vaccine is given free on the NHS to people who are at higher risk of developing

flu or flu related complications.

So these are people who are 65 and over, young children, pregnant women, chronic health

conditions such as asthma, COPD, heart failure or

diabetes, and healthcare workers and carers who might pick up the flu from patients and spread them to

other people. So how do patients with influenza present? What typical features are fever, carisal symptoms, so runny, snotty nose, sneezing,

that sort of thing, lethargy and fatigue, anorexia, which essentially means loss of appetite,

muscle and joint aches, headaches, dry cough, sore throat, and generally feeling very under the weather.

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