in Science

Why I got my flu shot

I’m 32 years old, relatively healthy and have only ever had the flu once. I’m not in any high-risk groups. I’ve never had a flu shot that I can remember.

So, why would someone like me bother with it?

Health bodies in the UK, Europe and the US are expecting a severe flu season this year. In Australia there were over twice as many confirmed cases of flu in the 2017 season and a young mum, a 30-year-old dad and an eight-year old girl died. Those are rare cases, but illustrate the fact that flu can be deadly, even for people in the prime of their lives.

Because of this there has been an increased campaign urging people to get flu shots this year. I’m a strong advocate for vaccines in general, but the flu vaccine is a more nuanced topic than, say, childhood vaccines.

A tricky beast to tame

Flu vaccines are either trivalent or quadrivalent, meaning they aim to protect against the most common three or four strains of the flu virus as recommended by the WHO each year.

The vaccine contains inactivated (essentially dead) viruses which can’t give you the flu, but do stimulate an immune response. That can cause some side effects, most commonly aches or mild fever, and a sore area around the injection site. As I write this, my arm is indeed a bit sore but so far that’s the only side effect I’ve experienced. Very rarely more severe reactions can occur but these are expected within minutes after the shot so if you’re worried you can just sit for a while.

One of the problems with the flu vaccine is that its effectiveness can be compromised by the rapidly-changing nature of the virus. It takes six months to manufacture the vaccine so if a new strain suddenly becomes widespread, the shot wouldn’t fully protect against that, although there is some cross-protection for other strains and there is evidence to show that having the shot will make any flu you do catch less severe. Also, it takes up to two weeks for immunity to fully develop so it is still possible to catch the flu in that time. There will likely be geographic differences in what strains are circulating, so a vaccine that performs well in one country may not perform so well in another. Finally, it is possible to contract the flu but have no outward symptoms.

These factors make developing a flu vaccine and knowing how effective it is difficult. However, the reported effectiveness for last year’s flu vaccine here in the UK was 40.6% in adults aged 18–64. That may not sound great compared to other vaccines but given the difficulties involved it’s not bad and certainly better than nothing.

In under-18s the vaccine was actually more effective at 65.8% but in people 65 and over the results were not so good, with only a 6.3% effectiveness rate.

Now we come to the real reason why I got my flu shot — herd immunity.

It’s not about me

As with all vaccines, the benefits are wider than just the individual getting the shot. There will always be some people who can’t get vaccines, or for whom the immunity simply doesn’t take hold.

I may not be in a high-risk group myself, but I have friends and loved ones who are, so I got my shot to help protect them too. If I can reduce my risk of contracting the flu, I’m also reducing my risk of passing it on to others.

My dad is in the over-65 bracket and has a chronic health condition so he’s in two high-risk groups. He’ll go and get his flu shot this year like every year, but I know that the vaccine is likely to be less effective for his age group. That means it’s more important for me to get my shot in order to help protect him. He lives in the countryside whereas I live in the big city, which means I’ll probably be exposed to more carriers and more strains of flu. When I go to visit I want to do everything I can to avoid unwittingly introducing him to a strain he wouldn’t otherwise have encountered.

Likewise my friends who are new or expectant parents. Newborns and pregnant women are both high-risk groups, but I also know that recent parents really don’t need a dose of the flu on top of everything else on their plate!

Finally I’m thinking about people with compromised immune systems, and the people who come into contact with them on a regular basis. I don’t want to go into much detail on this for obvious reasons but most of us will know people who fall into this bracket at some point in our lives, sadly.

The greater good

For people like me, the negatives of the shot are minimal — some time out of my day, a few bucks out of my pocket, and some mild side effects. The positives, however, are potentially far greater both for myself and for the people around me. I think any chance of avoiding passing on the flu is worth these minor downsides. The flu vaccine isn’t perfect, but I think that just makes it more important to have the highest possible coverage.

What I do as an individual is one thing, but the more of us who get the flu shot the better. Every person who gains immunity is one less pathway for the virus to reach an at-risk person.

That’s why I got my flu shot, and I hope you’ll join me.