Should YOU have a flu jab? As up to half the country are offered it, read our ultimate guide to whether it’s worth it – and how to make it work better if you do get it

An estimated 30 million people in the UK – almost half the entire population – are being offered a flu vaccine to reduce their chances of infection this winter.

The jab is free and, while far from perfect, can more than halve the risk of falling ill in some people.

It can also save lives: The death toll from flu was over 18,000 people – of all ages – in the last two years alone.

And the vaccine may have benefits beyond flu, with some research suggesting it can cut the risk of dementia by a fifth, as well as reducing heart attacks and stroke in people with cardiovascular disease.

Yet fewer people than ever are having the jab.

Last winter, the proportion of over-65s in the UK choosing to get the flu vaccine dropped from 79.9 per cent to 77.8 per cent, according to the UK Health Security Agency (UKHSA).

Among other eligible groups it was even worse. Only 44 per cent of young children (two and three-year-olds) were vaccinated, and less than a third of pregnant women – even though flu can, in severe cases, cause stillbirth.

Meanwhile, among people in clinical risk groups – for instance, they have asthma or heart disease – the uptake is just 41 per cent.

The UKHSA is calling for more people to have the flu vaccine – this follows the experience in Australia during their recent winter, when thousands were hospitalised (often what happens there is a precursor to what will happen in the UK as the same strains tend to dominate).

There are also fears that a surge at the same time in cases of Covid (a recent spate of cases is partly due to a new variant XEC, which is predicted to become a dominant strain this winter) and respiratory syncytial virus (RSV) – a common cause of coughs and colds – will lead to a ‘tripledemic’ of illness and pile pressure on hard-pressed NHS services.

So just how good is the flu vaccine, when’s the best time to have it – and how can you boost its effectiveness to ensure you get the maximum protection this winter? You might be surprised by the answers…

THE YOUNGER YOU ARE, THE BETTER IT WORKS

Getting the flu vaccine right is a difficult task, since the types of flu viruses in circulation are constantly changing.

In February each year, the World Health Organisation predicts which strains present the greatest threat over the following winter, after which it’s a race – taking six months or more – to produce the hundreds of millions of doses needed globally.

During that time, the flu virus can mutate into new strains not covered by the vaccine.

As a rule, most years the best scientists can hope for is that the flu jab reduces the risk of infection by about 60 per cent.

Last winter, research by the UKHSA showed it was 63 to 65 per cent effective in preventing infection in children (due to their stronger immune reactions to the vaccine); 36 to 55 per cent effective in those aged 18 to 64; and just 40 per cent effective in those over 65. As we age our immune systems naturally weaken, in turn reducing our response to vaccines.

BOOK A MORNING JAB IF YOU CAN

Flu jabs that are given in the morning seem to be better at warding off infection, research suggests.

The latest study shows that older people vaccinated earlier in the day are much less likely to end up in hospital with flu-related complications, reported the Journal of Infection last month.

The researchers tracked more than 12,400 people aged over 70 and found those vaccinated before 11.30am were 12 per cent less likely to need hospital treatment than those who got it later in the day.

The theory is that our immune systems are more alert and responsive first thing, because that’s when our body clocks are getting our defences ready to face any threats from infectious agents we might encounter during the day.

A GOOD NIGHT’S SLEEP IS ESSENTIAL

Getting a good night’s sleep could be the difference between a flu jab that works well and one that offers less protection.

A 2023 study at the Mayo Clinic in Rochester, US, of men over 65, found that those who felt tired on the day of their vaccine was due – and who had a history of poor sleep – responded less well to the jab than men who got a full seven or eight hours’ sleep every night – 28 days after vaccination, poor sleepers had nearly half the level of antibodies seen in good sleepers.

‘If you are tired and run down your immune system is less efficient,’ says Professor Andrew Easton, a virologist at the University of Warwick.

‘In military terms, it means you have fewer troops [i.e. the antibodies] and they are in less good shape to fight off invaders.’

