IT is the most extensive winter vaccination campaign ever undertaken by the NHS, with millions being offered the flu vaccine, while concerns remain over any possible impact from Brexit.

The campaign is underway?

The NHS flu vaccination programme is now available across Scotland and across the UK for the over-65s, children aged up to 11, healthcare workers and those with chronic health conditions.

And it’s the biggest ever?

Around 30 million people - nearly half of the UK population - are being offered the vaccine.

And this year there are four different types of vaccine, each designed specifically to maximise protection within the different groups.

It’s a killer?

In the most serious cases flu can bring on pneumonia or other serious infections which can result in death. Last winter was relatively mild, with 35 people dying from flu in Scotland, down from 331 a year earlier.

Australia has sparked concerns?

There has been a significant increase in the number of cases reported this year in Australia, with three times as many flu deaths than the previous year and concerns the trend could be mirrored elsewhere.

Dr Daniel Jernigan, director of the influenza division of the Centres for Disease Control and Prevention in the US, said: “It’s too early to tell for sure, because sometimes Australia is predictive and sometimes it’s not.”

How do you get flu anyway?

The virus is contained in the millions of tiny droplets that splutter out of the nose and mouth when someone who is infected coughs or sneezes. The droplets spread about one metre and hang in the air for a spell, before landing on surfaces, where the virus can survive for up to 24 hours.

Anyone who breathes in the droplets can catch flu. You can also catch the virus by touching the surfaces that the droplets have landed on.

But I had it last year?

Flu viruses mutate regularly, so you can catch flu many times and your body will not have a natural resistance to the new strains.

What about Brexit?

Vaccine manufacturers were all asked to ensure supplies would be in the UK by October 31 - the deadline for the UK’s departure from the EU. Typically, deliveries continue into November and December.

So far, only one supplier has said they will miss this deadline. Sanofi Pasteur added, though, that it will ship one delivery of one million doses, for those with chronic health conditions, in November and said it also has contingency plans ready if there are any issues using the Dover port.

The advice is?

To get the vaccine.

Dr Jim McMenamin, who leads the seasonal flu immunisation programme at Health Protection Scotland, said: "We can't emphasise enough that the facts show the flu vaccine is the safest and most effective way to help protect against flu and its complications. Getting the vaccine only takes a few minutes and helps to provide protection from flu for around a year. Contact your GP practice now, and get protected for winter.”