COULD TAKING A PROBIOTIC BOOST YOUR RESPONSE?

One of the simplest ways to turbo-charge your response to the flu jab could be to simply first take a probiotic pill – containing ‘healthy’ bacteria that are good for your gut.

A review of data by Southampton University, published in the journal Age and Ageing in May, found that older people who took probiotic pills made with a type of bacteria called lactobacilli (which protects against bacterial infection and plays an important part in maintaining a healthy immune system) had 30 per cent more flu-busting antibodies than those who didn’t take them.

It’s not yet clear whether simply taking one before a jab is enough to generate this effect, or whether you need to be a regular probiotic user to see the benefits.

WATCH YOUR FAVOURITE COMEDY BEFORE THE JAB ITSELF

It may seem unusual medical advice – but catching an episode of your favourite TV comedy show before you get a flu vaccine might just make it work better.

Research in 2017 by Nottingham University found anything that puts you in a good mood on the day of a jab – such as having a laugh or doing yoga – improves the immune system’s response to it.

It’s thought it helps reduce levels of the stress hormone, cortisol – which can interfere with the immune system’s response to vaccines – on the day of the jab.

…AND GO FOR A BRISK WALK AFTERWARDS

Taking a brisk 90-minute walk straight after having the flu jab could also make it more effective, according to research on mice by Iowa State University in 2022.

It showed that one single 90-minute session of light exercise led to higher antibody levels for at least a month after the jab. Antibodies are the defender cells released by the immune system to thwart viral attacks.

Tests showed that exercise stimulated the release of a protein, interferon alpha, which signals to the immune system to produce more flu-fighting antibodies.

Professor Andrew Easton, a virologist, recommends going for a walk straight after the jab

‘The fitter you are, the better your response to the flu vaccine,’ says Professor Easton.

‘It’s like a well-tuned car engine – all the component parts work much better, in this case the immune system.’

But even if you’re not fit, he would recommend a walk – within your own capabilities.

BUT BEWARE: ITS EFFECT STARTS TO WANE AFTER SIX WEEKS

It takes a fortnight or so for the level of infection-fighting antibodies in your blood to reach their peak. They may plateau at that level for a while, but within a few weeks will start to decline, reducing your protection.

Research in the journal Eurosurveillance earlier this year, involving 53,000 vaccinated adults, showed that six to nine weeks after a jab, the risk of catching flu creeps up by about 5 per cent; by 18 to 21 weeks, the risk is 27 per cent higher.

This drop in immunity is why the Joint Committee on Vaccination and Immunisation, the body which advises UK government on vaccine policy, recommended this year’s flu jab programme kicked off in early October – a month later than usual – to ensure more people are still well-protected during the expected peak flu infection times of late December and January.

‘The timing of the flu vaccine is crucial because it does decline in effectiveness,’ says Professor Easton.

‘You get an immediate strong response and then it tails off – although never quite to zero and you’ll still have some immunity left throughout winter.’

So should you consider delaying your jab?

The data suggest that for maximum protection in peak December/January infection times, then mid to late November might be the best time. But you still get some protection if you have it before or after then.

WHAT ABOUT HAVING NOT JUST ONE JAB BUT TWO?

On the basis that the effect of the jab wanes with time, shouldn’t we all be offered a booster around December or January?

A 2022 study in the journal Vaccines, by the University of Pittsburgh in the US, showed hospitalisations among the elderly could be cut by up to 19 per cent if they had two jabs – spread a few months apart – rather than one.

The double-jab strategy was particularly effective in years when flu infection rates peaked late in the season – February or even March – the study showed.

But the idea has failed to take off in the UK or other countries because booster vaccines tend to get an even weaker response from the immune system than the first one and, experts say, it’s highly likely that uptake would be even lower.

‘It would be very difficult to get people back for another jab,’ says Professor Easton.

‘Uptake with just one vaccine is already very disappointing and it would take up a lot of NHS time and resources to provide a second one.’